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!


The Role of Gut Bacteria in Fertility and Estrogen Dominance

I’ve talked before about the importance of optimizing your gut health before getting pregnant in order to promote a healthy pregnancy for both you and your baby.

But what about getting pregnant in the first place… Can your gut bacteria play a role in your hormone balance and fertility?

The science suggests that it very well might!

To understand why let’s take a closer look at infertility and one of its common causes: estrogen imbalance.


When you hear the term “infertility,” you likely think of a person or a couple that cannot and will never be able to have children. In the medical world, however, infertility does not refer to a permanent state at all.

A diagnosis of infertility simply means that you have not been able to get pregnant after a year of normal, unprotected sex (1).

It’s actually a diagnosis that is far more common than you might realize. According to recent statistics, between 7% and 15.5% of American women experience infertility in any given year, and the majority of women (51.8%) meet the criteria for infertility at least once during their menstruating years (2).

While there are many reasons a couple might have difficulty getting pregnant, among the most common are hormone imbalances (3, 4). And abnormally high levels of one specific sex hormone is frequently implicated in infertility in both men and women: estrogen (5, 6, 7, 8).

Let’s look at each of these individually.


Most women need little reminder that our fertility depends on a highly-coordinated 28ish-day cycle in our hormone levels. Most of us also know that one of the key players in this hormonal dance is estrogen.

Estrogen has two very important jobs in the female menstrual cycle. First, it triggers a spike in the levels of a hormone called luteinizing hormone (LH) from the pituitary gland in the brain. This spike in LH levels is what triggers the ovary to release a mature egg into the fallopian tube, where it can be fertilized (9).

After a successful ovulation, though, estrogen works together with yet another hormone called progesterone to prevent a second ovulation from occurring. Estrogen and progesterone do this by acting on the pituitary gland in the brain to make sure no more LH is made until the following cycle (or, if pregnancy occurred, until after birth). At the beginning of the next cycle (menstruation), estrogen and progesterone levels dip down, signaling to the brain that it is safe to produce another spike of LH (9).  

Constant high levels of estrogen, without a significant dip signaling the start of a new cycle, can trick your brain into thinking you’ve already ovulated, and prevent you from ovulating again (9). This is actually the logic behind hormonal birth control (the pill).

As you might imagine, this can play a significant role in infertility.


While we often think of estrogen as a female hormone, men also have healthy baseline levels of estrogen that are required for sexual and reproductive functions.

At moderate levels, estrogen promotes (and is necessary for) a healthy libido and the production of sperm in men. At elevated levels, however, estrogen can have the opposite effects (6).

Too much estrogen in men decreases their libido. This is because, as in women, estrogen in men acts on the pituitary gland in the brain to decrease the production of LH. In men, this hormone stimulates the testes to produce testosterone. Without enough LH, there is a drop in testosterone, and low testosterone lowers male libido (6).

Elevated levels of estrogen also decrease the production of sperm by the testes. This is due to the estrogen-induced decrease in LH and testosterone levels, both of which directly stimulate the testes to produce mature sperm (6).


Clearly, a buildup of estrogen is not optimal for you, or your partner’s, fertility. But what’s any of this have to do with your gut bacteria?

A lot, believe it or not! There are multiple mechanisms which link your gut bacteria to your estrogen levels.


Your gut bacteria are actually an integral part of the normal regulation mechanisms your body uses to keep estrogen levels normal.   

See, every day your liver pulls estrogen out of your blood and binds it to a sugar-metabolite called glucuronic acid. This sugar-estrogen complex is then mixed with your bile, which is dumped into your digestive tract to help with digestion (10, 11, 12).

Now, this sugar-estrogen complex is bigger than estrogen by itself and it can’t be absorbed through the intestinal wall very well. Because of this, much of the estrogen gets stuck in the intestines and is eliminated from your body via bowel movements (10, 11, 12).

And this is where your gut bacteria come in. They have special enzymes that are able to cut estrogen free from the sugar, called β-glucuronidases. The freed estrogen molecule can then be easily absorbed and re-enter your bloodstream (10, 11, 12).

This is a natural part of the process and the liver binds more estrogen to bile acids than needed with the knowledge that some of it will be coming back, thanks to your gut bacteria.

This balance can be upset, however, if you have abnormal numbers, types or ratios of bacteria in your intestines (called dysbiosis) (13).

This is because some gut bacteria have β-glucuronidases that free estrogen better than others (14). With an unhealthy mix of gut bacteria, your microbiota can free too much estrogen, allowing much greater levels of estrogen to be reabsorbed back into your body than normal and pushing estrogen levels in your blood up (13).


In addition to the role the gut microbiota play in balancing the levels of estrogen you make yourself (called endogenous estrogen), they also regulate how much estrogen and estrogen metabolites you absorb from food sources (called exogenous estrogen).

Some gut microbes have enzymes that enable them to breakdown phytoestrogens (from plants) and polycyclic aromatic hydrocarbons (from barbequed or fried meats) into estrogens (15, 16). These estrogens can then be absorbed through the intestinal wall, raising your blood levels.

In fact, studies show that in men and postmenopausal women, the number one source of estrogen for their whole bodies is intestinal absorption from their food (17). And dysbiosis is associated with higher levels of estrogen in these populations, presumably at least partially through increasing the breakdown of dietary molecules such as phytoestrogens and polycyclic aromatic hydrocarbons (13).


In addition to the direct ways dysbiosis links your gut health to higher estrogen levels, there are also several indirect links.

For example, an abnormal balance of gut bacteria has been strongly linked to constipation (18, 19), inflammation (20) and obesity (21), all of which may be able to further drive up estrogen levels in your blood (8, 22, 23).


So, what does this mean for you if you are planning to get pregnant? What can you do to optimize your estrogen levels and boost your fertility?

Research shows that one of the most beneficial things you can do to optimize your estrogen levels is increase your fiber intake.

A high fiber diet is associated with improved microbial health and decreased risk of dysbiosis (24). In fact, increasing the amount of fiber in your diet for just 2 weeks is enough to significantly improve the composition of your gut bacteria (25).  

Additionally, fiber may be able to directly bind the estrogen-sugar complex in the digestive tract, helping eliminate it from the body. In a study examining estrogen (re)absorption in women, there was a direct and significant relationship between a woman’s fiber intake, the size of her stool, and the amount of estrogen she was able to flush from her body (26).

How you choose to increase your fiber intake is up to you, but boosting your fiber intake by increasing the amount of fiber-rich foods in your diet, rather than through adding fiber supplements, may give you more bang for your buck.

This is because the dietary source of fiber — plants — are also rich in polyphenols (27, 28, 29). As I outline here, polyphenols can help boost the health of your gut bacteria, so plant-based fiber-rich foods treat your dysbiosis to a one-two punch.

While fiber (and fiber-polyphenol-rich plants) is the most well established dietary tool to prevent dysbiosis and lower blood estrogen levels, other dietary and lifestyle changes may also be helpful. These include:

  • Exercising regularly (30)
  • Drinking enough water to stay properly hydrated, preventing constipation (31)
  • Taking a probiotic, which contains healthy gut bacteria that can help repopulate your gut with healthy microbes (32)
  • Avoiding broiled, fried and barbequed meats that are likely to contain high levels of polycyclic hydrocarbons (33)

However, if you have a lot of digestive symptoms like constipation, diarrhea, bloating, or gas, you may need help beyond these simple dietary and lifestyle changes.

This is because digestive symptoms can indicate that you have severe dysbiosis, or conditions like SIBO or parasites that need a more in-depth approach, including antimicrobials (or antibiotics) and other supplements.

That said, you can have imbalanced gut bacteria without any symptoms at all, so if you want to maximize your chances of getting pregnant or prevent estrogen dominance, it’s a good idea to test even if you don’t have digestive symptoms.

There are multiple tests to determine the health of your gut microbiota that can give you more precise information regarding your gut health. This can provide you with a roadmap to optimizing your digestive health and, in turn, your fertility.

If testing indicates you have dysbiosis, SIBO, or any other type of imbalanced gut flora, you’ll want to clear out that bad bacteria and balance your biome. If you need more help with that, check out my 8-week online program, Build Your Biome.

For women who have ever struggled with infertility, did you experience that taking care of your gut health through diet and lifestyle changes made a difference in your ability to get pregnant?

For women who are thinking about starting a family in the near future, do you think you will consider your gut health more now, before you start trying? Tell me 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!

Can Taking Prebiotics Heal Lactose Intolerance?

75% of the world’s population suffers from lactose intolerance, and if you’re one of that 75% you know how *ahem* uncomfortable the symptoms can be.

However, new research released in January of this year might have a solution for those dealing with this annoying condition: prebiotics.

If you don’t know already, I’m a huge fan of prebiotics (probiotics are great, too, but I think they get all the glory!).

Never heard of a prebiotic? Prebiotics feed probiotics. They are specific types of carbohydrates that selectively feed beneficial bacteria in the gut. Probiotics are the bacteria living in your gut, and prebiotics feed them to keep them alive and healthy.

The Study

In this study, researchers gave lactose intolerant individuals increasing dosages of GOS (galacto-oligosaccharides, a specific type of prebiotic) over the course of about a month as they avoided dairy in their diet. They began participants at 1.5g of GOS and worked their way up to 15g. Each dose was given once per day.

After a month of being on GOS, participants stopped taking it and started including dairy products in their diet for the next 30 days.

The Results

After a month of GOS supplementation, 71% of participants reported improvement in at least one symptom (pain, bloating, diarrhea, cramping, or flatulence) and after incorporating dairy back into their diet, 69% said that their symptoms were improved.

GOS supplementation and dairy introduction had a pretty significant impact on the microbiome of these participants. Researchers noted that 90% of those treated with GOS had what’s called a “bifidogenic” response, meaning that counts of Bifidobacterium were increased.

Now, not everyone will respond to GOS. “Nonresponders” simply don’t see a bifidogenic response, so their counts of Bifidobacterium don’t rise in response to GOS supplementation.

Interestingly, the folks who were nonresponders in this study did not see improvement in their lactose intolerance symptoms, while all participants that did have a bifidogenic response to GOS supplementation saw improvements in their symptoms. This was a pretty small study with just 30 participants, but the fact that the 3 participants who didn’t have a bifidogenic response also did not see any improvement in their symptoms is pretty telling — it likely means that at least part of the mechanism by which GOS supplementation works to improve lactose intolerance is by increasing counts of Bifidobacteria in the microbiome. Some of these types of bacteria are lactose-fermenting, so they can help you digest the lactose coming in through your diet.

Should You Try GOS Supplementation to Help with Lactose Intolerance?

This is, of course, just one small study, so we need to take it with a grain of salt. However, given that prebiotics have so many other benefits, I think adding GOS to your supplement regimen is a great idea in general, but especially if you’re looking to improve your lactose tolerance.

As for dosing, this study went up to 15g, which is pretty high. Other studies have shown that 5g has a bifidogenic effect, while minimizing other negative symptoms. My recommendation is to start with a small amount (in this study, they started at 1.5g) and work your way up to 5g. If you would like to go beyond that, keep an eye out for some negative symptoms that can go along with higher doses of prebiotics, like bloating. Whatever dose you decide on with your healthcare practitioner, I would give yourself a solid 30 days on the GOS supplement before attempting to add dairy products back in.

This study used a 95% pure GOS supplement, which, as far as I know doesn’t exist in commercial form. Jarrow used to offer a GOS syrup, but unfortunately it looks like it’s been discontinued. I’ve been using Galactomune with my clients which is a mix of GOS and beta-glucan. While I wish there was a straight GOS supplement on the market, I haven’t been able to find one (if you have, let me know in the comments!). That said, I’ve had great success with Galactomune, so I absolutely recommend it.

What do you think? Will you add GOS to your supplement regimen to help improve your lactose tolerance?


Join my newsletter to download my 5S Protocol to Optimize Digestion at Mealtime. In it, I’ll teach you how to stimulate the production of digestive enzymes and stomach acid, calm your system so it’s in “rest and digest” mode, and slow down to allow the proper breakdown and absorption of your nutrients.

Making sure you are optimizing your digestion is a great first step in improving your gut health!

Click here to download my 5S Protocol

How Do You Know If You Have Bad Gut Bacteria?

You’ve probably heard the words “microbiome”, “gut bacteria”, or “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 Unbalanced Gut Bacteria?

When you hear the terms “bad gut bacteria” or “unbalanced gut flora”, this can refer to a number of different conditions. The most common include small intestine bacterial overgrowth (SIBO), an imbalance of gut flora in the large intestine (commonly referred to as “dysbiosis”), 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 what is called 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).


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

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 Unbalanced Gut Flora

Okay, so now that you know what different types of unbalanced 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.


The most common symptom for SIBO is bloating. This is because when the overgrowing bacteria in the large 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 excessive flatulence or belching. 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.

Constipation is highly associated with methane-positive SIBO, while diarrhea is associated with hydrogen-positive SIBO. (3)

You can also exhibit no digestive symptoms 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.

Large Intestine Dysbiosis

The symptoms for dysbiosis of 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. I think imbalanced gut flora is 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.

Here’s just a sampling of the conditions/diseases associated with SIBO:

Conditions/Diseases associated with dysbiosis:

Specific pathogens/parasites and their associated symptoms/diseases:

Test, Test, Test!

Testing your gut for imbalanced bacteria is hugely important. I wish it was cheaper to do so (and hopefully we’ll see prices go down on these tests in the coming years) because I think everyone should do it!

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

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 a 3-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!

As for stool tests, I’ve recently begun using the GI-MAP test from Diagnostic Solutions Laboratory. It seems to be 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).

I still think other options for stool testing are good, like Doctor’s Data, Biohealth, and Genova, but personally, I’m using the GI-MAP now! These 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 them for you.

In my online program, Build Your Biome, you can order these tests (with a discount) and I’ll educate you on what everything means!

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.


Join my newsletter to download my 5S Protocol to Optimize Digestion at Mealtime. In it, I’ll teach you how to stimulate the production of digestive enzymes and stomach acid, calm your system so it’s in “rest and digest” mode, and slow down to allow the proper breakdown and absorption of your nutrients.

Making sure you are optimizing your digestion is a great first step in improving your gut health!

Click here to download my 5S Protocol

Can Your Gut Bacteria Help You Lose Weight?

Are you struggling to lose weight?

Perhaps you’ve tried restrictive diet after restrictive diet, exercise programs, and more – only to find that your weight doesn’t budge.

What if the answer to achieving and maintaining a healthy weight has been inside of you all along?

The Microbiome

Your digestive system is home to a vast ecosystem of trillions of bacteria that are diverse and complex. (1)

The different bacterial species all work together, much like a community, to ensure your digestive system and body functions appropriately. (2) The correct balance of microbiota can help your metabolism, increase your immunity, and can even enhance your brain functioning. (3)

Gut bacteria is acquired from birth, passed from mother to child (4), and there are many factors that could affect and alter your gut microbiota throughout your life, including:

  • The environment you live in. A large study investigated the differences in gut bacteria in rural and urban dwellers and found that urban people living in America had vastly different bacteria in their stool than those living in rural Malawi and Venezuela. They found that urban American fecal matter was the least diverse out of the groups, although this finding was only observed in adults and not in children. They also observed a difference in the clusters of bacteria found between the regions. (5) Another study showed that at least three species of bacteria differ in composition between people from different countries and continents. (6) These changes in bacteria could also be attributed to the differences in dietary habits between countries.
  • The food you eat. Carbohydrates, fat, and protein all have an effect on your microbiome. Protein-rich diets can encourage Bacteroidetes growth, while the Prevotella species is more dominant in the gut of those eating carbohydrate rich diets. (7). Your diet can have an impact on your gut bacteria in as little as 24 hours. (8)
  • The people you surround yourself with. The old saying that you become who you spend the most time with can also be true for gut microbiota and body weight. In mice studies, researchers found that when they housed obese mice together with lean mice and fed them both low-fat, low-sugar diets, the obese mice that lived together with the lean mice acquired lean bacteria faster than those who lived with other obese mice. (9
  • Your age. Even though a child’s gut bacteria can develop to adult-like maturity by the time they reach 3 years old, your gut bacteria changes as you age. The types of bacteria found in the microbiome are different in children and adults; in babies, more bacteria that make folate are present, whereas in adults the bacteria focuses more on metabolizing the folate from the diet. 

The Role of Gut Bacteria in Obesity

There’s been a lot of research done surrounding the idea that your gut bacteria alters your propensity for obesity and that gut bacteria change as a result of obesity or weight loss diets.

The increased interest in the role of gut bacteria on our metabolic health started when researchers microbiota from obese mice into mice with no gut bacteria and saw that when they did this, the mice with no bacteria gained fat mass, just like their obese counterparts.

Further research showed that when mice are fed a Western diet, they start to develop “obese microbiota.”

Obese microbiota can contribute to weight gain in the following ways: (10)

  • An increase the size of the villi in the small intestine (responsible for the absorption of nutrients) allows them to absorb almost double the energy of normal-sized villi
  • Gut motility slows down, allowing more time to digest food and absorb excess energy
  • Excess energy absorbed leads to increased fat in the liver and an increase in fat tissue throughout the body
  • Suppression of enzymes that break down fats lead to the increased conversion of triglycerides into fat cells

The idea that our microbiome plays a huge role in how we extract nutrients was confirmed in this study where they saw that when they gave germ-free mice a conventional microbiome, they produced 60% more body fat and developed insulin resistance, despite reduced food.

The Firmicutes/Bacteroidetes Debate

For many years, the main bacterial culprits for weight regulation have been thought to be the phyla Firmicutes and Bacteroidetes. If you’ve ever gotten a stool test done, you may have seen your Firmicutes and Bacteroidetes ratio listed. 

Much of the research available points to the fact that too many Firmicutes and too little Bacteroidetes can lead to weight gain. (10)

However, newer research has begun to challenge this mindset.

A study using data from the Human Microbiome Project and MetaHIT to investigate the relationship between gut bacteria and obesity found no difference in the Firmicutes:Bacteroidetes ratio between lean and obese participants. The researchers also found that bacterial diversity was not linked to obesity, which contrasts with the results of other studies. (11)

Another study looked at the gut bacteria in fecal matter from people from four different European countries and found that there was no link between BMI and the Firmicutes:Bacteroidetes ratio. The researchers did find evidence, however, to support the link between gut bacteria and its capacity to harvest energy, which is thought to promote weight gain. (12)

If you’d like to learn more about this topic, I recommend checking out this article.

The reality is that we don’t quite know if the Firmicutes:Bacteroidetes ratio really matters all that much when it comes to weight regulation. But the good news is that many of the interventions that seem to improve your ratio also seem to positively benefit your gut bacterial balance as a whole anyway.

Inflammation: the Underlying Factor Leading to Metabolic Dysfunction

While the research on whether the Firmicutes:Bacteroidetes ratio has much to do with weight regulation remains inconclusive, we do know that dysbiosis, in general, is a big problem when it comes to metabolic health.

This is because when we have unhealthy, unbalanced bacteria (dysbiosis), it leads to intestinal permeability and chronic, low-grade inflammation. This inflammation is highly associated with obesity and metabolic conditions like insulin resistance and diabetes.

If you have imbalanced gut bacteria, you develop localized inflammation within the gut, which contributes to intestinal permeability or “leaky gut”.

Leaky gut means that the cells that make up the gut barrier open up and allow larger particles into the bloodstream, like lipopolysaccharides (LPS). Once in the bloodstream, LPS causes chronic low-grade inflammation throughout the body.

This low-grade inflammation is associated with many diseases, but especially with metabolic disorders like obesity and diabetes.

Here is a list of the many different conditions LPS has been associated with:

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.

What Diet and Lifestyle Factors Increase LPS Concentrations?

Diet is probably the most studied contributor to LPS concentrations. When researchers do these diet studies, they’re typically comparing a high-fat, low-carb diet with low-fat, high-carb diet.

Pretty much across the board, it’s the high-fat diets that lead to a negative change in gut bacteria and higher LPS levels. (You can see one example here.)

Four weeks on a high-fat diet increased counts of LPS-containing bacteria and caused what researchers have deemed “metabolic endotoxemia” (essentially, high LPS concentrations causing chronic low-grade inflammation) in mice. This high-fat diet contained 72% fat (corn oil and lard), 28% protein, and <1% carbohydrate. When researchers used a 40% fat diet, they saw increases in LPS concentrations, but not as high as on a 72% fat diet. Metabolic endotoxemia caused increased fasting glucose levels, insulin levels, and levels of whole-body, liver, and adipose weight gain. (13)

Interestingly (though perhaps not so surprising to those who have been in the Paleo/Real Food world for a while), it is diets high in omega-6 fats that cause this reaction. Alternativately, diets high in fats like coconut oil or fish oil seem to be protective against high LPS levels. (14, 15)

How much you exercise also plays a role in your circulating LPS concentrations. High intensity exercise is associated with lower levels of LPS compared to being sedentary. (16)

If you’ve got a lot of stress in your life, you’re unfortunately promoting the growth of LPS-containing bacteria, which can lead to increased concentrations of LPS in your whole body. (17) (Want to learn more about how devastating stress can be for you digestive system? Read my article on the topic here.)

Though I hope most of you aren’t exposed to cigarette smoke on a regular basis, it also causes LPS-derived inflammation. (18)

A Healthy Gut Means A Normal Weight

OK, so you probably understand by now that high concentrations of LPS in the body seem to be responsible for many of the modern metabolic disorders we see today like obesity, insulin resistance, and diabetes. So how can you prevent getting high concentrations of LPS in your system and help yourself lose weight or prevent metabolic disease?

Here are my top tips:

  • Eat a varied diet with plenty of plant matter to get fiber, prebiotics, and polyphenols
    • Fiber and prebiotic intake have been shown to improve the cluster of symptoms seen in metabolic disorders and improve gut health. (19) Prebiotics also seem to ameliorate LPS-induced inflammation. (20)
    • Polyphenols reduce counts of LPS-containing bacteria and increase counts of beneficial bacteria as well as prevent metabolic endotoxemia and improve intestinal permeability. (21, 22) I’ve written an entire article about the benefits of polyphenols for gut health here.
  • Consume a moderate fat diet and reduce exposure to omega-6 fatty acids
    • I think a higher-fat diet is likely ok provided you have sufficient fiber and prebiotic intake, but to err on the side of caution, I’d recommend that most people consume a moderately-high fat diet (30-60% of calories). Within this amount, your fats should come from healthy options like omega-3s, coconut oil, olive oil, avocado oil, and pastured animal fats.
  • Consume probiotics regularly
    • Several studies have shown improvements in LPS concentrations, body weight, glucose metabolism, insulin and leptin sensitivity, among other benefits with probiotic treatment. (23, 24) Please note that probiotics’ effects are strain-specific, so we don’t know if all strains are equally as effective in this regard.
  • Exercise appropriately
    • As mentioned above, high intensity exercise seems to have a beneficial effect on LPS concentrations. In addition to this, exercise modulates the microbiome and gut health in a very beneficial way. (25)
  • Manage your stress levels
    • As I discussed previously, stress hormones seem to promote the growth of LPS-containing bacteria. Stress also causes intestinal permeability, meaning that LPS can then more easily get out of the gut and into other tissues, causing system-wide inflammation.


Join my newsletter to download my 5S Protocol to Optimize Digestion at Mealtime. In it, I’ll teach you how to stimulate the production of digestive enzymes and stomach acid, calm your system so it’s in “rest and digest” mode, and slow down to allow the proper breakdown and absorption of your nutrients.

Making sure you are optimizing your digestion is a great first step in improving your gut health!

Click here to download my 5S Protocol

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Sign up for the Fermented for 14 Challenge 2015!

Sign up for the Fermented for 14 Challenge 2015!

Are you ready to get your gut bugs in good shape?


Here’s the challenge: 1 serving (1/2 cup) of fermented foods every day for 14 days. 


Trust me, I know it can be hard to get in the habit of eating fermented foods. You might know that they’re great for you and that you should be eating them – but you just don’t do it. I think adding a fermented food a day is an easy change that could improve pretty much everyone’s health, but the fact is so many of us don’t do it on a regular basis (I’m guilty here, too!).

Our gut bacteria are the foundation of our health, and it’s our job to nourish them. From weight loss to eczema, fibromyalgia to chronic fatigue, fermented foods can help just about any health condition. It’s time to start eating them!  Join me in the Fermented for 14 Challenge to give those gut bugs some lovin’.

You can buy your fermented foods for the challenge or make your own (don’t worry, I’ve got recipes for you!). Or, buy some and make some – it all counts! What really matters is that your gut is getting fermented foods every day of the challenge.

When you sign up, you’ll get…

  • My Eat The Good Bugs eBook, complete with four easy fermented food recipes using simple ingredients from your local grocery store (lemon-ginger soda, pickles, yogurt, and kimchi – check out the picture above!) You’ll also get a list of my favorite brands you can buy at the store or online.
  • A weekly meal plan that includes 1 meal for each day of the challenge that incorporates one of the fermented foods from my eBook.
  • Daily emails with motivation, information about the microbiome, and more!
  • Access to the Fermented for 14 community on Facebook

Think you’re up for the challenge? Fill out the form below to register!

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P.S. Want to enter to win TONS of fermented foods? You can enter the giveaway below or check out the giveaway page here.
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Got Anxiety? Here’s How Your Gut Microbiome Plays a Part

Got Anxiety Here's How Your Gut Microbiome Plays a Part

Anxiety is the most prevalent mental illness affecting those living in the United States with about 40 million sufferers. (1) If you deal with this condition, you know that anxiety can be debilitating and affect your quality of life. But did you also know that the trillions of microbes living in your gut can play a part in your condition and potentially help you heal?

These microbes living in us are often referred to as the “forgotten organ” because they play such a large role in our well-being, but it is only recently that we’ve started to realize the impact this organ has on the body. (2) Unfortunately, the Western lifestyle takes a significant toll on the health of our microbiome with constant stress, unhealthy diets, lack of sleep, and more leading to a condition called dysbiosis.

Dysbiosis, the imbalance of gut bacteria, has been associated with a variety of mental disorders including anxiety. (3) While there aren’t many studies done on humans, we have seen mice exhibit increased anxious behavior when exposed to pathogenic bacteria in the gut. (4) It’s probably no surprise, then, that those with anxiety are also likely to suffer from a digestive disorder associated with imbalanced gut bacterial as well like Irritable Bowel Syndrome (IBS).

I recommend that you test your microbiome for dysbiosis and pathogens by using a functional medicine lab – your healthcare practitioner can then interpret this information for you and prescribe the correct treatment depending on what is going on in your gut. This is the #1 step anyone with anxiety should take! You don’t want unwanted pathogens hanging around wreaking havoc on your gut health (and in turn your mental health!). Directlabs.com offers a number of stool tests that you can order yourself – I have tests from both Metametrix and Doctor’s Data (two of my favorites) listed in my portal here.

When humans are given specific strains of probiotics, their anxiety improves as does their HPA axis function. (5) The strains of probiotics used in this study (Bifidobacterium longum R0175 and Lactobacillus helveticus R0052) can be found in two products in the United States: Pure Encapsulations’ ProbioMood (which you can purchase in my supplement dispensary) and Xymogen’s Probio Defense.

Prebiotics, which feed healthy gut bacteria, are also useful for anxiety. Stress-related disorders seem to respond to the prebiotic GOS (galactooligosaccharide) in particular, which help the HPA axis to function appropriately in addition to making us pay more attention to positive stimuli vs negative stimuli. (6) My go-to GOS prebiotic is Galactomune from Klaire Labs, which you can purchase in my dispensary.

Eating a healthy, ancestral diet is also associated with lower anxiety scores, while Westernized diets are associated with the opposite effect. (7) This is thought to be due to many factors including inflammation, but also to the effects of these diets on the microbiome. Another reason to keep up your healthy Paleo diet!

The microbiome and the brain operate on a bi-directional axis, meaning that the gut affects the brain and vice versa. Because of this, anxiety and gut problems can be a vicious cycle where anxiety  makes you more likely to develop dysbiosis (the imbalance of gut bacteria) and dysbiosis makes you more likely to suffer from anxiety. But dealing with both conditions simultaneously (i.e. treating dysbiosis and reducing stress to the degree you can) can help alleviate both problems. To learn more about stress and its impact on the gut, check out my article on the topic here.

While anxiety can be a difficult diagnosis to deal with, there is more and more research coming out every day about the relationship between anxiety and the microbiome. If you suffer from anxiety, your treatment plan should definitely address any problems in the gut!

To recap, those with anxiety should focus on:

  • Reducing stress as much as possible by incorporating mind-body activities like meditation, yoga, etc
  • Testing and treating for dysbiosis with a trusted practitioner (I can help!)
  • Adding probiotics to their routine, in particular the Bifidobacterium longum R0175 and Lactobacillus helveticus R0052 strains  which can be found in the probiotic supplements ProbioMood and Probio Defense.
  • Adding prebiotics, especially GOS, which has shown to have a positive impact on the HPA axis and anxiety. Try Galactomune to get more GOS in your diet.
  • Eating a healthy, ancestral diet consisting of fruits, vegetables, meats, nuts, etc. (e.g. a Paleo diet!)

Now I want to hear from you: what have you done to combat your anxiety? Are you focusing on the gut?


Does Stress Cause Digestive Problems?

Does Stress Cause Digestive Problems?

Most of us can probably guess that stress affects the body negatively – but how does it affect the gut?

The Gut-Brain Axis

Changes in our mental state, like feeling scared or nervous, can lead to problems in the gut. Ever had to do a big presentation or take an important test and experienced heartburn or diarrhea as a result? That’s the brain and the gut in communication. This goes the other way too. Changes in our gut microbiota and changes in our intestinal permeability can affect our mental state, causing depression and anxiety. (1) These bidirectional signals going from the gut to the brain and vice versa can either keep us healthy or they can cause a great deal of discomfort.

It is vital to deal with any significant health issues that affect either the brain or the gut, but it’s important to note that neither will truly heal if you don’t also focus on the other. If you have a parasite and you treat it without dealing with your chronic stress, you leave yourself open to reinfection or sometimes, your body simply won’t be able to get rid of the parasite because of the chronic stress.

Chronic stress leads to negative changes in the gut, while relaxation promotes gut health. On the flip side, poor gut health exaggerates our stress level, while improvement in gut health lowers stress.

The fact that the gut-brain axis is a two-way street is especially important to remember. No matter how hard you try to boost the well-being of your digestive system, you’ll never fully feel better without dealing with stress; it will put you right back where you started if you don’t address it. Chronic stress is a risk factor for digestive disease, and those with digestive conditions are also likely to suffer from mood disorders. (2,3) In a country where over 40 million people suffer from psychiatric illness and 70 million are diagnosed with a digestive disorder, addressing the gut-brain connection is essential. (34)

Before we jump into the wild world of neurogastroenterology (that’s a fun one!) and learn how stress affects our gut, let’s get better acquainted with the nervous systems that make up the gut-brain axis: the central nervous system and the enteric nervous system.

The Central Nervous System (CNS)

The central nervous system consists of the spinal cord and the brain. It sends and receives signals to and from the peripheral nervous system and governs nearly everything we do with our body. Given the crucial role it plays, it is commonly referred to as the “control center” of the body. The CNS communicates with our gut via the vagus nerve, the longest cranial nerve we have, running from near the hypothalamus all the way to our intestines where it reaches the other big player in the gut-brain axis, the enteric nervous system.

The Enteric Nervous System (ENS)

The enteric nervous system is considered to be a part of the autonomic nervous system which is housed under the peripheral nervous system. The ENS is often called the “second brain” which explains why we can sometimes “feel” our emotions in our gut. This “second brain” has many similarities to our true brain – it contains over 100 million neurons (more than the spine, though less than the brain) and produces many of the same neurotransmitters found in the brain such as serotonin, dopamine, and acetylcholine. (5) 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. (6) No other organ can claim this impressive feat – all require signals from the brain to function. Neat, huh?

Consider this other incredible fact: about 95% of our serotonin (the “feel good” chemical) is found in the gut, not the brain. (7) Normally associated with its anti-depressive properties, this chemical serves many different purposes and is mostly found in the enterochromaffin cells in the gut. Serotonin is released by these cells when food finds its way into the GI tract, signaling contractions to move the food down the intestinal tract. It’s also responsible for the stomach upset we experience when we eat spoiled food – serotonin is released in high amounts when the gut comes into contact with an irritating food and triggers both diarrhea and vomiting to expel the dangerous food.

Stress: The “Fight or Flight” Reaction

Two other relevant nervous systems to consider are the parasympathetic and sympathetic nervous systems. In times of great stress our sympathetic nervous system is activated, causing the universal experience of a racing heart and rapid breathing. You may have heard of it referred to as the “fight or flight” reaction, owing to the two courses of action our bodies are preparing us to take in these stressful situations. The parasympathetic nervous system, on the other hand, is often called our “rest and digest” system because when we are in a relaxed state the body focuses on exactly those activities.

In today’s world, we spend far too much time in the “fight or flight” mode and not nearly enough time “resting and digesting”. We’re constantly activating our “fight or flight” response with the many stressors we experience on a daily basis like traffic, a big project at work, financial issues, etc.

This is very different from how our hunter-gatherer ancestors experienced stress. While they may have been chased by predators on occasion, much of their time was spent in the “rest and digest” mode. Their ratio of “fight or flight” time to “rest and digest” time was the exact opposite of ours – and they had better digestive (and overall) health because of it.

I’m going to briefly go over what happens when we come into contact with a stressor so that you can understand the rest of this article, but if you want a more in-depth review, you’ll want to check out our free eBook, Overcoming Adrenal Fatigue, which you’ll receive when you sign up for our newsletter.

The hypothalamic-pituitary-adrenal (HPA) axis is the stress “control center” and begins the activation of the sympathetic nervous system by coordinating the many moving parts in a stressful situation. Upon recognizing a stressor, the HPA axis is stimulated and corticotropin-releasing hormone (CRH) is released from the hypothalamus. CRH travels within the blood to the anterior pituitary gland where it stimulates the production of adrenocorticotropic hormone (ACTH). ACTH then travels to the adrenal cortex where it ultimately stimulates the release of cortisol. You may have heard of cortisol as the body’s main “stress hormone”. During times of crisis, as in our bear attack, cortisol works to keep blood sugar elevated so we can meet the glucose demands of the brain and helps the body retain sodium to keep blood pressure up. It also moves blood away from the digestive tract and instead toward the muscles and brain. This process is vital to keep us alive during a true “fight of flight” situation as it helps us do exactly that – fight or run away.

Our ancestors led lives that allowed them to have a balanced stress level. Despite running from the occasional predator, as long as they survived the attack they would then have plenty of time to rest, calm down, and turn the stress reaction off afterwards. This enabled them to produce the right amount of cortisol – not too much, which has been associated with gaining abdominal fat and developing chronic disease, and not too little, which is correlated with exhaustion.

Unfortunately, most of us don’t live like our ancestors did. Instead, we experience chronic minor stressors all day long for our entire lives. Sadly, the HPA axis can’t differentiate much between major stressors like being attacked by a bear and minor ones like being reprimanded by our boss for being late to work. It’s stimulated just the same either way, going through the same motions and putting us into “fight or flight” mode in either situation.

In the next few sections, we’ll review how chronic stress leads to gut issues by altering intestinal permeability, increasing inflammation and lowering immunity, changing the gut microbiota, and finally, actually increasing the amount of pain we feel.

Stress Opens the Intestinal Gates

We want to prevent our gut lining from becoming permeable – you’ve probably heard about the negative effects of “leaky gut” already. Consider the placement of the gut; from mouth to anus it’s not technically “in” our body, it’s outside. If you think of the body as a donut, the gastrointestinal tract is the donut hole, outside the rest of the donut. Pretty amazing to think that our entire digestive system is technically not even “inside” us.

When we think of the GI tract like this, we realize that it’s exposed to a lot on a daily basis. The gut barrier comes into contact with many different substances, from possibly harmful bacteria to food particles that need to be digested before being allowed into the body. It’s crucial that this barrier functions appropriately to keep the things we don’t want out and only allow the things we need in. When working normally, the gut lining acts as a sieve, only allowing particles that fit through to get to the other side. When the sieve breaks, things that aren’t supposed to get across now flow through freely. When the gut barrier leaks, we’ve got a big problem.

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. (8) 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. (9) Yes, several days. When’s the last time you went several days without any stress whatsoever?

This research has also shown that mast cells play a large part in the increased intestinal permeability that occurs as a result of stress. You may have heard of mast cells as the cells involved in allergic responses, as they are responsible for releasing histamine when they become unstable or “degranulate”, causing the typical allergic response – runny nose, watery eyes, congestion, etc. What you might not know about mast cells is that they’re also found along the gut’s mucosal wall and they contain CRH receptors. Remember, CRH is released at the start of the “fight or flight” reaction. Since mast cells have CRH receptors it means that they are responsive to the amount of CRH flowing through the body. When CRH attaches to mast cells, they degranulate and release their many chemicals, including histamine.

Researchers studying rats under water aversion stress found that rats bred to have no mast cells in their intestines didn’t show increased intestinal permeability under stress, unlike their normal mast-cell containing counterparts. (8) This tells us that mast cells play a very important role in the integrity of the gut lining when it comes to stress, and that unstable and degranulated mast cells lead to intestinal permeability. By stabilizing these cells, we can help prevent the breach in our gut barrier.

These rat studies give us a glimpse into what’s going on in our gut while under chronic psychological stress, and it’s not good. Hardly any of us can go a few days without being stressed about something, which never gives our gut barrier time to heal after it’s become permeable thanks to the unstabilized mast cells. Because of this, we’re leaving ourselves open to harmful substances not meant to enter our bodies.

Stress Fuels Inflammation

Glucocorticoids are steroid hormones made by the adrenals in times of stress. We’ve already discussed the most important one in the human body: cortisol. Cortisol plays a significant role in turning off inflammatory reactions. In fact, if you suffer from an inflammatory bowel condition, you may have been prescribed a steroid like prednisone to reduce the inflammation in your gut. When prednisone enters the body it is converted by the liver to prenisolone, a derivative of cortisol, to exert its anti-inflammatory effects.

Let’s say we were running away from the bear chasing us, but we got caught. The bear bit us, but allowed us to survive. The body’s reaction to physical trauma – being bitten – is to rush blood to the wound, which swells the area, turns it red, and makes it hurt a lot. These are all signs of inflammation, which is the body healing itself. Once inflammation’s job is done, the inflammatory reaction is shut off and cortisol helps this happen. Short-term inflammation like this is a completely normal response and under usual circumstances it helps us. It’s chronic inflammation that gets us in trouble.

One of the recent theories suggests that we can develop chronic inflammation – in the gut and elsewhere – when we’re under prolonged stress. (10) This is thought to occur because chronic stress alters the way our cells respond to cortisol. In effect, when cortisol is high for a significant period of time, our body simply becomes less sensitive to its anti-inflammatory effects. When we are under stress for even longer and consistently activating the HPA axis, the axis can eventually become overwhelmed and stop producing the hormones that it’s supposed to (like cortisol).

Think about it like the story of the boy who cried wolf. When the body constantly cries out for help with these little stressors and activates the HPA axis over and over again, eventually the HPA axis doesn’t bother answering the cries anymore – or at least not with as much vigor as it did before. As a result, we produce less cortisol than we’re supposed to. Low cortisol levels also lead to chronic inflammation because we don’t have the ability to fight off bacteria and other unwanted substances that make it through the now permeable gut barrier.

It’s important to remember that we want just enough cortisol: too much, and our tissues become less sensitive to its anti-inflammatory effects; not enough, and we’re open to attack from bacteria and other particles crossing the gut barrier, causing inflammation; just enough, and we’re able to keep inflammation down and respond to stress appropriately.

Are you starting to see the chain reaction developing here? The stress response turns on, our gut gets leaky, cortisol levels soar, and then eventually fall, causing inflammation either way. What’s next?

Stress Lowers Immunity

Did you know that the majority of our immune system is actually housed in the gut? Our gut-associated lymphoid tissue (GALT for short) makes up almost 70% of our immune system by weight. You might be able to imagine why the gut would need to have such a strong immune system – it’s in constant contact with things from the outside world such as food particles, bacteria, and all the other things we inadvertently swallow. That’s a lot to deal with!

As part of the gut’s immune system, our gastrointestinal system secretes something called secretory IgA (sIgA), which is our first line of defense when it comes to all the substances our gut is in contact with. This important antibody is also produced in other parts of the body that are exposed to the outside world – it’s found in saliva, tears, and lung secretions. Chronic stress reduces our production of sIgA and by doing so, leaves us open to colonization by pathogenic bacteria in the gut.

Studies show that students under academic stress have lower levels of sIgA than those under less stress. (11) Up to two weeks after exam stress has dissipated, students still show lower levels of sIgA with no indication of recovery. Relaxation exercises, on the other hand, actively increase sIgA production. (12) Low sIgA leaves us susceptible not only to infections of the gut but also to infections in the rest of the body. With infections come even more inflammation, thus fueling the inflammatory fire already going when we’re under chronic stress. Low sIgA also gives bad bacteria the chance to take charge, changing our gut microbiota.

Stress Unbalances Gut Bacteria

The gut microbiota is absolutely vital to our digestive health (not to mention the health of our whole body!), but stress changes its composition in our gut, shifting it in a less favorable manner. Under chronic psychosocial stress, mice develop a condition called dysbiosis, the relative overabundance of bad bacteria coupled with low amounts of good bacteria in the gut. (13) This imbalance is associated with digestive problems like IBS and Crohn’s disease, and even conditions like fatty liver disease and acne. Not only does stress alter the balance of our bacteria, but it also reduces our gut’s microbial diversity (how many different types of gut bacteria we have). Interestingly, the less diverse our gut bacteria, the more likely we are to be overweight and have allergic diseases.

Using germ-free mice, researchers have been able to prove that the intestinal microbiota also play a vital role in the development of the HPA axis (remember that’s our stress control center). Germ-free mice are often used in studies because they allow us to monitor what happens when the body exists without gut bacteria, providing us the opportunity to see exactly how the microbiota affects physiology. When these adult mice are exposed to stress, they produce higher levels of ACTH and cortisol than mice with normal gut microbiota. (14) To further elucidate this relationship, researchers then colonized the gut of the germ-free mice with bacteria from the normal mice which partially reversed the exaggerated stress response. The effect was fully reversed when the mice were colonized with a specific strain of probiotics (good bacteria).

It is clear that stress alters our gut microbiota, and that the opposite is true too – our gut bacteria affect how we respond to stress. When our microbiota is negatively altered as a result of stress, it then sends signals back to the brain which manifest as even further stress. But wait, there’s more!

Stress Increases Pain

Did you know that most patients with IBS and other gut disorders often show enhanced perception of pain? (The fun science term for that one is visceral hypersensitivity.) While the normal response to stress is to increase the pain threshold, patients with digestive diseases unfortunately experience the exact opposite. Think about it like this: if you were being chased by a bear and you stepped on a sharp twig, you’d probably continue running and barely even notice that you’re hurt. That’s an exaggerated example of the normal pain experience in response to stress – we can handle more of it.

However, in studies looking at the pain response to gastric distention (gas or air in the gut causing bloating), those with gut disorders have a lower pain threshold – meaning they experience more pain – than those without digestive problems. (15) Research further shows that patients with gut conditions exhibit even more digestive symptoms like gas and pain when they’re under mental stress and feeling anxious. These symptoms decrease during periods of relaxation, further proof of the tight link between the brain and the gut. Here’s the unfortunate fact: if you’re someone with a digestive disorder, stress literally makes your stomach hurt.

Let’s go back to how the stress response starts for a moment: CRH is released from the hypothalamus, which begins the cascade of hormones eventually resulting in the production of cortisol. In rats, CRH administration causes mast cell degranulation in the colon. Remember the mast cells? These are the cells that, when not present in the intestines of rats, resulted in the rats no longer developing intestinal permeability as a result of stress. Research has shown that when those with IBS are given a mast cell stabilizer they are less sensitive to pain. (16) This tells us that having stabilized mast cells is vital to having an intact gut barrier and having appropriate pain sensation. It’s theorized that stress management techniques such as yoga can inhibit mast cell activation, thus having a positive effect on all types of conditions where mast cell activation is problematic. (17)

This brings us to the end of the stress train-wreck. When we’re stressed, our gut becomes permeable and inflamed, our immune system is compromised, and we’re subject to an altered balance of the bacteria living in our gut. As if this weren’t enough, being stressed out makes us feel worse by increasing the amount of pain we experience!

Overcoming A Stressful Life

I don’t want all of this to overwhelm you or make you feel like you’re destroying your gut health by being stressed out. I wanted to take you through this so that you can recognize the many negative effects chronic stress can have on the digestive system. So what should you do if you’re always stressed out?

Laura and I have outlined some specific steps to take in our free eBook, Overcoming Adrenal Fatigue that you can get by signing up for our newsletter. You’ll learn exactly what you need to do to help your body overcome the effects of chronic stress.

Now I want to hear from you: Did any of these effects surprise you? What do you plan to do differently now that you know how stress can affect your digestive system?