Prebiotics: Everything You Need to Know for A Healthier Microbiome


You hear a lot about probiotics these days, but what about prebiotics? What’s the difference between prebiotics and probiotics and should you be consuming both? In this article, we’ll cover everything you need to know about prebiotics.

What Are Prebiotics?

Prebiotics were first defined in 1995 as “non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria already resident in the colon.” (1)

That definition has been tweaked throughout the years and the latest update to the definition (decided on by the International Scientific Association for Probiotics and Prebiotics (ISAPP)) is as follows: a prebiotic is “a substrate that is selectively utilized by host microorganisms conferring a health benefit.” (2)

But let’s put this in plain English, shall we?

A prebiotic “feeds” your healthy bacteria and, as a result, benefits you and your body. Prebiotics can be found in both foods (typically high-fiber foods) and supplements.

While “classic” prebiotics such as fructooligosaccharides and galactooligosaccharides still fit this new definition, this expanded criteria now also allows some non-carbohydrate nutrition components such as polyphenols (a type of antioxidant) to be classified as prebiotics.

Why I Don’t Take a Diet-First Approach to Healing Gut Issues

You might assume that, as a dietitian who works with those with digestive problems and gut microbiome imbalances like SIBO and dysbiosis, I spend the majority of my time counseling my clients on diets like the low-FODMAP diet, SCD diet, GAPS, or any other number of restrictive dieting approaches out there.

Want the truth?

I spend the majority of my time talking to my clients about things other than the types of foods they’re eating. We talk antimicrobial herbs, stress reduction, sleep, exercise, calorie intake…but specific food choices? We don’t spend much time on those beyond general healthy eating concepts.

In my 7 years of working with digestive health clients, I’ve found that taking a diet-first approach to fixing microbial imbalance in the gut is the wrong move.

Here’s why.

Restrictive Diets Don’t Address the Real Problem

If you have gut issues like SIBO or dysbiosis, heavily restricting your diet doesn’t solve the problem. I’ve written about this concept specifically in regards to a low-FODMAP diet before, but it applies to practically every other restrictive dietary approach out there. The only exception to the “rule” would be the elemental diet (which I don’t even consider to be a “diet” per se;

Probiotics: An In-Depth Guide & The Best Probiotic Supplements on the Market


Probiotics have thundered onto the health and wellness stage — you hear about them everywhere now.  With claims running the gamut from “probiotics heal your gut” to “probiotics prevent cancer,” it seems as though they are just about a cure for everything.

But, do they actually do what they claim to? Or are these claims just another way to convince you to buy expensive supplements?

In this article I’m going to answer all of your pressing questions about probiotics. From the very basics of what probiotics are, through the details of probiotic strains, to the ways probiotics work at the molecular level; everything you need to know about this burgeoning field, you’ll find right here.

What are Probiotics?

Alright, first thing’s first. What are probiotics, exactly?

According to the Food and Agriculture Organization of the United Nations and the International Scientific Association for Prebiotics and Probiotics, probiotics are defined as: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” (1)

…And what, exactly, does that mean?

Well, basically, it means a probiotic is any species of bacteria,

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

leaky gut syndrome

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

Please note: there are affiliate links throughout this post. If you buy products through those links you help to support more great content like this!

What is Leaky Gut Syndrome?

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

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

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

Why Probiotic “Strains” Are Important & The Best Probiotic Strains on the Market

best probiotic strain

Did you know that the strain of a probiotic determines its effect? And that most probiotic supplements don’t tell you what strain they contain? In order to take the best probiotic for you, you need to understand which strain will give you the benefits you’re looking for.

What is a Probiotic?

No doubt you’ve heard all the hype about probiotics.

“Probiotics will heal your gut!”

“Probiotics will prevent food sensitivities!”

“Probiotics treat IBS!”

…among others.

There’s a million claims out there and a million more probiotic supplements to buy. So how do you know what the best probiotic supplement is?

Before we jump into that, let’s quickly define probiotics:

Probiotics, at their most basic definition, are “live microorganisms which when consumed in adequate amounts as part of food confer a health benefit on the host” (according to the World Health Organization).

What is a Probiotic Strain?

Probiotic strains are where things get a bit more complicated.

You see, most of us are used to seeing probiotic names listed on labels with two parts to the name.

How Do You Know If You Have Bad Gut Bacteria?

bad gut bacteria

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

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

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

Let me walk you through it!

What is the Microbiome

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

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

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

Normal Flora

Normal flora are exactly what they sound like —

What Probiotics to Take While You’re On Antibiotics

What Probiotics to Take While You're On Antibiotics

In this article, you’ll learn how probiotics can prevent some of the negative side effects of antibiotics and keep your gut healthy. You’ll discover the best probiotic supplements on the market for antibiotic-associated diarrhea and other digestive problems, as well as what probiotic foods to eat. 

What are Antibiotics?
What are Antibiotics Used For?

Antibiotics are a class of drugs that kill bacteria. They are used for harmful infections in or on the body. Common antibiotics include clindamycin and amoxicillin, though there are many different types of antibiotics on the market.

How Do Antibiotics Work?

Antibiotics work by either directly killing bacteria or preventing them from replicating or reproducing, thus dwindling bacteria numbers over time.

Antibiotic drugs only kill off bacterial infections in the body, which means that they aren’t useful for illnesses like the common cold or the flu, for example, because these are viral illnesses.

Side Effects of Antibiotics

Unfortunately, antibiotics are associated with a few side effects. These include:

  • Digestive problems
  • Clostridium difficile infection
  • Altering the Microbiome
  • Antibiotic Resistance

Digestive Problems

The most common side effects of antibiotics are digestive problems.

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

ibd ulcerative colitis crohns

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

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

Crohn’s Disease

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

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

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

Does Imbalanced Gut Bacteria Influence Psoriasis?

psoriasis microbiome gut bacteria

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

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

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

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

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

Current Psoriasis Treatments

Thankfully, there are many treatment options available to help people manage the many symptoms of psoriasis.

Is a High-Fat Diet Bad for Your Microbiome?

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

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

Factors That Lead to a Healthy Microbiome

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

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

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

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

And these changes in microbial balance can happen quickly —