The Truth About Leaky Gut Syndrome: What is It and How Do You Heal?

leaky gut syndrome

Is leaky gut syndrome real? Here’s what you need to know about this condition, how it affects your body, and how to heal for good.

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What is Leaky Gut Syndrome?

Think about your digestive system for a second — from mouth to anus, it’s really just one long tube that dictates what can be absorbed into your bloodstream and what passes through the body. It knows that things like nutrients and water are important to absorb into the bloodstream, while toxic particles and undigested foods should make their way to the large intestine to be passed out of the body in the form of stool.

The gut barrier is one single cell layer thick and is connected by “tight junctions” that hold the cells together. This single layer of cells and the tight junctions between them are the only things preventing harmful particles from entering your bloodstream.

When the gut is functioning normally, these tight junctions hold the cells that make up your gut barrier together and only allow small particles (like nutrients) into the bloodstream.

Leaky gut syndrome, or increased “intestinal permeability,” is when the tight junctions holding the cells of your gut barrier together don’t function properly and the cells drift apart, allowing larger molecules like bacteria, undigested food particles, and waste products into the bloodstream.

Think of the gut barrier like a strainer. It only lets things of a certain size pass through, while anything too big will be kept out. Now imagine the holes in your strainer getting bigger, thus allowing larger particles through. That’s exactly what’s happening to your gut when you have leaky gut syndrome.

When you have leaky gut, your body is bombarded with unrecognized particles like lipopolysaccharides (LPS) that are present on the outer membrane of bad bacteria as they make their way through the bloodstream. Your immune system goes into high alert to try to protect you from these toxic particles, and as a result, you develop a high amount of inflammation.

This high level of LPS in the blood is associated with many conditions, as you can see below.

Rodriguez-Castaño GP, Caro-Quintero A, Reyes A, Lizcano F. Advances in Gut Microbiome Research, Opening New Strategies to Cope with a Western Lifestyle. Frontiers in Genetics. 2016;7:224. doi:10.3389/fgene.2016.00224.

I’ve written more about microbial imbalance and the resulting inflammation, and how that contributes to disease (specifically metabolic disease) in this article.

Is Leaky Gut Real?

There’s a lot of controversy over the term “leaky gut,” particularly the use of the term “leaky gut syndrome,” which seems to indicate that this condition is an official medical diagnosis.

Leaky gut syndrome is not a medical diagnosis, however, leaky gut is indeed a very real phenomenon that is seen throughout the scientific literature. Leaky gut is simply the more colloquial term for increased “intestinal permeability” or “intestinal hyperpermeability,” which are the terms you’ll see most often in the scientific research. (Though the term “leaky gut” is even catching on in research, and you’ll see that now too!)

In fact, at the time of this posting, there are over 90,000 Google Scholar results for the term “intestinal permeability”, and as you’ll see throughout the rest of this article, intestinal permeability is associated with a vast array of diseases and conditions.

What Causes Leaky Gut?

While there’s a lot we’re still learning about leaky gut, there are a few things we know of already that can cause this syndrome.

Gut Microbiome Imbalance (Dysbiosis)

Having an overload of bad gut bacteria (or dysbiosis) is one of the top causes of leaky gut syndrome. That’s because these bad bacteria have a toxic molecule on their outer membrane called lipopolysaccharide (LPS) that is highly inflammatory.

LPS causes gut inflammation, which causes the cells of the gut barrier to pull further apart, leading to leaky gut syndrome.

When you have both leaky gut and dysbiosis, the LPS that causes leaky gut then gets into the bloodstream, taking inflammation to the rest of your body and putting your immune system on high alert.

You can read more about dysbiosis and how it contributes to leaky gut and other diseases here.


Stress is also a huge factor when it comes to leaky gut syndrome. Researchers have known for a long time that severe physical stress such as trauma or surgery causes the intestinal lining to become “leaky”, but more recent research has started to look at the effect of chronic psychological stress on the gut barrier.

To approximate chronic psychological stress in humans, rats are repeatedly subjected to water aversion stress where they are placed on a platform surrounded by water. Researchers have found that this is a mild stressor to the rats, similar to the type of chronic mild stressors we face today. So what happens to these rats? They develop intestinal permeability that takes several days of no stress to heal.

This mild, chronic stress directly causes the cells of the gut barrier to drift apart, which, as discussed earlier, allows toxic particles to filter through into the bloodstream.

In addition to this, stress also imbalances gut bacteria, which also leads to the development of leaky gut syndrome in and of itself.

Certain Pharmaceutical Drugs/Alcohol

Certain drugs like NSAIDs (e.g. aspirin and ibuprofen, among others) are known to cause leaky gut. Alcohol also has the same effect.

However, it should be noted that it is chronic, excessive use of these items that leads to major intestinal permeability, so don’t worry if you like to enjoy a glass of wine or need to take an aspirin every once in a while!

That said, if you’re actively trying to heal from leaky gut (and not just trying to prevent it), it’s a good idea to limit your alcohol intake and avoid using NSAIDs as much as possible.


Diet plays a very important role in digestive health. An unhealthy diet, high in sugars and unhealthy fats while low in fiber, can lead to the development of leaky gut syndrome. This is because an unhealthy diet encourages the growth of bad gut bacteria. Unfortunately, this is common on a Standard American Diet (SAD).

In addition to eating unhealthily, consuming foods that you are allergic or sensitive to can also lead to irritation and inflammation in the gut and intestinal permeability.

Leaky Gut Symptoms

According to the scientific literature, there are a number of conditions that are associated with increased intestinal permeability, both within the digestive system as well as outside of it.

These conditions include:

    • Ulcers
    • Diarrhea
    • Irritable bowel syndrome (IBS)
    • Inflammatory bowel diseases (IBD — ulcerative colitis and Crohn’s disease)
    • Celiac disease
    • Cancer, esophageal and bowel
    • Allergies
    • Infections
    • Acute inflammation
    • Chronic inflammation
  • Obesity-associated metabolic disease

Now, this does not necessarily mean that leaky gut itself causes these conditions, just that intestinal permeability is commonly seen in these conditions.

However, there is research that indicates that leaky gut is present before the development of disease which makes researchers believe that it may be a “requirement” of sorts to develop various diseases.

However, it has given researchers a lot to think about as they explore leaky gut treatment possibilities to help prevent, treat, or reverse some of these conditions. I, for one, am very excited to see where the science leads us.

Testing for Leaky Gut

Leaky Gut Tests on the Market

There are two common tests for identifying leaky gut: differential sugar tests (like the lactulose mannitol test) and the zonulin test.

Differential sugar tests (DSTs) are considered the “gold standard” in leaky gut testing. For this test, you drink a solution containing specific sugars and then the levels of these sugars are measured a few hours later in your blood or urine. The idea here is that large oligosaccharides, like lactulose, do not pass through the gut barrier, while small monosaccharides, like mannitol, do. By testing for the sugars in the bloodstream or urine after consuming them, you’re able to see the degree of intestinal permeability that is present.

Testing for zonulin in the blood is, unfortunately, not a great way to determine if you have leaky gut. Zonulin levels do not seem to correlate with other markers of intestinal permeability (like the DSTs mention above), and zonulin levels are constantly changing, making one single measurement of this protein a fairly useless measurement of intestinal permeability.

Testing for zonulin antibodies, on the other hand, may prove a more useful measurement.

If you want to test for leaky gut, a differential sugar test or a zonulin antibody test is your best bet.

But that brings us to our next question… Is testing for leaky gut even worth it?

Is it Worth Testing for Leaky Gut?

I’m going to cut right to the chase here and say… No.

I’m not a big fan of testing for leaky gut because it never changes how we’re going to address it.

Truth is, there’s always something else causing leaky gut, like bad gut bacteria (dysbiosis), a poor diet, stress, food intolerances, etc.

So I’d much rather test for or evaluate those areas of my client’s lives than test for leaky gut.

Because, really, if I see someone who has digestive issues or an autoimmune disease or any of the conditions I mentioned above that are associated with leaky gut, I’m 99% sure that they have leaky gut anyway. I don’t necessarily need a test to tell me that because it’s not going to change how I approach the situation.

Instead of testing for the “symptom” (leaky gut), you want to test for the root cause (gut bacteria, stress, diet quality). Because when I know that a client has dysbiosis and their diet isn’t great and they have a stressful job, addressing all of those things is what is going to heal their leaky gut.

Save your money for gut bacteria testing instead of spending it on leaky gut tests!

Healing Leaky Gut

Now, just because testing for leaky gut is somewhat pointless doesn’t mean you shouldn’t treat leaky gut. As I hope you realize by now, leaky gut is indeed a real phenomenon that is important to address.

You may have heard that you can take supplements alone to heal leaky gut, but the crux of a leaky gut syndrome treatment plan tackles gut microbial imbalance, diet, and stress (with supplements to help along the way).

Leaky Gut Treatment Plan

The Leaky Gut Cure: Balancing Your Microbiome

The #1 cause of leaky gut is an imbalanced microbiome (dysbiosis). It is absolutely vital that you determine if you have bad gut bacteria and balance your microbiome if you want to cure leaky gut.

If you find you have imbalanced gut bacteria through SIBO testing or stool testing, you must get rid of that bad bacteria in order to heal leaky gut.

This is done by using herbal or pharmaceutical antimicrobials, dietary changes, stress reduction, and more. You can read more about how to get rid of bad bacteria here.

If you want to learn more about bacterial imbalance and how to fix it, I encourage you to take my free training by clicking the image below!

leaky gut syndrome

Leaky Gut Diet

As mentioned previously, a Standard American Diet full of unhealthy fats and sugars and low in fiber is a recipe for disaster when it comes to leaky gut.

Researchers are also worried about the impact of processed food additives, like emulsifiers and solvents, on our gut barrier, so avoiding processed foods is a good idea.

The best thing you can do from a dietary perspective to heal leaky gut is to eat an organic, nutrient-dense, whole foods diet that is high in fiber and prebiotics and low in unhealthy fats and sugars. You can read more about my dietary philosophy when it comes to supporting a healthy gut here.

The best foods to heal leaky gut include:

    • Non-starchy vegetables (broccoli, cabbage, leafy greens, etc)
    • Starchy vegetables (potatoes, sweet potatoes, yucca, taro, squash, etc)
    • Fruits (bananas, oranges, berries, apples, etc)
    • Meats (beef, pork, chicken, duck, etc)
    • Seafood (oysters, scallops, shrimp, sardines, etc)
    • Healthy fats (Olive oil, avocado oil, animal fats, etc)
    • Nuts (walnuts, macadamias, almonds, etc)
    • Legumes (if tolerated — lentils, beans, chickpeas, etc)
  • Dairy (if tolerated — yogurt, cheese, etc)

As much as possible, choose organic foods to avoid pesticides and additives. When trying to heal from leaky gut, it’s also wise to limit the amount of alcohol you consume.

Repair a Leaky Gut with Stress Management

Chronic stress induces intestinal permeability, so it’s imperative on any leaky gut treatment plan to incorporate stress management techniques.

Deep breathing, meditation, chi gong, yoga and more are options, but really, any stress management technique that you enjoy and are likely to do on a regular basis is best!

I find that my clients benefit more from practicing these techniques for shorter periods of time more often (for example, 5-7x/week) than doing a long session, say, once a week.

Best Supplements for Leaky Gut

There is a lot of really promising research looking at the best supplements for leaky gut, but it’s important to remember that supplements do not negate the need to address things like dysbiosis, diet, and stress.

You can take a million supplements for leaky gut, but if you’re not addressing those main causes of intestinal permeability, supplements really won’t get you very far. As much as I would love to tell you otherwise, there is no magic pill.

Supplements are used to “supplement” an existing treatment plan; they can help speed up the process of healing or make it easier, but they themselves won’t cause any lasting change on their own.

Antimicrobials Kill off Bad Gut Bacteria

It is clear that imbalanced gut bacteria, or dysbiosis, plays an enormous role in the development of leaky gut.

Because of that, it’s absolutely necessary to kill off bad bacteria and encourage healthy growth of beneficial microbes.

Most often, getting rid of bad bacteria is going to require being on antimicrobials of some kind (whether they are herbal or pharmaceutical).

As a dietitian, I’m a big fan of herbal antimicrobials. Here are some of my favorites to use:

    • Oregano oil (found in Biotics Research ADP — I like this one in particular because it’s a time-released oregano supplement)

Probiotics for Leaky Gut

Probiotics, in general, have proven to be very helpful in restoring and maintaining proper gut barrier integrity.

However, we need to remember that probiotic effects are strain-specific, so it’s important to pay attention to the exact strains that have been shown to be helpful (so that if you buy a probiotic to take, you know you’re getting a strain that actually has been proven to improve leaky gut!).

Here are the best probiotics for leaky gut:

Prebiotics for SCFA Production

Prebiotics are a powerhouse when it comes to healing leaky gut. It has been shown that supplementing with prebiotics reduces LPS concentrations in the blood. Remember that LPS is the toxic molecule on the outer membranes of bad gut bacteria. When you have a permeable gut, more of this toxic particle gets into your bloodstream and wreaks havoc from there. So when researchers are trying to determine whether a substance reduces leaky gut or not, they can look at the amount of LPS that ends up in your blood.

Now, prebiotics are different from probiotics. You can think of prebiotics as the food or fuel for probiotics; in essence, they feed your good bacteria so that you have plenty of the good guys around.

In addition to this, prebiotics also increase your production of short-chain fatty acids (SCFAs) which help to heal and seal the gut barrier as well as reduce inflammation (since less inflammatory LPS particles are getting through to the bloodstream).

My favorite prebiotics include:

A quick note about the Sunfiber supplement is that, unlike other prebiotics like GOS or FOS, Sunfiber is low-FODMAP and thus does not tend to increase digestive symptoms like bloating or gas like higher-FODMAP choices do. It also mixes really easily with water or other liquids, so it’s super easy to take.

Quercetin Seals a Leaky Gut

Quercetin is a really useful tool for helping to heal leaky gut. In fact, I’ve written a whole article on the topic!

We’ve already discussed the fact that stress increases intestinal permeability. Part of how this happens is that stress “destabilizes” or “degranulates” mast cells.

You may have heard of mast cells before as the cells responsible for allergy symptoms, like congestion, runny nose, etc. This is because when mast cells “degranulate” or become “unstabilized,” they release histamine, the chemical that causes allergy symptoms.

But you have mast cells all throughout your gut too, and when they “degranulate” or become “unstabilized” there, they cause leaky gut.

So how does quercetin fit into the picture?

Quercetin is one of the most abundant flavonoids present in our food supply, found in high amounts in onions, kale, and apples. It is well-known for many things, including its anti-allergy properties, anti-cancer effects, and as an antioxidant. But did you know that it can heal leaky gut too?

Since intestinal permeability is caused (at least in part) by unstabilized mast cells in the gut, it makes sense that quercetin would have this effect. This is because quercetin stabilizes mast cells and prevents the release of histamine and other chemicals from these cells. When researchers breed rats to have no mast cells in the gut (thus they are unable to have unstabilized mast cells that release histamine), they no longer develop intestinal permeability.

Quercetin has also been shown to enhance gut barrier function by having a “sealing” effect due to its role in the assembly and expression of tight junction proteins. Tight junctions regulate our intestinal permeability by connecting intestinal cells, thus only allowing the nutrients that we need in and keeping everything else out.

As you can see, adding quercetin to your leaky gut supplement protocol can really do a lot to help keep that gut barrier sealed up!

There are plenty of quercetin supplements on the market, but one of my favorites is the Source Naturals Activated Quercetin supplement.

Collagen Repairs a Leaky Gut

Collagen is the most abundant protein in our body, and is found in high amounts in the gut. It is also a potent source of the amino acid glycine.

As humans, we are meant to eat a mix of both glycine and methionine (among other amino acids), but in the modern world where we don’t tend to eat nose-to-tail, that can be difficult. You see, glycine is abundant in animal products that we don’t usually consume, like tendons, ligaments, and bone while methionine is present in high amounts in muscle meat (think steak, chicken breast, etc). This altered ratio of methionine:glycine intake is thought to be related to our increase in chronic disease rates. I highly recommend watching Denise Minger’s Ancestral Health Symposium talk on this topic.

Because of its role in the gut, collagen peptides have been found to heal leaky gut by improving tight junction function.

There are many collagen peptide supplements on the market right now, but I’m a big fan of the Vital Proteins line.

L-Glutamine Fuels Gut Cells

Glutamine is an amino acid and is a major fuel source for intestinal cells.

It has been studied and used for years in relation to its ability to reduce intestinal permeability in critically ill patients.

In addition to this, glutamine supplementation can also improve gut bacteria balance.

This gives you a great combination of benefits: glutamine balances your microbiome and heals leaky gut.

While capsules may seem like the easiest to take, you’re actually better off getting a powder for supplementation. This is because you’re generally going to want fairly high doses of glutamine to get the benefits for leaky gut.

In healthy adults, the observed safe level of l-glutamine is 14g/day. Considering that most capsules contain a maximum of about 1000mg, you’d have to take 14 of them every day!

Therefore, an L-glutamine powder is a much better choice for leaky gut.

Vitamin D Keeps Your Gut Healthy

Vitamin D is one of those vitamins that you sit and wonder… “What can’t Vitamin D help with?!”

From bone health to the immune system, Vitamin D plays a role in almost every facet of our being — and that includes preventing and healing leaky gut.

You see, Vitamin D deficiency makes you more likely to have leaky gut. The good news, however, is that supplementing with Vitamin D can keep your gut barrier in good condition.

You can get Vitamin D from sun exposure, food, and supplementation. Getting proper sun exposure is the best way to get your Vitamin D, of course! There are very few foods that contain a lot of Vitamin D, so it’s somewhat difficult to get your D from your diet.

If you’re not getting enough sun exposure to get adequate Vitamin D, your next best bet is to supplement.

I recommend taking a Vitamin D3 supplement. Depending on your current blood levels, taking anywhere from 2000 – 5000 IU per day is a good idea.

And because fat-soluble vitamins work synergistically, I recommend taking a combination supplement that also includes Vitamin K2, like Thorne’s Vitamin D/K2 Liquid.

Zinc Improves Gut Barrier Integrity

Zinc is an important mineral that is used in a variety of processes within the body to keep us healthy.

When you’re deficient in zinc, your body’s ability to heal wounds may become impaired, your immune system may not function as well, and you might develop anemia, hypogonadism, or mental illness.

In addition to this, your gut barrier may become impaired. Zinc supplementation has been shown to improve gut barrier integrity in those with Crohn’s disease. It does this by strengthening the tight junctions that hold the cells of the gut barrier together.

I like to incorporate zinc into any leaky gut supplement protocol for these reasons. Zinc carnosine is my favorite form of zinc for leaky gut as it’s been shown to heal leaky gut and help repair gut cells.

I like Integrative Therapeutics’ Zinc Carnosine supplement.

How Long Does It Take to Heal Leaky Gut?

As I mentioned before, treating leaky gut requires a multi-pronged approach. You need to get rid of bad gut bacteria, manage your stress, and eat well. Supplements can help you do these things, but they’re not the end-all-be-all of leaky gut treatment.

When people ask this question, what they really mean is “How long will it take before I feel better?” That can really depend.

If you have an autoimmune disease and believe leaky gut is playing a role in that, the truth is you may never fully recover from autoimmunity. That said, healing your gut can improve your symptoms immensely. I’ve seen symptom improvement in as little as a month, while others can take 6 or more months to really see significant benefits.

If you have digestive issues that you think are caused by leaky gut, I’ve found that healing your gut goes a long way toward recovery. Just as with autoimmune diseases, I’ve seen significant improvement in as little as a month when really addressing all aspects of a leaky gut treatment plan.

When it comes down to it, how long it will take you to heal leaky gut totally depends. It depends on how long you’ve been dealing with gut issues, how much you’re able to commit to the changes that need to be made to heal your gut, and then it’s just about how your body (we’re all different, right?) responds.

The short answer: on average it can take anywhere from 1-6 months to actually feel better when you’re trying to heal from leaky gut (though it may take longer for your gut barrier to completely repair).

Heal Leaky Gut For Good

While I hope this article has given you a lot to start thinking about, if you want to learn exactly how to address digestive issues, I’d like to invite you to join my free training.

You’ll learn:

    • How to fix digestive issues even if you feel like you’ve tried everything before
    • How to determine the cause of digestive issues and heal them for good
  • How to overcome food sensitivities

I’ll go into more detail on the gut bacteria imbalances that cause leaky gut (remember you have to get rid of those bad guys if you ever want to heal leaky gut!).

Want to join me? Click the image below to sign up!

leaky gut syndrome

How Do You Know If You Have Bad Gut Bacteria?

bad gut bacteria

You’ve probably heard the words “gut microbiome”, “gut bacteria”, or “gut flora” quite a bit these days.

Maybe you’ve even read a few articles on why you should pay attention to your gut bacteria and how important they are for your overall health.

You know that “bad bacteria” aren’t great for your health…But now you’re wondering – how do I know if I have bad bacteria? Hint: you might have bad bacteria even if you don’t have digestive issues.

Let me walk you through it!

What is the Microbiome

First, it probably makes sense to go over exactly what the gut microbiome is because this is what becomes unbalanced, leading to chronic health conditions.

The gut microbiome is often referred to as the “forgotten organ” by scientists because it plays such a vital role in your health. Just like your heart and your lungs are required for you to thrive, so is your gut microbiome.

Your gut microbiome is comprised of trillions of bacteria, yeasts, and viruses. We generally classify all of these microorganisms into three different categories:

Normal Flora

Normal flora are exactly what they sound like — the normal bacteria that you expect and want to find in your microbiome. These are our good guys; the flora that do all the good things we associate with a healthy microbiome like make vitamins, support the immune system, and more.

That said, you can have perfectly normal flora growing in the wrong place, which can also cause symptoms. This is the case for SIBO (small intestinal bacterial overgrowth), which can cause diarrhea, constipation, and excessive bloat

Potential Pathogens

Potential pathogens are gut flora that have the potential to be pathogenic (harmful, causing symptoms). While some of these can be found in small amounts and not be problematic, if they start to grow out of control, they can become pathogenic and cause you symptoms. So it’s important to make sure that these flora are found in small amounts (or the right amount) and are not overgrowing with the potential to cause symptoms.


Pathogens or pathogenic bacteria are the bad gut bugs — these are ones that, if found, are very like to make you symptomatic. Depending on the pathogen, that could mean symptoms from anything like bloating, excessive gas, flatulence, abdominal pain, diarrhea, constipation, reflux, and more. Basically, we don’t want to see these on your testing!

When your gut microbiome is well-balanced, it helps you digest food, make nutrients, influences the immune system and the metabolic system, and more. Clearly, we want these bacteria balanced!

When gut bacteria become imbalanced, they can cause a host of symptoms including diarrhea excessive gas, bloating, constipation, diarrhea, abdominal pain, reflux, and more. Imbalanced gut bacteria can also cause symptoms outside of the digestive system, too, which I’ll talk more about in a few moments.

What is Unbalanced Gut Bacteria?

When you hear the terms “bad gut bacteria” or “imbalanced gut flora” or “unhealthy microbiome”, this can refer to a number of different conditions. The most common include small intestine bacterial overgrowth (SIBO), microbial dysbiosis (an imbalance of gut flora in the large intestine), pathogens, or parasites.

Let’s do a quick rundown of each of these conditions:


The small intestine should be relatively sterile when compared to the large intestine, which houses the majority of our bacteria in the microbiome. When bacteria translocate to the small intestine for any reason and overgrow, you now have an overgrowth of bacteria in the small intestine; hence, “small intestine bacterial overgrowth” or SIBO. This is a very common condition and one I see a lot in my practice.


The term “dysbiosis” simply means an imbalance of bacteria (which could be anywhere in or on the body), but it’s commonly used to describe an imbalance of gut bacteria in the large intestine, specifically. I like to break down dysbiosis into two categories (well, 3 really, but we’ll talk about the 3rd option – parasites and pathogens – next).

Insufficiency Dysbiosis

This is when you don’t have enough beneficial bacteria like Lactobacillus or Bifidobacteria hanging out in the large intestine. These should be present in high amounts, but it’s very common to see folks with very little or no growth of these beneficial microbes.

General Imbalance 

This is when you have too few beneficial bacteria and overgrowths of one or more commensal bacterial strains. Commensal bacteria are bacteria that are normal to find in small amounts and typically don’t cause any harm to you. However, when they start growing in high amounts, you might start developing symptoms.

Parasites or Pathogens

Parasites or pathogens are specific strains of bacteria that, when present, can cause harm or disease. With potential pathogens, you can usually have a small amount that won’t necessarily be problematic, but they may start to cause symptoms as their numbers grow higher.

Symptoms of Imbalanced Gut Flora

Okay, so now that you know what different types of imbalanced bacteria you might have, what are some symptoms you might experience if you were to have any of these types of bacterial issues?

The symptoms that can accompany the different types of imbalance are quite diverse. However, there are a few general symptoms you can look for with the different imbalances that might clue you in to whether you’re more likely to have one or the other.

Remember, though, that you can have these imbalances and have absolutely zero digestive problems; some people just don’t exhibit digestive symptoms even if they have a severe imbalance in their microbiome. But just because you don’t feel digestive symptoms doesn’t mean that an imbalanced microbiome isn’t harming you; it’s still having a negative impact on all your other body systems. Very important to take care of it even if you don’t notice any digestive symptoms.

heal your gut

Symptoms of Bad Gut Bacteria

SIBO Symptoms

Wondering what causes bloating? The most common symptom of SIBO is excessive bloating or stomach distension. You get bloated when you have SIBO because when the overgrowing bacteria in the small intestine are exposed to carbohydrates or fiber from your diet, they ferment them and produce gas as a result. As you can imagine, this can not only cause bloating but it can also lead to symptoms like flatulence or excessive gas. The increased pressure in the GI tract can also lead to reflux. (1) SIBO is also associated with diverticulitis. (2)

When you test for SIBO, there are two different types that will show up: methane-positive or hydrogen-positive.

Methane-positive SIBO commonly causes you to become constipated, while diarrhea is associated with hydrogen-positive SIBO. (3)

You can also exhibit no digestive symptoms at all when it comes to SIBO. This is because having an infection in the gut can cause disease outside the digestive system. We’ll talk more about these different conditions in the next section, but I just want you to know that you can have absolutely zero digestive symptoms and still have bacterial imbalance in the gut.

To recap, SIBO symptoms include:

  • Bloating/Bloated Stomach/Distended Stomach
  • Excessive Gas
  • Constipation
  • Diarrhea
  • Abdominal pain
  • Flatulence
  • Belching

Large Intestine Dysbiosis Symptoms

The symptoms for gut dysbiosis in the large intestine vary a lot, and I find that a lot of the time dysbiosis is associated with disease states that occur outside of the digestive system. However, there are certainly people who develop gastrointestinal symptoms when they have dysbiosis.

With insufficiency dysbiosis, the most common symptom I see is constipation. Symptoms of just a general imbalance of bacteria in the large intestine vary widely. They can include constipation, diarrhea, bloating, or general pain or sensitivity in the abdomen.

Pathogens and Parasites

These have more specific effects depending on which parasite or pathogen you have. For example, if you have H.Pylori you might have reflux or ulcers, while klebsiella pneumoniae is associated with ankylosing spondylitis. Other pathogens and parasites can simply cause ongoing digestive symptoms like diarrhea or bloating.

Conditions Associated With Imbalanced Gut Bacteria

As I mentioned previously, you do not need to have digestive symptoms to have imbalanced gut flora. Imbalanced gut flora is probably more common than most people think because of this – after all, it’s strange to think that the bacteria in your gut have anything to do with the rest of your body.

Conditions/Diseases Associated with SIBO

Conditions/Diseases Associated with Dysbiosis

Specific Pathogens/Parasites and Their Associated Symptoms/Diseases

Gut Microbiome Testing

Testing your gut for imbalanced bacteria is hugely important. You may not even know that you might have an imbalanced microbiome!

I wish it was cheaper to test (and hopefully we’ll see prices go down on these tests in the coming years) because I think everyone should do it. Since a healthy, balanced microbiome is vital to your overall health, you owe it to yourself to make sure your microbiome looks good.

Because there are so many different symptoms of bacterial imbalance, I find it’s very useful to test so you know what bacteria you actually have and what might be missing.

Because not all bacterial imbalances show themselves in the way of digestive symptoms, you may not think you need to worry about your gut bacteria, but hopefully, you’ve learned a thing or two in this article that makes you think twice about that assumption!

To test your gut bacteria, I recommend doing two types of tests: a SIBO test and a stool test.

SIBO Testing

I’m currently using the SIBO test from Biohealth in my practice, which I like a lot. If your doctor is familiar with SIBO or is open to learning more about it, you may be able to get them to order a SIBO test for you that might be covered by your insurance plan.

However, many doctors won’t test for it, unfortunately (though this is becoming less and less common as the topics of the microbiome and SIBO become more popular). If your doctor will order a test for you, I recommend asking to make sure it’s at least a 2-hour test that looks at both hydrogen and methane gas. Remember I said that which gas you produce dictates how you deal with it, so it’s important to get that information!

You can also order SIBO testing online.

Stool Testing:

As for stool tests, my favorite is the GI-MAP test from Diagnostic Solutions Laboratory. It’s a very accurate test, needing only one stool sample for parasitology. Other stool tests companies recommend getting the higher sample rates (for example, Doctor’s Data offers a 1 sample, 2 sample, or 3 sample kit) but GI-MAP can get it all in just 1 sample.

I still think other options for stool testing are good, like Doctor’s Data, Biohealth, and Genova, but personally, I’m liking the GI-MAP these days. These types of stool tests tend to be a bit harder to get from your doctor unless you’re going to a functional medicine doctor. I’ve seen some tests be covered by insurance (at least partly) before, but a lot of times it’s difficult to get these tests from someone who can help get it covered by insurance, sadly!

If you want to test your gut bacteria, I recommend asking your doctor about your options first. If you can’t get it covered or they can’t or won’t order them, you’ll need to find another healthcare practitioner to order through, or you can order it online.

In my online program, Build Your Biome, you get these tests (at a discount) and I’ll tell you what everything means and how to deal with it appropriately.

How to Get Rid of Bad Bacteria in The Gut

If you’ve done some of this testing and find out that you have SIBO, dysbiosis, parasites, pathogens, candida, H. Pylori or something else, you’ll want to make sure to clear out any bad or overgrowing bacteria for optimal digestive and overall health.

Depending on what your microbiome is dealing with, you have a few options.

Herbal Antimicrobials

Many herbs have antimicrobial properties, meaning that they kill off microbes. When you have overgrowing microbes in your gut, this is exactly what we want! Some common antimicrobial herbs and nutrients include: oregano, berberine, garlic (allicin), artemisinin, black walnut, caprylic acid, and more.

I highly recommend working with a professional if you’re going to go this route as you want to make sure that the antimicrobials you are choosing are appropriate for the bacteria found in your testing.

Pharmaceutical Antibiotics

While antibiotics can have a lot of unfortunate side-effects, they have a time and place. If you have a microbial imbalance that warrants antibiotics, it’s smart to take them as prescribed.

It is always wise to bring any gut testing that you’ve had done to your doctor so that they can advise you on the proper next steps.

Elemental Diet

An elemental diet is a meal replacement diet that consists of highly broken down nutrients. They’re so broken down, in fact, that they don’t even make it to your small or large intestine where they can feed bacteria.

Because this type of diet (really, it’s a supplement more than anything else — diet doesn’t fix microbial imbalance) doesn’t feed bacteria, it can be used to starve bacteria and kill them off. You need to use it long enough for it to have this effect, though (generally at least 14 days).

While it’s not the most pleasant thing to be consistent with, it works very well.

If you’re interested to read more about an elemental diet, you can read my article (originally published on here.

Lifestyle Changes

To be clear, lifestyle changes alone do not get rid of microbial imbalance. However, they make your antimicrobial/antibiotic/elemental diet so much more effective at killing off bad gut bacteria and keeping bad bacteria away once you finish up your course.

The lifestyle changes I incorporate into my Build Your Biome program include stress reduction, stress management techniques, gut-directed hypnosis, dietary changes (making sure you’re eating enough and choosing healthy options), journaling, sleep enhancement, proper exercise (both the amount of exercise and recovery that you do), and more.

Even though these things alone can’t get rid of bacteria, they are the foundation upon which your digestive health stands. If these factors aren’t taken care of, you make your body’s job so much harder and it’s going to take you longer to get rid of bad gut bacteria and keep it away for good.

If you want to know more about how to get rid of the microbial imbalance that causes digestive problems (and more), check out my free training on the topic by clicking the image below.

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Wrapping it All Up

Gut health is so crucial to overall health, as I hope you’ve learned by reading this article! Imbalanced gut bacteria is associated with many health conditions and diseases, and clearing bad bacteria can make a world of difference if you’re suffering.

Testing your gut microbiome for bad bacteria is the best way to determine if you have any nasty gut bugs that need dealing with. I recommend two tests: the SIBO test and the Stool Test (GI-MAP being my favorite).

Need More Help?

Click the image below to get my FREE training on healing digestive problems the right way — for good.

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Can the Microbiome Affect Crohn’s Disease and Ulcerative Colitis (IBD)?

ibd ulcerative colitis crohns

Inflammatory Bowel Disease (IBD) refers to a group of diseases characterized by changes in the intestinal immune system and chronic inflammation of the intestinal walls.

The most common of these conditions are Crohn’s disease and ulcerative colitis. (1, 2, 3, 4)

Crohn’s Disease

Crohn’s disease (CD) is an inflammatory bowel disease that can affect any part of the digestive tract, from mouth to anus. (2, 5)  It causes patches of inflammation that extend deep into the intestinal wall, sometimes going all the way through. These inflamed patches are typically separated by areas of healthy tissue.  (2, 5)

The inflamed patches of intestine are very painful and the defining symptom of Crohn’s disease is abdominal pain. Poor digestion and absorption of food by the inflamed gut walls also leads to diarrhea (which can be bloody or mucus-filled), weight loss, and nutritional deficiencies (particularly anemia and vitamin B12 deficiencies). (3, 5)

Though the diagnosis of Crohn’s disease mostly relies on changes in the digestive tract, the overactivation of the immune system in CD is not restricted to the gut. Abnormal immune function in the disease leads to a variety of non-digestive symptoms, as well, including:  (3, 5)

  • fever
  • arthritis (in the joints or spine)
  • canker sores
  • inflammation of the eyes and
  • inflammation of fat cells below the skin (erythema nodosum)

Ulcerative Colitis

Though similar to Crohn’s in many ways, ulcerative colitis (UC) has some distinct features.

In UC, the immune system only attacks the surface of the colon and/or rectum, not deep into the intestinal wall.  The inflammation in UC is also continuous, rather than patchy. It never skips over patches healthy tissue. (2, 5)

These differences in nature of the intestinal inflammation in UC lead to slightly different symptoms.

Rather than abdominal pain, the defining symptom of UC is frequent, urgent and severe diarrhea that is nearly always bloody.

UC can cause abdominal pain and unwanted weight loss, but, since the inflammation in UC is more limited and doesn’t involve small intestine (where nutrients are absorbed), these symptoms are less common in CD. (2, 5)

Though the intestinal inflammation in UC is less widespread than in CD, it would be a mistake to think the immune dysfunction itself is somehow “limited”. It is still significant and has full-body effects. Similar to the body-wide symptoms of Crohn’s, UC can cause: (2, 5)

  • fever
  • osteoporosis
  • mouth ulcers
  • leg ulcers
  • arthritis
  • inflammation of the bile ducts
  • inflammation of the eyes
  • formation of blood clots in the legs or lungs

What causes IBD?

The exact cause of IBD has baffled researchers for decades. (2, 6)

Studies clearly indicate that there are genetic factors at play. Population studies show different rates of IBD amongst different ethnicities and a strong clustering of IBD within families. (3, 4, 7) Detailed genetic studies have even been able to find over 160 unique gene mutations directly linked to an increased risk of IBD. (7)

But data also clearly shows that IBD isn’t an actual genetic disorder, either.

None of the 160 risk genes identified are common to everyone who gets IBD. (7)

There is no decisive inheritance pattern for IBD, like one sees with true genetic disorders such as hemophilia or cystic fibrosis. (8)

IBD can’t even be the result of a combination of high-risk genes since identical twins (who have identical DNA) don’t always both get IBD if one does. (9)

To summarize, genes play a role in IBD development, but don’t seem to cause IBD.

How does that work?

The leading theory at the moment is best explained by the “loaded gun analogy”. (10)

The Loaded Gun Analogy

As the name suggests, the “loaded gun analogy” imagines the development of IBD to be similar to firing a bullet from a gun.

In order to fire a bullet from a gun you need to do two things: First, you have to load a bullet into the chamber. Then, you have to pull the trigger.

If you leave out either of these steps, you can’t actually fire a bullet!

If you load the bullet but don’t pull the trigger, the bullet just sits harmlessly in the gun. And if you pull the trigger, but forgot to load the bullet, nothing happens.

Similarly, researchers now think that developing IBD requires two steps.

The first step (“loading the bullet) comes from your genetic risk. Inheriting IBD-promoting genes acts like loading a bullet into the chamber of the gun.

The second step ( “pulling the trigger”) comes from something completely non-genetic: your environment. The right environment acts like a finger on the trigger of the gun, actually firing the bullet.

If you leave out either of these steps, you don’t actually get IBD. If you have the genes for IBD, but are never exposed to the right environment, your genes sit harmlessly in your cells. If you live in the perfect environment to develop IBD, but have no IBD genes, nothing happens.

Pulling the Trigger of IBD

Clearly, not every environment can “pull the trigger” for IBD, or everyone with a genetic risk would get the disease.

Only specific things in the environment, then, can be capable of “pulling the trigger”.

Have researchers been able to find any solid candidates for these environmental “trigger-pullers”?

Quite a few, actually.

Scientists compared the environments of people who developed IBD and people who didn’t (even though they had a genetic risk) and found lots of differences.

They found that those who got IBD tended to:

  • live in specific parts of the world (North America or Europe) (4)
  • live in cities (11)
  • include less fruits and vegetables in their diet (12, 13)
  • work white-collar jobs (13)
  • be stressed out for long periods of time (13)
  • have been bottle-fed as an infant (14)
  • have been exposed to cigarette smoke (for Crohn’s disease only) (13, 14)
  • have been exposed to excessive air pollution (14)
  • have low vitamin D levels (15)
  • have taken non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen (13)
  • not had their appendix removed (ulcerative colitis only) (13)
  • have had an intestinal infection (6, 13)
  • and have an unhealthy balance of gut bacteria (6, 14, 15, 16, 17, 18, 19, 20, 21, 22)

While scientists think all of these environmental factors are important, one has started to stand out over the last few years as one of the most important IBD-trigger: having unhealthy gut bacteria.

Unhealthy Gut Bacteria & IBD

There are 5 known ways that the microbes living in your gut can influence the development of IBD.  

Unhealthy Gut Bacteria Interact with the NOD2 Gene

The NOD2 gene is one of the most commonly mutated genes in IBD. It encodes a protein responsible for recognizing when bacteria are trying to sneak into the body. It sounds the alarm when this happens, telling the immune system to attack.

When it is mutated, NOD2 becomes very sensitive to unhealthy changes in the numbers and types of bacteria in the gut. Even small changes can cause NOD2 to tell the immune system to mount an enormous response.

Unfortunately, an enormous immune response damages the wall of the intestine. This damage is really small — smaller than the tiniest paper-cut you can imagine — but enough that bacteria from inside the gut can end up getting into the wall of the intestine itself.

Once in the intestinal wall, guess what these bacteria do? They are recognized by NOD2 because they are not supposed to be there. Of course, NOD2 tells the immune system to attack more. The wall of the intestine becomes more damaged. More bacteria can get in.

It becomes a vicious cycle that can lead to the symptoms of IBD. (6, 23, 24)

Unhealthy Gut Bacteria Interact with ATG16L1

It sounds kind of crazy, but some white blood cells have to be able to “swallow” bad bacteria before they can kill them. (If you’ve never seen a white blood cell gobble up a bacteria to kill it, you should check it out on YouTube. It looks really cool!)

One of the proteins these immune cells need to be able to “gobble up” bacteria is ATG16L1. If the gene that encodes for this protein is mutated (which it often is in IBD), ATG16L1 can’t do its job. This means that immune cells can’t “eat up” bacteria very well.

If unhealthy gut bacteria trigger immune cells to try to “eat” them, but the immune cell can’t because of a mutated ATG16L1, it has to resort to plan B. Plan B, unfortunately, is really bad for developing IBD.

Immune cells that can’t “eat” bacteria start spewing as many inflammatory chemicals as they can to try to kill the bacteria anyway. These inflammatory chemicals damage the wall of the intestine.

Just as we saw with NOD2, this damage can create a vicious cycle.

More bacteria get into the intestinal wall where it is damaged. These bacteria, who aren’t supposed to be there, activate new immune cells, which try to “eat” them. They can’t, of course, so these immune cells release more inflammatory chemicals. And on it goes. (6, 24, 25)

Unhealthy Gut Bacteria Make Toxins

Some of bacteria that are found in high numbers in the digestive tract of those with IBD can make gut-damaging toxins.

For example, two kinds of bacteria, called D. piger and B. wadsworthia, found at abnormally high levels in IBD, make a chemical called hydrogen sulfide. Hydrogen sulfide is a strong acid that can damage the walls of the intestine. (26, 27)

And, as we saw above, damaging the walls of the intestine can lead to inflammation of the gut wall and IBD.

Unfortunately, it is difficult to tell if you have hydrogen sulfide producing bacteria in your gut, especially your small intestine. Tests for unhealthy bacteria in your large intestine may pick up these toxin-producing bacteria, but a SIBO breath test can’t (yet, at least).  (28)

This makes hydrogen sulfide a potentially potent driver of IBD. Left undetected, this acid can damage gut walls for long periods of time, making it even more likely that the gut inflammation will progress to IBD.

Unhealthy Gut Bacteria Lead to Leaky Gut

Healthy bacteria produce molecules that help the intestinal wall stay strong and healthy. They do this by helping the cells that make up the wall of the intestines produce something called “tight junction proteins.” These proteins seal up the gaps between individual cells to create a seamless wall of cells, with no holes or gaps.

Unhealthy gut bacteria, on the other hand, don’t make enough of the chemicals that help the gut wall make tight-junction proteins. And without enough tight-junction proteins, holes and gaps can start forming in the intestinal wall, leading to a condition called “leaky gut”.

Once your gut is “leaky”, bacteria get through into your body and wreak havoc. They cause the immune system to go nuts, releasing inflammatory chemicals into the intestinal wall and bringing us into the vicious circle of IBD. (29)

Unhealthy Gut Bacteria Cause an Inflammatory Storm

Healthy gut bacteria make a group of chemicals called short-chain fatty acids (SCFAs). SCFAs have an important job in regulating the immune system. They help a group of immune cells, called T-regulatory cells, mature and function.

Mature T-regulatory cells do exactly what their name sounds like they do — they regulate the immune system. Specifically, they help turn off cells that release inflammatory chemicals, such as those damaging the gut wall in IBD.

Unhealthy gut bacteria do not make as many SCFAs, leaving the immune system with fewer T-regulatory cells. This makes it much harder to stop inflammatory chemicals from damaging the intestinal walls and stop IBD from progressing once it starts. (6, 30, 31)

Taking the Bacterial Finger Off the Trigger

Clearly, having unhealthy gut bacteria can be bad news when it comes to developing IBD.

If you have a genetic risk (a close family member who’s already been diagnosed, for example), is there anything you can do to prevent unhealthy gut bacteria from pulling the IBD trigger on you?

Research shows that there are a few things you can to do support healthy gut bacteria and potentially prevent IBD. These include:

  • Quit smoking — cigarette smoke harms your healthy gut bacteria. (13, 14, 32)
  • Limit alcohol intake — excessive amounts of alcohol can harm your healthy gut bacteria. (33)
  • Reduce the use of NSAIDs — NSAIDs can damage the walls of your intestines, making it more difficult for healthy gut bacteria to survive. (13, 34)
  • Eat lots of fruits and vegetables —  fruits and veggies are rich in fiber and prebiotics, both of which help support healthy gut bacteria. (12, 13)
  • Increase your intake of fermented foods or probiotics — These contain healthy gut bacteria which help support the immune system.  (35, 36, 37)
  • Get regular exercise — exercise helps healthy gut bacteria thrive. (38)
  • Drink enough water — proper hydration helps to prevent constipation, which can have negative effects on your gut bacteria can keep your healthy gut bacteria from growing properly. (39, 40)

If you know you are at risk for IBD or have already been diagnosed with IBD, you should absolutely test your gut microbiota.

Testing can identify unhealthy levels of gut bacteria that need to be treated more aggressively with antibiotics or antibiotic herbs.

Un-Firing the Bullet

What if you already have IBD? Can addressing poor gut bacterial health also address your IBD symptoms?

Research shows that fixing imbalanced gut bacteria can help IBD symptoms, but not always. We need more studies to be done in this area, but the current research shows that the beneficial effects of fixing imbalanced bacteria depend on both the type of IBD and the type of treatment used to balance unhealthy bacteria. (6, 41)

But a few treatments seem to be helpful for IBD patients, which I’ll go over below.

Researchers wondered the exact same thing and put it to the test. (6, 41)

Ulcerative Colitis Treatments

Studies show that treatment with the probiotics VSL#3 and E. coli Nissle 1917 are the most helpful bacterial-treatment option.

These probiotics contain purified strains of healthy gut bacteria and have been shown to improve the symptoms of ulcerative colitis better than placebos in multiple studies. (6, 42, 43, 44, 45, 46)

Ulcerative colitis symptoms may also respond to treatment with germinated barley foodstuff, a prebiotic.

Healthy gut bacteria can use germinated barley foodstuff for food and fuel, helping them get the upper hand on unhealthy gut bacteria and regain normal ratios. (6, 47, 48, 49)

Given the response to this particular prebiotic, it would make sense to suspect that other prebiotics, like FOS or GOS, may be useful, as well.

Crohn’s Disease Treatments

Studies show that fecal transplants can be very beneficial for Crohn’s disease patients. (6, 50)

Fecal transplants are medical procedures that do exactly what they sound like. Doctors use stool from a healthy donor without IBD, blend it, filter it and introduce the filtered liquid into the gut. This can be done via an enema, a colonoscopy or a tube threaded through the nose and throat into the gut. (6)

Studies show that fecal transplants are very effective at treating Crohn’s disease symptoms for months at a time. This is mostly true for those who have Crohn’s disease and an intestinal infection with a pesky bacteria called C. difficile. (6, 51)

Treatment Safety

While doctors and scientists believe that prebiotics, probiotics and fecal transplants are generally safe to use, they are not entirely without side effects. (6)

Most side effects are mild and include things like gas, bloating, or diarrhea. Not great when you’re trying to treat digestive issues, but not life-threatening. (6)

In those with IBD, however, there is a slight risk that probiotics and fecal transplants can lead to a very serious side-effect: blood poisoning. (6, 52, 53)

Both probiotics and fecal transplants contain live bacteria that can, in rare cases, get through the damaged gut wall in IBD and into the bloodstream. This is extremely dangerous. It can cause septic shock and death if not treated quickly and properly. (6, 52, 53)

For this reason, it is important that those with IBD discuss all treatments for unhealthy gut bacteria with their doctor and only take over-the-counter supplements under their doctor’s supervision.

Healthy Gut Bacteria: A Magic Bullet?

Even a couple of decades ago, no one imagined that gut bacteria could play such an important role in the development of IBD. Nor would anyone have imagined that the painful, debilitating, sometimes life-threatening symptoms of IBD might be cured with simple, easy treatments to address gut bacterial health.

While that is not yet a reality for everyone — there is no single magic bullet cure for IBD in treating unhealthy gut bacteria — researchers, doctors, and patients are starting to imagine it!

Maybe, with continued research, those dreams just might come true.

Have you been diagnosed with IBD? Have you tried balancing your gut bacteria to help your IBD symptoms? Let me know in the comment section below!

Does Imbalanced Gut Bacteria Influence Psoriasis?

psoriasis microbiome gut bacteria

Psoriasis is a common immune-mediated condition affecting between 1% and 4% of the population. (1)

The defining characteristic of psoriasis is a unique patchy skin rash. The rash is made up of one or more individual “psoriatic plaques”, which are areas of thickened, inflamed skin covered by a layer of silvery-white flakes. (1)

These plaques burn, sting and itch. In some cases, the itching is severe enough to cause people to scratch the plaques open. The resulting wounds may bleed, ooze, scar or even become infected. (1)

In addition to these serious skin symptoms, psoriasis has many less visible effects. These include (1, 2, 3, 4, 5, 6):

  • social ostracization by those who believe psoriasis is contagious
  • changes in personal and intimate relationships
  • loss of a healthy social life
  • development of chronic joint inflammation (“psoriatic arthritis”)
  • development of clinical depression, anxiety, & suicidal thoughts
  • increased risk for metabolic syndrome (obesity, diabetes, high blood pressure)
  • increased risk for inflammatory bowel disease (Crohn’s disease, ulcerative colitis)
  • severely decreased quality of life

Current Psoriasis Treatments

Thankfully, there are many treatment options available to help people manage the many symptoms of psoriasis. Light treatments, medicated ointments, steroid creams, prescription pills and injections can all be effective in helping minimize psoriasis’ effects on a person’s life. (1)

However, none of these treatment options is without its downsides.

Topical skin treatments aren’t always strong enough to really heal psoriatic plaques and can’t address non-skin symptoms. (1, 7)

Immune-modulating pills and injections are more effective when the skin rash is severe and they can provide relief for whole body symptoms. But they can also cause serious side effects and can cost a small fortune. (1, 8, 9, 10)

These downsides have left patients and researchers looking for more effective, safer and cheaper options. (4)

Recently, there has been growing hope that efforts to support healthy gut bacteria might provide just that. (11, 12, 13, 14)

Where has this hope come from?

To understand the answer to this question, it is useful to take a quick step back and review exactly how psoriatic plaques develop in the first place.

Immune Dysfunction in Psoriasis

When the immune system is healthy, immune cells patrol the skin for wounds, infections and cancer. These immune cells communicate with each other, sending signals to one another to ensure that they all attack when there is danger and no one attacks when there isn’t. (15, 16, 17)  

Researchers believe that in people with psoriasis this communication between immune cells breaks down. Specifically, one group of immune system regulating cells, called T regulatory cells (Treg for short), loses its ability to control another group of inflammation-promoting immune cells, called Th17 cells. (15, 16, 17)

Treg cells regulate the immune system and keep other inflammatory immune cells like Th17 from wreaking havoc.

Th17 cells release inflammatory chemicals and oxidants into the skin around them, harming or even killing the skin cells they come into contact with. This leads to pain, swelling, redness, and itching and a build-up of silver-white dead skin cells. (15, 16, 17, 18)  

Unfortunately, once Treg cells lose control of Th17 cells, it’s difficult to ever get them under control again.

This is because the same chemicals damaging the skin also draw new Th17 to the skin and tell them to start making even more inflammatory chemicals. This creates a vicious cycle, with ever more Th17 cells arriving and overwhelming any effort by Treg cells to bring them back under control. (15, 16, 17)

Immune Regulation and Gut Microbiota

So why might changes in gut bacteria be helpful in breaking this cycle?

Well, there is growing evidence that healthy gut bacteria do something remarkable: They increase the function of Treg cells and decrease the function of Th17 cells. (19)

This is exactly what we’re looking for when trying to control an autoimmune response.

Helping Treg cells control Th17 cells while simultaneously making the Th17 cells less powerful gives Treg cells a fighting chance to get the upper hand again and stop Th17 cell attacks on the skin altogether.

Boosting Treg Function

Healthy gut bacteria provide a double boost to Tregs’ ability to stop Th17 cells. They can enhance Treg cell function directly and increase the number of Treg cells you have.

Improving Function Directly

Healthy gut bacteria make a group of chemicals called short-chain fatty acids (SCFAs) (19, 20, 21), which are powerful modulators of Treg cells. SCFAs enter the cells and make their “stop attacking” signals stay turned on, halting the attack on your skin. (19, 20, 22)

This ensures that Treg cells can produce and send tons of these regulating signals out to Th17 cells. The more signals make it to attacking Th17 cells, the more likely they can all be brought back under control.

Increasing Treg Numbers

In addition to making each Treg more efficient at producing regulatory chemicals, healthy gut bacteria also help increase the number of active Treg cells in the body.

This they do indirectly by boosting the functions of a different group of immune cells, called dendritic cells. (19, 23, 24)

Dendritic cells are responsible for sending signals to immature Treg cells that it’s time to “grow-up” and start controlling Th17 cells. (19, 24)

Remember the SCFAs that keep the “stop attacking” signal turned on in Treg cells? Well, those same SCFAs also help to send this “grow up” signal to immature Treg cells from dendritic cells.   

Interestingly, SCFAs aren’t the only molecules made by these healthy bacteria that have this boosting effect on dendritic cells — they also make a molecule called histamine, which stimulates dendritic cells to make more of the chemicals that allow Treg cells to mature. (19, 25)

Studies also show that dendritic cells are healthier, in general, when beneficial gut bacteria are around. This appears to be the result of an increased ability of dendritic cells to make their own vitamin A when healthy levels of these bacteria are in the gut. (19, 26)

Vitamin A is a powerful hormone that dendritic cells need to function properly. By increasing vitamin A levels, gut bacteria help ensure that Treg-cell stimulating dendritic cells are healthy, happy, and functioning optimally. (19, 27)

Hampering Th17 Function

The SCFAs and histamine produced by your healthy gut bacteria have another beneficial effect when it comes to controlling the autoimmune process: they slow down the production of inflammatory chemicals by Th17 cells. (19, 28, 29, 30)

These inflammatory chemicals are responsible for the swelling, pain, redness, itching, and other symptoms you get when you have psoriasis. (15, 16, 17, 18)

Healthy bacteria keep these inflammatory chemicals in check, thus keeping your skin healthy.

Getting Healthy Levels of Good Gut Bacteria

Clearly, improving the health of your microbiome can be useful in helping the immune system regain its balance and keeping psoriasis away for good.

If you’ve been diagnosed with psoriasis, I highly recommend testing your gut bacteria to see if you may have a microbiome imbalance, such as dysbiosis or small intestinal bacterial overgrowth (SIBO).

Both dysbiosis and SIBO have been linked to the development of psoriasis. In addition to this, more severely imbalanced bacteria correlates to worse psoriasis symptoms, and treating SIBO or dysbiosis is associated with improved psoriasis symptoms. (12, 31, 32)

If you have psoriasis and one of these gut bacterial imbalances, you want to find out and get it treated!

You can use a breath test to determine if you have SIBO, or a stool test to identify any bacterial colonies that are out of place in the large intestine. You can learn more about testing here.

If you discover that you have SIBO or dysbiosis, it’s very important to balance your microbiome using antimicrobial herbs, antibiotics, probiotics, prebiotics and more. This, in turn, will help to regulate your immune system!

Beyond identifying and dealing with any imbalances in your microbiome, you can also make some dietary and lifestyle changes that will help to balance your gut bacteria as well. Some of these changes include:

Increasing Probiotic Intake

Probiotics are really amazing in their ability to help regulate the immune system and have been shown to have positive effects on psoriasis symptoms and biomarkers. (33, 34)

Regularly consuming fermented foods like kimchi, sauerkraut, yogurt and kefir is a great way to get these helpful bacteria into your system. (35, 36)

You can also take a probiotic supplement to get these beneficial bacteria if you’re not a fan of fermented foods. (37)

Boosting Prebiotic and Fiber Intake

Healthy gut bacteria use prebiotics and fiber to survive, grow, thrive and make SCFAs. (38) Increasing fiber intakes can boost their levels and function in the gut within just a few days! (39)

Easy ways to increase fiber intake include loading up on fiber-rich foods, such as fruits and vegetables, or taking a fiber supplement. (37)

Getting Enough Exercise

Studies show moderate aerobic exercise can increase the health of your gut bacteria. (40) The introduction of a regular exercise routine has also been shown to be useful in easing psoriasis symptoms.  (41, 42, 43)

Drinking Enough Water

Dehydration can mess with your gut bacteria by promoting constipation. (44) Constipation slows down the movements of your intestinal wall. This can affect how well gut bacteria grow and lead to poor gut bacterial health. (45, 46)

Shifting to a Whole Foods Diet

Study after study shows that a western style diet rich in calories, fat, simple sugars, and salt and low in fruits and vegetables is harmful to healthy gut bacteria, while traditional diets rich in whole foods help these bacteria grow. (47, 48, 49, 50)

Multiple studies also show that putting individuals with psoriasis on a whole-food diet can improve their symptoms. (41, 42, 43)

The Impact of Diet on the Immune System

Diet plays a crucial role in regulating a healthy immune system and controlling psoriasis.

Evidence suggests that a shift away from processed foods towards whole foods may not only boost fiber intake, healthy gut bacteria numbers, SCFA levels and histamine levels, but it might very well provide its own direct inhibition of Th17 cells.

Th17 Function and Processed Foods

There are at least two components in processed food that may boost Th17 function: salt and advanced glycation end products.


While I’m not against a moderate amount of salt in the diet (and in fact higher levels of salt intake can be helpful in conditions like “adrenal fatigue”), research indicates that the high level of salt found in many processed foods is problematic when it comes to autoimmune disease.

Consuming large amounts of salt directly activates Th17 cells, which produce inflammatory chemicals and in turn lead to psoriasis symptoms.

Researchers have recently identified a special sensor in Th17 cells that is sensitive to the amount of salt around. If this sensor is activated by lots of salt, it causes the Th17 cells to produce more inflammatory chemicals. (51)

And this isn’t just at the cellular level. Studies show that eating diets containing lots of salt leads to worsening of symptoms of Th17-related diseases, such as asthma and multiple sclerosis. (52, 53, 54, 55)

Advanced Glycation End Products (AGEs)

Advanced glycation end products (AGEs) form when foods are heated to extreme temperatures, making them a common molecule found in broiled or fried foods like chips, french fries, chicken nuggets, fish sticks, etc. (56, 57)

Similar to how SCFAs and histamine help Treg cells mature, AGEs have been found to help inflammation-promoting Th17 cells mature. (58) This suggests that eating lots of fried junk food can increase the number of damaging Th17 cells.

Th17 Function and Whole Foods

On the other hand, replacing junk food with whole foods can help to reduce the damage from Th17 cells.


One nutrient rich in many whole foods that may play an important role in regulating immune function is potassium.

High levels of potassium trigger the kidneys to produce a group of molecules called glucocorticosteroids. (59)

These molecules are natural steroids that work just like the drugs doctors prescribe. They are powerful inhibitors of inflammatory chemicals. (60)

Bioactive Phytonutrients

Many whole plant foods contain phytonutrients that have helpful health benefits. Some of these benefits include preventing the effects of inflammatory chemicals on the body. (61, 62, 63)

Some of these anti-inflammatory phytonutrients have powerful effects against inflammatory chemicals known to be important in damaging psoriatic skin.

For example, there is a phytonutrient in turmeric root called curcumin that blocks the effects of the inflammatory chemical TNF-alpha, which plays a major role in promoting psoriasis. (64, 65) In fact, curcumin blocks TNF-alpha nearly as well as drugs we designed to block it. (66)

In addition to the anti-inflammatory nature of phytonutrients, polyphenols (a type of phytonutrient) also boost the health of your microbiome. If you’d like to learn more about that process, check out my article on the topic here.


As their name suggests, antioxidants block the effects of oxidants.

Since one of the key chemicals Th17 cells use to damage skin cells are oxidants (called reactive oxygen species (ROSs)), antioxidants from fruits, vegetables, nuts, seeds, teas and spices may be helpful in reducing psoriasis symptoms. (18, 67, 68, 69, 70)

The Bottom Line:

The evidence suggests that a whole food diet rich in foods that help promote a healthy microbiome may help prevent and reduce the symptoms of psoriasis and other autoimmune diseases.


Have you been diagnosed with psoriasis? Do you notice a difference in your symptoms when you eat well and support your microbiome? Let me know in the comment section below!

Is a High-Fat Diet Bad for Your Microbiome?

You probably know by now that the health of your microbiome strongly influences the health of the rest of your body.  

Healthy gut bacteria promote digestive health, metabolic health, immune health, mental health and cardiovascular health. (1, 2, 3, 4) Unhealthy gut bacteria do the opposite, promoting a whole host of serious diseases, including anxiety, depression, obesity, infertility, polycystic ovary syndrome, autoimmune diseases, diabetes, heart disease, dementia, and cancer. (1, 2, 3, 4, 5, 6, 7) But what determines the health of your gut bacteria?

Factors That Lead to a Healthy Microbiome

There are many factors that play a role in a developing (and maintaining) a healthy microbiome. These include:  

  • Genetics (8)
  • Exposure to tobacco smoke (9)
  • Use of prescription, over-the-counter or recreational drugs (10, 11, 12)
  • Exposure to pesticides, detergents and industrial chemicals (13, 14)
  • Amount of daily physical activity (15)

One of the most important factors, however, is your daily diet.

Different types of diets promote different balances of gut bacteria — some are healthier, while others aren’t. (16, 17, 18, 19, 20, 21).   

And these changes in microbial balance can happen quickly — switching from diet to diet over a short period of time (from a day to a couple of weeks) is sufficient to significantly change the health of your gut bacteria. (22, 23, 24, 25)

It might seem odd that something as simple as food could have such a profound impact on the bacteria that play such a critical role in keeping you healthy. You’d hope that your bacteria would be pretty stable and keep working away to maintain your health, day-in, day-out, regardless of the food you eat.

But when you really think about it, it makes sense. After all, your gut bacteria come into direct contact with the food you eat, 3 times a day (or more!), every day. The food you eat (and its nutrients, contaminants, or toxins) can easily influence your bacteria’s normal biological and metabolic processes and, in turn, their overall health.

I’m often asked what the best macronutrient ratio is for gut health. Research has shown time and again that complex carbohydrates and fiber help to boost the health of your microbiome, while large amounts of sugar and fat have negative consequences on the health of your bacteria.

It’s easy to understand why carbohydrates and fiber are healthy for your gut bacteria since they are what your microbes feed on, but what causes a lot of confusion (and controversy) is the amount of fat that promotes a healthy microbiome.

So today, I’m going to focus on fat: how much is too much when it comes to gut health?

High-Fat Diets & Gut Bacteria

I’ll be the first to admit that I was a bit skeptical when I came across research that implicated high-fat diets as one of the causes of unhealthy gut bacteria. After all, I’m very much a “real foodie” and don’t shy away from recommending fats as a major component of a healthy diet.

But I kept seeing more and more research about fat and its negative impact on the health of the microbiome, and it became clear that I needed to investigate this further.

Truth is, there is a lot of research behind this idea and it’s pretty strong. Every type of study that’s been used — animal models, epidemiological studies, and human intervention studies — all show that your gut bacteria change in response to consumption of a high-fat diet. (16, 17, 22, 23, 26, 27, 28, 29) What’s more, the changes found by these diverse methodologies are, generally, very similar. (16, 17, 22, 23, 26, 27, 28, 29)

So what are those changes, exactly?

A high-fat diet appears to induce very specific changes in the ratios of the bacteria in the gut — high-fat diets are able to decrease the numbers of healthy gut bacteria while simultaneously increasing the numbers of less healthy gut bacteria. (16, 17, 22, 23, 26, 27, 28, 29)

This imbalance (a state referred to as dysbiosis), is an unhealthy situation for your gut bacteria, your gut, and you. It has been associated with gastrointestinal diseases, low-grade systemic inflammation and all of those serious conditions mentioned above. (1, 2, 3, 4, 5, 6, 7, 30)

Of course, this begs the question: Why? Why does a high-fat diet cause your gut bacteria to go so out of whack?

While we don’t know for sure yet (and there are many factors at play), there seem to be three main processes involved.

Let’s explore them one-by-one.

Increased Production of Bile Acids

Bile acids are molecules made by your liver to help your body digest and absorb fat. They work as a type of natural emulsifier, allowing fat from your food to mix into your water-based digestive fluids. This allows the fat you eat to come into contact with the necessary digestive enzymes to actually be broken down and absorbed.

Since bile acids are so important for being able to absorb fat efficiently, your body has an elegant system for making sure there are enough bile acids for all the fat from your food. When fat molecules, particularly big, bulky monounsaturated and polyunsaturated fat molecules, are detected by the cells lining the walls of your intestines, they begin producing a hormone called CCK. (31, 32, 33)

CCK is released in your bloodstream and is transported to your gallbladder, the small sack-like organ which stores bile acids from your liver until you need them. CCK tells your gallbladder to contract, causing the bile acids to be released out into your intestines. There, they can be used to help you absorb the fat you’ve eaten.

The greater the amount of dietary fat, the more CCK made, and the more bile acids released.

Okay, but what does any of this have to do with your gut bacteria?

Well, it turns out that some species of gut bacteria use bile acids to make antibiotics that kill off their neighbors. (22, 34, 35, 36) It’s a useful little trick for them, helping them make sure no one invades their patch of intestinal wall.

When produced in normal amounts in response to a moderate fat diet, these antibiotics help to ensure that the ratios between different species of bacteria in your stay balanced by preventing certain species from growing out of control.

However, high-fat diets produce high concentrations of these antibiotics, which can cause imbalances in bacteria to develop. When too many of these crafty bacteria’s neighbors are killed off, their populations may drop to unhealthy levels.

Researchers suspect that this might be exactly what happens in those eating a high-fat diet, and it may be one of the main reasons for the high-fat-diet-associated unhealthy changes in gut bacteria. (22)

Increased Absorption of LPS

Another mechanism strongly suspected of underpinning the relationship between high-fat diets and poor gut bacterial health is an increased absorption of a toxic molecule called lipopolysaccharide (LPS).

While “leaky gut” or intestinal permeability is the main way large amounts of toxic LPS get into your body, it turns out that small amounts of LPS are regularly transported through an entirely healthy gut wall by little transport vehicles called chylomicrons. (37, 38, 39)

Chylomicrons are small, round packages made by your body to hold digested long-chained dietary fats. They are responsible for transporting these fats through your intestinal wall and taking them to your liver for proper processing and re-packaging for transport to the rest of your body.

If you consume greater amounts of dietary fat, your body has to produce more chylomicrons to transport them all. The more chylomicrons, the more LPS can be accidentally packaged up with the dietary fat and absorbed into your body.

When LPS gets into your body, your immune system immediately (and accurately) recognizes it as dangerous and mounts an attack. (40, 41, 42) Your immune cells begin producing all kinds of inflammatory chemicals intended to help fight off any intruder and begin pumping them into your bloodstream.

These inflammatory chemicals signal to your gut that there danger is present, which in turn leads to changes in the walls of your intestine that affect how well your gut bacteria survive. (43, 44) Eventually, this leads to the development of dysbiosis, or the imbalance of good and bad bacteria in the gut.

Decreased Intake of Complex Carbohydrates

The final mechanism currently believed to play an important role in linking high-fat diets to changes in gut bacterial health is very indirect, but may ultimately prove to be one of the most important.

By definition, a high-fat diet must contain a lower percentage of calories from carbohydrates and protein. Researchers think that the drop off in the intake of these macronutrients, particularly complex carbohydrates, may be responsible for the development of dysbiosis. (45)

See, many gut bacteria use dietary fiber — sugar complexes made by plants that your body cannot digest — as their primary (or only) food source. (46) Without enough fiber, these species may fail to thrive. And in fact, we see significant improvements in gut health when bacteria have plenty of fiber to consume. (26, 45, 46, 47)

Problem is, nearly all high-fiber foods are also carbohydrate-rich (with the exception of foods like coconuts, avocados, and nuts). So those who follow a high-fat diet are mostly missing out on these high-fiber choices, especially if they are eating a Standard American Diet that consists of lots of processed junk food. Without the healthy fiber found in carbohydrate-rich foods, your gut bacteria suffer. (45, 48)

Are All Fats Bad for Gut Health?

When we dive into the research, there are clear hints that the type of fat, not just the amount, plays a key role.

For example, omega-3 fatty acids (found in fish) have been found to induce positive changes in the microbiome, while omega-6 fatty acids (found in industrial seed oils like canola oil) have a damaging effect. (49, 50)

As discussed earlier, the production of CCK stimulates the release of bacteria-harming bile acids. But CCK is produced much more efficiently in the presence of unsaturated fatty acids. This suggests that replacing some of these unsaturated fats with saturated fats may protect your gut bacteria. Since omega-6 fatty acids (a type of unsaturated fat) have proven harmful to microbial health, it makes sense to take some of these out and swap them for saturated fats.

Compared to omega-6 fatty acids, saturated fats do not cause nearly as much damage to the gut. (51)

But you also don’t want to overdo it. Switching to a diet containing primarily saturated fatty acids may end up harming your gut bacteria too.

There are a couple of reasons for this.

First, CCK produced from unsaturated fatty acids is also responsible for transmitting a key “I’m full” signal to your brain. (33) Without it, it becomes a lot easier to overeat. And overeating –regardless of macronutrient content– can harm your gut bacteria. (52)

Additionally, saturated fat may be less easily absorbed in your small intestine (perhaps as a result of less CCK and bile acid release). Studies indicate that if a diet contains too much saturated fat, the small intestine may not be able to absorb it all and some of the fat can make it into your colon and disrupt the delicate balance between the species of healthy gut bacteria. (53)

Finally, at higher concentrations, saturated fatty acids have been shown to be able to trigger an immune response by binding to a receptor on some of your white blood cells called TLR-4.

Similar to the effect seen when LPS triggers an immune response, immune cells activated by saturated fats release inflammatory chemicals that change how the walls of your intestines function, altering how well your gut bacteria survive. (54)

A happy medium may be to reduce your intake of omega-6 fatty acids from industrial seed oils and include some monounsaturated fats in your diet so that you have a healthy amount of CCK production, while still reducing the overall amount of omega-6 fatty acids that you consume.

Monounsaturated fat (like that found in olive oil), has been shown to mitigate the damage done by high-fat diets. (55) Scientists believe that some of the beneficial effects of olive oil may actually come from its polyphenols, as research indicates that virgin olive oil has a much more protective effect than refined olive oil. (56)

Given everything we know about how different types of fats affect the microbiome, it makes sense to avoid industrial seed oils (omega-6 fatty acids) and eat a mix of monounsaturated and saturated fats, with small amounts of omega-3 fatty acids coming from foods like fish and nuts. In this sense, the real food movement strikes a great balance when it comes to consuming the proper balance of fatty acids for gut health.

Do I Need to Eat a Low-Fat Diet to Have Healthy Gut Bacteria?

Interestingly, the negative consequences of a “high-fat” diet only happen when you start eating approximately 42% to a whopping 70% of your calories as fat

Moderately high-fat diets (35% or less calories from fat) do not show these same effects. (39)

That means that if you’re eating a 2000-calorie diet, you can have up to 78 grams of fat per day with no negative consequences to your microbiome.

Eating a calorically-appropriate diet is vital since overeating harms gut bacterial health as well.

On top of that, it’s important to eat the right types of fats. As I discussed previously, I believe consuming mostly monounsaturated and saturated fats with small amounts of polyunsaturated fats from fish and nuts is the right approach here. The key is to avoid high amounts of omega-6 fatty acids.

To review, here is what we currently know about the best diet to support your microbiome:

  • Eat a moderate fat diet (<35% of calories from fat)
  • Eat an appropriate amount of calories overall
  • Avoid industrial seed oils (like vegetable oil) and aim for a mix of monounsaturated and saturated fats, with small amounts of polyunsaturated fats from fish and nuts
  • Choose high-fiber carbohydrate foods

What If I Want to Eat a High-Fat Diet?

There are probably some of you reading this article who know you do best with a high-fat diet. You might have diabetes and a low-carb diet keeps your glucose levels normal, or perhaps you’re using a ketogenic diet to help manage a condition like epilepsy.

If this is you, don’t worry! There are ways to mitigate the negative microbial effects of a high-fat diet.

Here’s what the research says:

  • Eat enough fiber from the foods you can eat. If you’re following a high-fat diet, this means making sure you’re eating tons of fibrous veggies, berries, avocados, nuts and seeds that fit within you plan. Eating lots of plant matter also helps you consume plenty of polyphenols which have a protective effect on your gut bacteria as well. (57, 58)
  • Take prebiotics. Prebiotics have been shown to protect gut bacteria from the negative effects of a high fat diet. (59, 60)
  • Take probiotics. Much like prebiotics, probiotic supplementation can attenuate the negative impact of a high fat diet. (61, 62, 63)

Just as you should when following a moderate-fat diet, you should also consume an appropriate amount of calories and eat the right types of fats to promote microbial balance in the gut.

And even if you aren’t eating a high-fat diet, eating high fiber foods and taking probiotics and prebiotics is a great idea to ensure a healthy gut.

The Bottom Line:

Clearly, the relationship between the fat you eat and your gut bacteria is complex.

However, research indicates that a moderate fat diet (<35% of calories) is best, especially when you’re eating fats that are protective of your microbiome (like olive oil and omega-3 fatty acids).

If you want to consume a higher fat diet, choosing these types of fats may keep your gut healthier than if you ate a high omega-6 fatty acid diet. You can also consume prebiotics and probiotics to protect your gut bacteria while on a high-fat diet.

Now I’d like to hear from you: will you be changing your macronutrient intake as a result of the evidence presented in this article?

Can SIBO cause fibromyalgia?

Although fibromyalgia is among the most common causes of chronic, widespread pain (believed to affect an estimated 5 million people in the US alone) it remains one of the least understood. (1, 2)

Researchers generally agree that the key problem in fibromyalgia is a change in how pain signals from the skin, joints and muscles are processed in the brain, leading to the characteristic and diagnostic long-term, body-wide pain. (1, 3) But, to date, no one has been able to definitively prove what causes these changes, and how. (3, 4)

However, growing evidence suggests that fibromyalgia may be caused by poor gut health — specifically, by a condition called “small intestinal bacterial overgrowth (SIBO)”, in which colon bacteria begin colonizing the normally relatively sterile environment of the small intestine. (5)

Let’s explore this growing body of evidence, what it means, and it’s possible implications for ways to address fibromyalgia symptoms.

Fibromyalgia, SIBO and the Breath Test

The most direct, and perhaps the most important, evidence supporting the idea that fibromyalgia may be caused by SIBO came from a 2001 study by researchers at Cedar-Sinai Medical Center which first linked the two conditions. (6) Inspired by epidemiological studies that showed extremely high rates of gut dysfunction in people with fibromyalgia, (7, 8, 9) the researchers decided to look at the state of their intestinal health more closely. Close examination of the epidemiological studies showed that gastrointestinal symptoms reported by fibromyalgia patients were similar to the symptoms seen in Irritable Bowel Syndrome (IBS). (7, 8, 9)

Since previous work in the Cedar-Sinai lab had established strong links between SIBO and IBS, they thought looking for SIBO in fibromyalgia patients may be a smart place to start. (10)

So, they put it to the test!

They organized a group of 123 volunteers with fibromyalgia to undergo SIBO breath testing. Results showed that nearly 80% of the group tested positive for SIBO, a much higher rate than seen in healthy groups of volunteers, or even in groups of individuals with IBS. (6)

Though not conclusive proof of a direct link, this data was a huge tip-off that it might be a relationship worth looking into further.

Does SIBO Cause Fibromyalgia?

To determine if there was a causal relationship between SIBO and fibromyalgia, researchers set up an experiment that compared markers of SIBO severity to markers of fibromyalgia severity. If one condition causes another, generally you would expect that increasing the severity of that condition would directly cause a worsening of the other.

As a marker for SIBO severity, researchers used the amount of hydrogen detected in a SIBO breath test. Since the hydrogen detected in the test is made by the bacteria in SIBO, greater levels of hydrogen generally indicate greater numbers of bacteria. And as a marker of fibromyalgia severity, they used self-reported pain levels. (5)

When the data was analyzed, they found that, consistent with a causal relationship, greater levels of hydrogen production were associated with greater reported pain levels. (5)

Now the question remained: did SIBO cause fibromyalgia or did fibromyalgia cause SIBO?

In order to figure this out, researchers took a step back and took a look at all the evidence linking gut health, gut bacteria, brain function and pain regulation and asked themselves: which direction makes more sense? Which one does the scientific literature support more?

The clear answer here was — SIBO is more likely to cause fibromyalgia than the other way around. Close examination of all the evidence allowed researchers to find two step-by-step mechanisms by which SIBO could cause the symptoms of fibromyalgia.

Let’s look at them both!

SIBO May Cause a Tryptophan Deficiency

Tryptophan is one of the 20 standard amino acids and your body uses it to help build proteins. It is also absolutely critical for making an important chemical messenger used to carry nerve signals through the brain called serotonin. It is so important, in fact, that changes in tryptophan levels in your body is sufficient to directly change levels of serotonin in your brain. (11)

One of serotonin’s jobs in the brain is to modulate signals that control the sense of pain. (12)  Based on the symptoms of fibromyalgia, it was suspected that serotonin signaling might play a role in the disorder. And, indeed, when researchers compared those with fibromyalgia to those without the pain disorder they found that people diagnosed with fibromyalgia consistently had lower levels of serotonin in their bodies.  (13, 14, 15, 16)

So, how might SIBO be able to lower tryptophan and serotonin levels?

Well, tryptophan belongs to a group of amino acids called “essential amino acids.” This means that your body can’t make tryptophan by itself; you have to get all of it by absorbing it from the food you eat. SIBO can decrease your ability to absorb tryptophan in three ways:

1. By using up tryptophan from your food

Like us, bacteria use tryptophan to build proteins and keep their cell machinery functioning properly. They can even take it out of the food we eat, just like we can. (17) It doesn’t matter when bacteria do this to food in your colon because you’ve already absorbed what you needed while the food was still in your small intestine.

When colon bacteria move into your small intestine, though, like they do in SIBO, they may use up some of the tryptophan before you get a chance to absorb what you need, driving the levels of tryptophan in your body down. (17)

2. By damaging the lining of your small intestine

SIBO can damage the lining of your small intestine, where tryptophan should be absorbed. This damage may make it difficult for your intestines to absorb the tryptophan not snatched up by the bacteria normally. (17)

3. By decreasing sugar absorption

Changes in the function of your small intestine may also be able to decrease the ability of your body to absorb free sugars. Too many free sugars in your small intestine may directly impair tryptophan absorption. (16)

This is because free sugars, particularly free fructose, can react with tryptophan to create sugar-tryptophan complexes. These complexes are too big to be transported through the intestinal wall the way tryptophan normally is, so they can’t be absorbed. (16)

This, of course, may lower the amount of tryptophan absorbed by the body, and, in turn, lower serotonin levels. (16)

This theory of the development of fibromyalgia is supported by epidemiological studies which consistently show that the disorder is overwhelmingly seen in women; around 96% of those with fibromyalgia are women. (13)

Women’s bodies are less efficient at making serotonin out of tryptophan than men’s. This means that women need higher levels of tryptophan from their diets to make the same amount of serotonin. It also means that decreases in tryptophan absorption lead to a drop off in serotonin levels more quickly in women than men. If tryptophan deficiency were a driving cause behind fibromyalgia, one would indeed expect women to be at much greater risk for developing it, which is exactly what we see in the real world. (16)

SIBO Causes Systemic Inflammation

SIBO causes systemic inflammation, boosting levels of inflammatory chemicals throughout your entire body. (18, 19, 20)  

We now know that when these inflammatory chemicals get into the brain, they can directly induce changes in levels of two other chemical messengers believed to be involved in fibromyalgia called glutamate and γ-aminobutyric acid (GABA). (21) People with fibromyalgia have been consistently found to have an imbalance in signals carried by these two chemicals in a specific area of the brain, the insular cortex. (22, 23, 24)

This area is responsible for integrating sensory signals from the skin, muscles and joints of the body, including pain signals (25) and researchers strongly suspect that this imbalance in the insular cortex play a direct role in the pain dysregulation seen in fibromyalgia. (22, 23, 24)

This theory of the development of fibromyalgia is also strongly supported by epidemiological data. Studies consistently find that those with fibromyalgia have marked increases in levels of inflammation and oxidative stress in their bodies, (2, 19, 26) potentially stemming from SIBO.

What to Do if You Have Fibromyalgia

Given all we know about fibromyalgia, here are a few things to do if you want to reduce the symptoms you experience from this disorder:

1. Get Tested for and Treat SIBO

The evidence clearly supports at least getting tested for SIBO if you have been diagnosed with fibromyalgia.

SIBO is usually tested for by measuring the amount of hydrogen and/or methane in your breath over the course of several hours. It’s simple, non-invasive and may be covered by your insurance.

If your SIBO test comes back positive, your doctor may choose to prescribe a course of antibiotics for you which can kill off the bacteria in your small intestine. You can also use antimicrobial herbs to this effect.

SIBO is linked to a variety of medical conditions, so even if it turns out clearing SIBO does not affect your fibromyalgia, it is still something that absolutely should be dealt with.

If you’re interested in learning more about testing for SIBO and using antimicrobial herbs, check out my 8-week Build Your Biome program.

2. Support Healthy Serotonin Production

As discussed above, serotonin is very important when it comes to fibromyalgia. Here are some steps to take that may help support healthy serotonin levels in your brain:

  • Eat a diet full of tryptophan-rich foods, such as walnuts, rice, potatoes and dark chocolate (16)
  • Avoid foods rich in free sugars which might bind and inhibit tryptophan absorption, such as processed foods made with table sugar or high fructose corn syrup (16, 27)
  • Avoid foods containing aspartame, which can make it difficult for tryptophan to get out of your bloodstream and into your brain (16, 27)
  • Exercise regularly; physical activity has been shown to boost serotonin production in the brain and ease the symptoms of fibromyalgia (28, 29, 30)
  • Get outside; exposure to natural sunlight may boost serotonin production (29)

3. Decrease Inflammation and Oxidative Stress

The clear markers of systemic inflammation and oxidative stress in fibromyalgia also strongly suggest that steps to combat them may be useful in addressing fibromyalgia symptoms, even if determined not to be caused by SIBO.

Steps that may be useful in decreasing inflammation and oxidative stress include:

  • Eating a plant-rich diet; plants are rich in antioxidants and anti-inflammatory phytonutrients (27)
  • Avoid smoking and cigarette smoke which has been proven to cause oxidative stress throughout the body (31, 32)
  • Consider taking a CoQ10 supplement, which is a natural compound known to be depleted by oxidative stress and which has been specifically shown to be helpful in fibromyalgia (27)

If you have fibromyalgia, have you been tested for SIBO? Let me know in the comment section below!

Do Gut Bacteria Influence Autoimmunity?

Autoimmune disorders are conditions that occur when the body’s immune system attacks its own healthy tissues. There are many different autoimmune conditions, depending on which healthy tissues are attacked. Some examples include multiple sclerosis, rheumatoid arthritis and lupus.

Autoimmune conditions are often thought of as “rare” (1) because most of the individual disorders affect a relatively small number of people (2). As a disease class, though, autoimmune disorders are actually among the most common conditions in the United States.

In 2012, the U.S. National Institutes of Health reported that a staggering 23.5 million Americans have at least one autoimmune disease. According to the American Autoimmune Related Diseases Association (AARDA), however, even this remarkable number may be significantly too low, since it was calculated using data concerning diseases that are entirely autoimmune mediated. The AARDA estimates that, if all diseases believed to have any autoimmune component were included in the calculation, the real number of Americans affected by autoimmunity may actually be closer to 50 million.

That means that up to 20% of the population — or 1 in every 5 people — may suffer from autoimmune symptoms.

And autoimmune symptoms can be extremely severe. Depending on the tissues being attacked, autoimmune diseases can cause intense pain, disability, loss of quality of life, loss of income, and even promote premature death. (1, 3)  

Genetics are believed to play an important role (4), but so are a wide variety of environmental factors, such as birth-weight, infections, (5) dietary intake of certain compounds (like gluten, mercury or tryptophan), and exposure to toxins from things like cigarette smoke, air pollution and paint thinners.

While all of these factors have interesting implications for the development, prevention, and treatment of autoimmunity, this article will focus on the newly discovered connections between autoimmunity and the health of your gut microbiota.

Not only are these connections now among the most solidly established, (6, 7) they may also ultimately provide some of the most practical opportunities to develop new treatment options, since, unlike many other factors, gut bacteria are relatively easy to manipulate. (8, 9)

To fully understand the links between autoimmunity and gut bacteria, though, let’s first take a quick step back and look at how your immune system normally works, and what researchers now know goes wrong in autoimmune diseases.


If you think about it, your immune system has a really tricky job. It has to scan your whole body all day, everyday and find dangerous bacteria, infectious viruses, and sick or malfunctioning cells and kill them. If it misses any, you may end up with a serious infection or cancer, either of which could kill you — so it really can’t let any slip by!

On the other hand, your immune system also can’t overshoot and kill cells if it’s not positive they are dangerous because if it kills off your healthy cells, your organs can’t work. Of course, that can be fatal as well!

The immune system has to find the perfect balance: find each and every danger while leaving each and every healthy cell alone.

In order to be able to do this, the human body has evolved a very sophisticated network of immune cells that regulate each other directly (via proteins bound to their surfaces) and indirectly (via special hormones called cytokines).

There are hundreds of types of cells involved in keeping the whole immune system working properly, but for the functions that prevent/cause autoimmunity, the relationships between individual members of a family of cells called T-cells are considered among the most important. (6, 7)

There are three key members of the T-cell family: cytotoxic T-cells, helper T-cells, and regulatory T-cells.

  1. Cytotoxic T-cells (Tcyt-cells) are the cells responsible for actually killing a sick or malfunctioning cell once the rest of the immune system has found it.
  2. Helper T-cells (Th-cells), like their name suggests, help the cytotoxic T-cells. They double check that the cell really needs to be killed and gives the Tcyt-cells the “green light” to actually go through with it. They do this both via protein signals on their surfaces and the release of a special mixture of cytokines. Without these signals from Th-cells, Tcyt-cells are pretty powerless.
  3. Regulatory T-cells (Treg-cells) act as a counter-balance to cytotoxic and helper T-cells. Treg-cells use the proteins on their surfaces and a different mixture of cytokines to call off Tcyt-cells and Th-cells from carrying out attacks.

For a long time, researchers thought that under normal circumstances, all Tcyt-cells that recognized healthy cells in your body as dangerous were forced to undergo “apoptosis” (cellular suicide). In healthy people, this system worked perfectly and no self-reactive cells survived. In people who developed autoimmune diseases, however, one (or more) self-reactive Tcyt-cell did not die for some reason, allowing them free-reign to attack their bodies. (2, 10, 11)

Newer research indicates, however, that even in perfectly healthy people, there are always small numbers self-reactive Tcyt-cells that do not undergo apoptosis. They are always present in your body, trying to attack random, healthy organs, but are simply stopped from doing so by constant suppressive signals from healthy Treg-cells. (2, 10, 11) With a normal, healthy balance between Treg-cells and Tcyt-cell/Th-cells, no Tcyt-cells attack any of your healthy cells. This is referred to as the state of self-tolerance.

As you can imagine, though, this set-up to maintain self-tolerance means that even relatively small manipulations in the number of Tcyt-cells/Th-cells or Treg-cells can easily lead to a problem.

If your levels of self-attacking Tcyt-cells/Th-cells increase, or your levels of Treg-cells decrease, you may end up with too many Tcyt-cells/Th-cells and not enough Treg-cells to stop all of them. (6)

If this happens and Tcyt-cells/Th-cells begin killing your healthy tissue, you have, by definition, developed an autoimmune disorder.


So what do your gut bacteria have to do with any of this?

It turns out, a lot.

In fact, if we wanted to go down to the individual protein and cytokine signals, we would probably have thousands of effects and interactions to talk about!

Luckily, all of the effects gut bacteria have on regulating self-tolerance and autoimmunity can more or less be grouped together into two basic effects which we can talk about more generally:

  1. Regulating the ratios of Th-cells-to-Treg-cells in your body
  2. Influencing your risk of developing more self-attacking Tcyt-cells than normal

Let’s look at these one at a time.


Mounting evidence now clearly shows that the types, numbers, and ratios of bacteria in your gut directly influence how many Th– and Treg-cells you have in your body. (6, 7)

Healthy gut bacteria boost Treg-cell levels in your body by helping your immune system decide to turn immature T-cells into Treg-cells. (6, 7, 12)  Studies in mice have shown that healthy gut bacteria increase Treg-cell numbers through their production of a group of molecules called short-chained fatty acids (SCFAs). (13, 14) Healthy gut bacteria make SCFAs when they break down fiber for energy. (6, 15)

SCFAs can be absorbed into the bloodstream and enter immature T-cells which haven’t decided if they are going to be Tcyt-cells, Th-cells or Treg-cells. There, SCFA turn on the genes that turn them into Treg-cells. (13, 16) This leads to a greater number of Treg-cells in the body, decreasing the chances of a cytotoxic T-cell being able to slip past and start attacking your healthy cells.

Unhealthy gut bacteria, on the other hand, can boost the levels of Th-cells in the body, making it easier for Tcyt-cells to attack your body.

For example, studies show that the growth of even one species of unhealthy bacteria (B. adolescentis) in the gut is able to increase the numbers of Th-cells in the blood. (17)

This effect can even occur just from the wrong ratios of normally healthy gut bacteria in the gut! Overgrowth of the normally healthy E. coli species E. coli 2A, for example, has been shown to to boost Th-cell levels. (18)  

Combined, the effects of decreased healthy bacteria, abnormal ratios of healthy bacteria or the growth of unhealthy bacteria in the gut may shift the ratio of Th-cells-to-Treg cells decidedly in the favor of Th-cells. This can make it much more likely that the “attack” signals outweigh the “don’t attack” signals given to your Tcyt-cells, which can ultimately result in the development of an autoimmune disease. (6, 18)


In addition to helping to determine which balance of signals your Tcyt-cells receive, your gut bacteria also influence your risk of producing Tcyt-cells that recognize your body as dangerous in the first place.They do this through their role in helping your intestinal wall maintain normal “barrier function.”

Normally, healthy gut bacteria help create a solid barrier between you and the outside world, letting only small nutrients through, while keeping larger molecules and bacteria out. If your gut bacteria become unhealthy, however, you can develop a condition called a “leaky gut” that allows larger molecules to get into your body. (19)

Though rare, some of the molecules that can leak into your gut may be what researchers call “molecular mimics”. (20)

A “molecular mimic” is a molecule that happens to have a structure very similar to one that naturally exists in your body.

If one of these mimics gets into your body, your immune system correctly recognizes it as foreign and mounts a defense. As part of this defense, new Tcyt-cells are made that specifically recognize the molecular mimic. Unfortunately, these Tcyt-cells may also accidentally also recognize the mimicked molecule in your body, too. (20) For example, certain human retroviruses contain a protein, VP7, that happens to look very similar to a protein found on human pancreatic β-cells called IA-2. If you become infected with VP7, your body may make Tcyt-cells that correctly identify VP7 as dangerous. Unfortunately, they may also recognize IA-2, since it is so similar. If this happens, these Tcyt-cells may begin attacking the β-cells in your pancreas, leading to type 1 diabetes. (21)

By regulating how many foreign molecules get into your body through your intestinal wall (19), your gut bacteria help determine the risk of your immune system coming into contact with a molecular mimic and producing a Tcyt-cell that will attack both the mimic and your own molecule.

The fewer foreign molecules leak into your body, the smaller the chance one that makes it in will happen to look like one of your own proteins. The more molecules that leak in, the higher the risk!

When combined with the fact that the same unhealthy gut bacteria that cause a leaky gut also promote a high Th-cell-to-Treg cell ratio that encourages Tcyt-cells to kill their targets, you can see how poor gut health can put you at serious risk for autoimmunity.


Since poor gut health puts you at greater risk for developing an autoimmune disease, it stands to reason that protecting your gut health is likely a good way to help prevent an autoimmune disease from developing.

Here are some diet and lifestyle changes that have been shown to improve gut bacteria balance:

  • Avoid refined sugars and fats – Both processed sugar and fat can induce dysbiosis and a leaky gut, letting more potentially mimicking molecules into your body. Note that the type of fat seems to be of importance; I discuss this in more detail in this podcast episode.  (22, 23)
  • Eat lots of fiber and prebiotics – Fiber feeds your healthy gut bacteria. It can help prevent or reverse dysbiosis. (24)
  • Eat an abundance of phytonutrient and polyphenol-rich fruits and vegetables – Polyphenols can boost levels of healthy gut bacteria.
  • Drink plenty of water – Staying properly hydrated prevents constipation and constipation can promote the growth of unhealthy bacteria. (25)
  • Exercising regularly – Exercise has been shown to boost levels of healthy gut bacteria in your intestines. (26)

Can improving your gut bacteria balance actually treat autoimmune disorders? Is there any evidence that improving gut health may also be helpful for individuals after they have already developed an autoimmune disorder?

Relatively few studies have specifically looked at treating gut health to improve the symptoms of autoimmune diseases.

However, a few possibly useful dietary and lifestyle changes have already been identified. These include:

  • Eat plenty of fiber-rich foods – Fiber feeds the good gut bacteria that make SCFAs and promote Treg-cell development. (12, 28)
  • Add specific probiotics – Some studies suggest that probiotics containing specific bacteria (B. infantilis, for example), may be able to boost Treg-cell levels (29); ultimately, which supplements might be effective for you would be best determined by examining your gut bacteria and identifying which bacteria are out of balance. (6)
  • Consume vitamin A rich foods or take a vitamin A supplement – There is growing evidence that retinoic acid, a metabolite made from vitamin A in the body, works in conjunction with gut bacteria to help them increase the number of  Treg-cells in your body. (30) I would recommend 5,000 IU per day, and potentially more under the supervision of your doctor or dietitian.

As always, it’s important to consult with your medical provider for any treatments for your autoimmune disease.

If you’d like to learn more about how your diet and lifestyle influence your gut health, I recommend checking out my 8-week online course Build Your Biome.

Are you hopeful that scientists will eventually find a way to cure autoimmune diseases by manipulating gut bacteria? Let me know your thoughts in the comments below!


Does Polycystic Ovary Syndrome Start with Your Gut Bacteria?

Polycystic ovary syndrome (PCOS) is a common hormonal disorder affecting 4-10% of menstruating women (1, 2, 3).

At the heart of the syndrome is the abnormally high production of androgens (male sex hormones) by the ovaries.

High androgen production creates a characteristic clustering of symptoms that define PCOS, which include (4):

  • Excess facial and body hair growth
  • New or worsening acne
  • Irregular menstruation or lack of menstruation
  • Anovulation
  • Infertility
  • Development of multiple small fluid-filled cysts on both ovaries

In addition to serious reproductive symptoms, the syndrome is associated with a high risk of developing life-threatening chronic metabolic conditions, including insulin resistance, type 2 diabetes, high blood pressure and cardiovascular disease (3, 4).

Despite nearly a century of research (5), scientists have struggled to understand the mechanisms that lead to PCOS (3, 4).

What causes the ovaries to start making too many androgens?

How are changes in reproductive function linked to chronic diseases like diabetes or cardiovascular disease?

We simply didn’t know.

But the latest research indicates that we might finally be on the brink of identifying at least one of the root causes of PCOS.

It seems so counterintuitive that one can almost understand why it’s taken a hundred years to discover: PCOS might actually start in your gut (4).  

As crazy as that sounds, the evidence that PCOS is caused by poor gut health is fast becoming overwhelming.

Let’s look at what the research shows us, and how it implicates gut health in the development of PCOS.


Research now shows that PCOS is consistently coupled with low-grade inflammation (4).

The most recent meta-analysis combining the data from over 30 studies found that women with PCOS have, on average, around double the level of key inflammatory markers in their blood compared to women without PCOS (6).

Why is this so important? Two reasons:

  1. It instantly implicated a role for gut health in PCOS
  2. It explained the link between PCOS and the risk for chronic metabolic diseases.

Around the same time, PCOS was linked to low-grade inflammation, there was a flood of new data coming in linking low-grade inflammation to poor gut health and poor gut health to chronic metabolic diseases (7, 8, 9).

The core concept that came out of the studies examining the connections between inflammation, gut health and metabolic disease is the idea that unhealthy bacteria in the gut can cause “leaky gut”, which then allows the passage of immune-stimulating molecules into the bloodstream (10).

Normally, your gut microbiota and your intestinal wall work together perfectly to form a solid barrier between you and the outside world, letting only tiny nutrient molecules into your blood.

When your gut bacteria become imbalanced, however, the walls of your intestine become “leaky”, allowing big molecules that should be kept out to get into your body. Since they don’t belong in your bloodstream, these molecules activate your immune system, causing chronic, systemic inflammation (4, 10, 11).

This chronic inflammation then leads to metabolic disease by inducing insulin resistance (12, 13). Insulin resistance is a condition where the cells of your body don’t respond to the insulin in your blood (14).

Loss of insulin signaling to your cells sets off a chain reaction that ultimately results in hyperglycemia (too much sugar in your blood), hyperinsulinemia (too much insulin in your blood) and hyperlipidemia (too much fat in your blood) (15, 16). All of these are symptoms of metabolic disease.

So, in one fell swoop, discovering that PCOS involved inflammation provided an explanation for why women with PCOS were more likely to experience insulin resistance, diabetes, high blood pressure and cardiovascular disease and suggested that PCOS might involve gut health.


So what are the molecules that pass into your bloodstream when you have imbalanced gut bacteria and leaky gut?

One of the main offenders is a group of molecules called lipopolysaccharides (LPS). As I’ve mentioned before, LPS are molecules that come from Gram-negative bacteria and they have been strongly implicated in inducing the inflammation associated with leaky gut syndrome. Study after study has shown that elevated LPS can lead to chronic inflammation and the development of a wide variety of chronic diseases, from diabetes and heart disease to autoimmune diseases and cancer (17).

To determine if LPS might also play a role in the inflammation seen in PCOS, researchers compared the blood of women who had been diagnosed with PCOS to that of women who had not.  Consistent with the previous research, the women with PCOS were indeed found to have significantly higher levels of LPS-markers in their bloodstreams (18), suggesting that, as with so many other diseases, a leaky gut and elevated LPS may be involved in the development of PCOS.

Interestingly, while examining the women’s blood, scientists noticed that LPS weren’t the only molecules significantly different between the two groups. The blood of women with PCOS also contained abnormally high levels of a class of compounds called advanced glycation end products (AGEs)  (19, 20).  

AGEs are large, complex molecules made by cross-reactions between sugars and proteins that are formed when plant or animal tissues are heated to high temperatures, such as when deep frying, broiling or roasting food (21, 22). Though naturally found in many foods, AGEs are too large to move easily through a healthy gut wall, and their levels are usually fairly low in the body (19, 20).

Intrigued by finding high levels of these molecules in the blood of women with PCOS, researchers decided to take a closer look at AGEs and their potential effects on the body. Their investigations found that, just like LPS, AGEs were able to activate the immune system and trigger inflammation in the body (11).

But that wasn’t all. AGEs were also shown to be able to promote inflammation a second way; they trigger the production of proinflammatory hormones, like tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), from the cells outside the immune system. Scientists discovered that the cells of some organs in your body have a receptor on their surfaces called RAGE (receptor for advanced glycation end products) that, when bound by AGEs, promote inflammation (11).

And here is where scientists knew they were really on to something with AGEs and PCOS. While exploring how RAGE works in the body, researchers found that this receptor is abnormally concentrated in — you guessed it — the ovaries (23). Activation of RAGE in the ovaries was then shown to induce ovarian inflammation and prevent ovarian cells from responding to female sex hormones, particularly luteinizing hormone (LH), properly (21, 24). Since LH is responsible for allowing follicles to mature and ovulation to occur (25), blocking LH signaling by AGEs could directly cause the anovulation and menstrual irregularities seen in PCOS.  


The final piece of the puzzle linking gut health to PCOS fell into place with the realization that chronic inflammation caused by LPS and AGEs can directly lead to elevated androgen levels in the body (4, 26, 27).

As we discussed above, inflammation leads to hyperinsulinemia. Excess insulin has now been shown to be able to drive the ovaries to produce excess androgens. It appears that a special group of ovarian cells, called theca cells, respond to increased insulin by releasing more and more androgens into the blood (26, 27).

Healing PCOS from the Gut

With the final link between insulin and androgen levels, we now have a comprehensive, logical mechanism to explain how PCOS and all its symptoms develop (4). And, as unexpected as it is, it looks like it all starts with dysbiosis, a leaky gut, and the influx of LPS and AGEs into the bloodstream.

Perhaps the most exciting aspect of discovering the causative role of poor gut health in PCOS is the possibility of improving gut health as a potential cure!  

Since this theory is so new, there hasn’t been a ton of research examining the possibility of treating PCOS by balancing the microbiome. But the results of few that have been done suggest that the strategy is promising.

For example, one study placed 23 women with PCOS on a diet containing various amounts of AGEs. The researchers were able to demonstrate that a decreased intake of AGEs leads to lower levels of AGEs, insulin, inflammatory markers and testosterone in the women’s blood (28).

Another study looked at more directly dysbiosis and PCOS. Here, the researchers conducted a double-blind placebo-controlled study with 40 women diagnosed with PCOS. Half the women were given probiotics of healthy gut bacteria that can help heal dysbiosis, while the other half received a placebo. After 2 months, the women taking the probiotics had lower insulin levels than the women taking the placebo (29).

Together, these studies suggest that improving the health of your gut to decrease LPS and AGE absorption may prove a simple and effective way to minimize your symptoms or potentially even cure your PCOS.

So, what steps can you take if you want to improve your gut health and decrease your absorption of AGEs and LPS?

Some useful dietary and lifestyle changes you may consider implementing include:

  • Avoiding AGE-rich foods, such as roasted peanuts, fried or roasted meats or canned foods that have been sterilized by high heat (30).
  • Eating a diet low in refined sugars and fats, as both of sugar and fat can induce dysbiosis and a leaky gut (31, 32); as I discussed in a previous article, the type of fat makes a difference, but I’d still recommend a moderate fat intake for those with metabolic issues and PCOS.
  • Eating a diet rich in fiber; fiber can help prevent or reverse dysbiosis (33) and prebiotic intake can also decrease LPS levels in the blood (34).
  • Exercising regularly, which has been shown to promote the growth of healthy bacteria in your gut (35).
  • Taking a probiotic to help keep your bacterial balance healthy (29, 36).

While these diet and lifestyle changes are a great start to addressing your gut health and associated PCOS, it may also be a good idea to see a practitioner about more in-depth and personalized ways to help you deal with this condition.

Having PCOS is a good sign that you likely have significant dysbiosis. A practitioner would be able to test your microbiota and determine how you should best deal with your microbial imbalance.

If you’d like to dive right into a more comprehensive, systematic approach to addressing microbial imbalances like SIBO or dysbiosis (including testing), check out my 2-month online course Build Your Biome.

If you have PCOS, does this information change how you think about this condition? Let me know in the comments below!

Does Gut Bacteria Impact Your Pregnancy?

Thinking about starting a family?

If so, now is a very important time to consider your own digestive health — it has a much bigger impact on your baby’s health than you might think!

Gut Bacteria is Passed to Your Baby

For decades, conventional wisdom told us that the womb is a sterile environment, devoid of any microbes to protect your baby and its growing immune system. It was thought that your baby doesn’t get exposed to any bacteria until during birth when it passes through the vaginal canal. (1)

But recently, researchers have been able to detect some bacteria in the placenta and even in the intestines of a fetus. (2,3) They posit that this bacteria is derived from your (mom’s) gut microbiome, meaning your gut bacteria can travel via the placenta to reach your baby and affect its development.

So, your baby’s microbiome begins developing and acquiring bacteria from you far earlier than we previously thought.

That makes it even more important that you have the healthiest gut you can prior to getting pregnant — If you have a healthy gut, chances are that your baby will have a healthy gut and a healthy start to life too.

Imbalanced Gut Bacteria Can Complicate Pregnancy

During pregnancy, a woman’s gut microbiome goes through many dramatic changes.

One of these is how a woman’s gut will naturally become dysbiotic (or imbalanced) in her third trimester: certain bacterial colonies become fewer and less diverse, and more bad bacteria are temporarily present.

Specifically, researchers observe increases in the abundance of Proteobacteria and Actinobacteria, which are strains commonly seen in inflammatory bowel disease. (5) It’s thought that this temporary dysbiosis somehow helps prepare mom for birthing, although it’s still not exactly known.

However, what happens if you already have gut dysbiosis before pregnancy? Does this affect the course of your pregnancy?

It’s possible for your gut bacteria to become too dysbiotic by the third trimester if you’re already starting off imbalanced. This imbalance can complicate other essential pregnancy adaptations (i.e. increase in blood volume, altered immune response) and result in gestational diabetes, hypertension, or excess weight gain. (6)

Imbalanced flora is also associated with obesity, increased growth of pathobionts (good bacteria that turn bad), and increased inflammation. (7, 8, 9, 10) These can complicate pregnancies and lead to preterm births or pre-eclampsia, a dangerous condition of high blood pressure during pregnancy. (11)

Furthermore, recall how your gut bacteria can reach the baby via the placenta — dysbiosis and too much of the ‘wrong’ bacteria have been linked to premature rupture of membranes and premature birth, and babies who are born prematurely are more likely to have health issues. (12, 13)

Therefore, it’s important to make sure your gut is well-balanced before pregnancy to set yourself and your baby up for the best possible outcomes!

Weight and its Impact on Gut Bacteria and Metabolic Outcomes for Babies

Being at a healthy weight before becoming pregnant is a great way to help ensure better metabolic health for your baby. (Not sure if you’re a healthy weight? You can use a BMI calculator to gauge where you are).

Dysbiosis is a big problem when it comes to metabolic health (which I’ve discussed before here). When you have dysbiosis, you develop intestinal permeability and chronic, low-grade inflammation that is highly associated with metabolic health issues, such as obesity, insulin resistance, and diabetes.

And not only does obesity impact your own health, but it also has both short- and long-term consequences for your baby. For instance, one study found that the infants of obese mothers had greater percent body fat and had already developed insulin resistance in the womb.

Obese women also have a higher risk of developing pregnancy complications and metabolic diseases, such as increased risk of miscarriage, increased risk of C-section delivery, gestational diabetes, hypertension, and preeclampsia. (16, 17, 18) All of these can greatly compromise infant health outcomes.

Furthermore, starting off with a balanced gut can ensure that your infant will have a healthy metabolic outcome and a normal body weight. To illustrate this point, let’s look at this diagram below:

Source: Gohir, W., Ratcliffe, E. M., & Sloboda, D. M. (2014). Of the bugs that shape us: maternal obesity, the gut microbiome, and long-term disease risk. Pediatric research, 77(1-2), 196-204.


  • (A) depicts a woman with a normal body weight that possesses a stable, healthy gut microbiota which changes over the course of pregnancy.

Women with a normal body weight are more likely to have balanced gut bacteria. It is proposed that this balance helps facilitate normal gut development and function in the baby, and helps the baby regulate a healthy body weight.

  • (B) depicts an obese woman, who is more likely to present with disrupted gut microbiota already before pregnancy. This imbalance is further amplified through the course of her pregnancy.

This imbalance could also lead to poor or altered gut development, adverse metabolic health outcomes, and mediated increased chronic disease risk for the baby.


As you can see, managing your body weight by developing a balanced gut before becoming pregnant is essential to make sure you’re passing down a healthy gut to your baby.

A Healthy Gut Makes For a Healthy Pregnancy

By now, you understand that it is important to start your pregnancy off by having balanced gut bacteria and being at a healthy body weight, both of which go hand in hand.

Here are some steps you can take to make sure you’re passing on a healthy gut microbiome to your baby:

  • Get your gut tested. Especially if you already feel like you have symptoms of gut dysbiosis, it’s important to start dealing with this before pregnancy! But even if you don’t have any digestive symptoms, you can still have dysbiosis, and it’s important to get tested before becoming pregnant. Check out the last section in my article for more information about testing.
  • Consume probiotics and prebiotic-rich foods regularly. Probiotics can influence the immune system in a way that weeds out “bad” bugs and makes more room for good bugs, while prebiotics can increase counts of good bacteria that colonize the gut. Doing both can help improve your overall balance of gut flora, some of which will then be passed onto the placenta to affect your baby’s development. Probiotic supplementation can also help regulate the unbalanced microflora composition observed in obesity and diabetes. (19)
  • Eat a diet with plenty of plant matter, high-quality meats, and fat. Eating lots of fruits and vegetables that contain polyphenols and fibers can help you get those prebiotics into your diet. Healthy fats include olive oil, avocado oil, pastured animal fats, and coconut oil.
  • Exercise. Recent studies suggest that exercise can increase the number of beneficial microbial species, enrich the microflora diversity, and improve the development of commensal bacteria. All of these effects are beneficial for preparing a healthy, balanced gut for your and your baby. (20, 21)

I discuss all of this (and more) in my 8-week digestive health program, Build Your Biome. If you’re thinking about starting (or expanding) your family soon, BYB is a great way to go through all the steps to take care of any gut bacteria imbalances before you become pregnant.

Or, if you want to just dive a bit deeper into all things gut-health, check out my free 60-minute training on digestive issues!

Click here to get access to that.

For those of you who are preparing to get pregnant or have had kids — did you consider your gut health? Tell me in the comments!

Does Gut Health Impact Mental Health?

When we think about our mental health, I’m sure most of us don’t think about our gut.

But did you know that your mental well-being may be influenced by the microscopic creatures living in your gut microbiome? The connection between gut health and mental health is one that has recently been gaining more attention, as scientists believe that the gut microbiome has enormous potential to yield new “psychobiotics.”

Psychobiotics are beneficial bacteria (probiotics) or support for such bacteria (prebiotics) that act on your bacteria-brain relationships. (1)

When I say “bacteria-brain relationships”, I’m referring to the “gut-brain axis,” an important concept that I’ve talked about before, but I’ll briefly outline it again below.

The gut-brain axis is comprised of two kinds of nervous systems: the central nervous system (CNS) and the enteric nervous system (ENS).


  • The CNS consists of the spinal cord and brain, and contains a crucial feature called the vagus nerve. The vagus nerve is the longest cranial nerve you have, running from near the hypothalamus all the way to your intestines where it reaches the other big player in the gut-brain axis, the enteric nervous system.


  • The ENS is connected to the CNS by the vagus nerve, and this system is embedded in the lining of the gastrointestinal system. The ENS is often called the “second brain” which explains why you can sometimes “feel” your emotions in your gut. Despite the fact that under normal circumstances the ENS is in conversation with the central nervous system, research shows that it is entirely capable of functioning all on its own, even when severed from the vagus nerve that connects it to our brain.


So altogether, we have something that looks something a bit like this:

Source: Alcock, J., Maley, C. C., & Aktipis, C. A. (2014).


The researchers who created this diagram used a very fitting analogy to think about our gut microbes, which I find helpful. They described our gut bacteria as “microscopic puppet masters” that can do an amazing number of things that change how our body works.  

Microbes can:

  1. Produce toxins in the absence of nutrients that can alter mood.
  2. Change how certain receptors (like taste) work.
  3. Manipulate our brain’s reward pathways.
  4. Hijack neurotransmitter communication between the gut and brain via the vagus nerve.

These effects are represented in the diagram by the hand-controllers that look like a cross, and our little microbes are the ones “running the show.” 

Although there are multiple ways that gut microbes can act on the gut-brain axis, the vagus nerve (depicted as the thin, gray lines with tendrils shooting off from the side of inside the torso) has been posited as one of the main pathways since it is the main neural axis between the gut and the brain. (3,4)

We still don’t know entirely know how this communication line works, but we do know that signals can move along the vagus nerve or be carried by chemical messengers (i.e. serotonin), and have the potential to alter brain function and activity.

A Healthy Gut Makes for a Healthy Brain


Brain health and gut health have a tremendous effect on one another. Twenty years ago, scientists noticed that our gut microbiota directly affects our central nervous system.

When they administered oral antibiotics to patients with hepatic encephalopathy (a condition of brain dysfunction from liver insufficiency), it was associated with a dramatic improvement. (5) So, targeting and changing the gut microbiome somehow led to a positive change in brain function.

Lately, there has been more research exploring whether our gut health is tied to neurological disorders such as Parkinson’s disease. (6,7) Unfortunately, it’s still somewhat of a “chicken-or-the-egg” dilemma. Is it

Is it having Parkinson’s that changes our gut? Or is it changes in the microbiome that can predict Parkinson’s? What we do know is that gastrointestinal symptoms (such as inflammation or constipation) can often be the first signs of Parkinson’s, which is a sign that our gut health may very well have a lot to do with our mental health. (8)

One working hypothesis is that, in response to microbial imbalance, certain intestinal microbes release neurotransmitters, or chemical messengers, that can travel down the vagus nerve and alter brain behavior. 

It’s important to know that the release of neurotransmitters from both the gut and brain must maintain a careful balance.

If the microbiome churns out too much norepinephrine–a stress hormone–it can ramp up our HPA-axis and result in a larger stress response in our bodies. (9) If the microbiome produces too much or too little serotonin, it could result in changes in sleep, behaviour, mood, and also in some conditions such as autism, since altered serotonin systems have been shown to be associated with these changes. (10,11,12)

Although more research is needed, it’s possible that therapies that regulate microbiome imbalance could help treat or even prevent diseases such as Parkinson’s or Alzheimer’s before neurologic function is compromised. These findings also further highlight the importance of a balanced microbiome for lifelong health.

Gut Microbiota Can Influence Anxiety and Depression


There is increasing data that supports the role of microbiota in influencing anxiety and depressive-like behaviors.

In fact, it has been posited that the gut-brain axis may be the “missing link” in depression. (13) Many researchers have used animal models to demonstrate this link: experimentally elevated stress response and depression in germ-free rats can be reversed by administering a single bacterium like Bifidobacterium infantis, a strain found predominantly in the neonatal intestinal tract. (14,15 16)

Clearly, there’s a connection between our gut and how we feel.

So, to dig deeper into this idea, a research team at McMaster University in Toronto discovered that if they colonized the intestines of one type of germ-free mice with bacteria taken from the intestines of another mouse type, the recipient animals would take on aspects of the donor’s personality. Naturally timid mice would become more exploratory, whereas more daring mice would become apprehensive and shy. Pretty cool, huh?

To take it a step further, they took fecal material (that’s right folks, poop) from depressed patients and nondepressed patients; when compared, they found that depressed patients had far less diverse and rich gut microbiota. But what they found next was even more startling. Using lab rats for some classic microbiome meddling, they first gave antibiotics to rats to erase all of their microbiota. Then, they gave these rats a depressed patient’s microbiota via fecal transplant.

The results? When the rats received the transplant from a depressed patient, they became depressed; their cortisol levels and other types of stress hormones increased. Meanwhile, the rats who received a fecal transplant from nondepressed people exhibited no change.

So what does that tell us? Our brain isn’t always culprit behind mental illness, as is commonly thought. It tells us that if there’s mental distress, there’s very likely digestive distress. It’s a two-way street, and both must be addressed.

Improve Your Digestive Health for Better Mental Health


The microbes in our gut have an enormous influence on our brain and behaviors. Luckily, there are some steps that you can take to improve your digestive health.

Here are my top tips to keep your gut bacteria healthy to improve your mental health:



  • Eat probiotics. Fermented foods typically contain Lactobacillius and Bifidobacteria which have both demonstrated potential benefits to mental health. (17,18)


  • Choose a diet packed with prebiotic foods. Prebiotics support the growth of beneficial microbes which help regulate and balance our microbiome. You can either get prebiotics from your diet by eating plenty of fruits and vegetables which contain polyphenols and fibers. In addition to this, you may want to consider supplementing with prebiotics. My two favorites are GOS and FOS, which can be found in Galactomune from Klaire Labs and FOS Powder from NOW Foods, respectively.


  • Eat high-quality fats. Studies of deceased patients with Alzheimer’s found significantly reduced amounts of fats in their cerebrospinal fluid compared with controls. (19, 20) People with low cholesterol are at much greater risk for neurological problems, including depression and dementia. (21)


  • Manage stress. There is evidence to show that stress (especially if experienced early in life) alters the gut microbiota negatively, and can throw our system off balance. (22) Incorporate mind-body activities like meditation, deep breathing, tai chi, yoga, and more to keep your HPA axis in tip-top shape. Remember, both mental and digestive health need to be functioning optimally for us to feel our best!


If you’re ready to learn more about gut health and how to build a robust microbiome, join my mailing list to get access to my 60-minute training on the reasons you might be suffering from digestive symptoms and what to do about it.

Click here to get access to the free training!

Clearly, our gut health is incredibly important when it comes to mental health. What do you think? Will you change any of your dietary or lifestyle habits to improve your digestive and mental health? Tell me about it in the comments!