Research has consistently shown that a healthy and diverse microbiome is important for good health.

Our gut microbiome consists of different microbial species—such as bacteria, yeast, fungi and archaea—that populate the lining of our intestinal tract. Some are commensal (helpful), some are symbiotic (living in peaceful coexistence), and others may be harmful (pathogenic).

Our microbiome develops and changes throughout our life. A newborn’s microbiome is initially influenced by whether they were born by vaginal birth or c-section and by whether or not they were breastfed. As babies start to eat foods, their microbiome changes and diversifies. Over the course of our life several factors will influence our microbiome, such as our diet, lifestyle, stress, travel, antibiotic and drug use, and more.


While the words pre-, pro- and postbiotic may sound similar, they each play a unique and important role in both your gut and overall health. In this post, I answer the following questions:

  • what are pre-, pro- and postbiotics?
  • how do you get more of them from your diet?
  • how do they influence your health?


The International Scientific Association of Probiotics and Prebiotics (ISAPP) defines dietary prebiotics as “a selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit upon host health.”

In short, prebiotics provide food for the bacteria in our intestine and encourage their proliferation. Prebiotics occur naturally in many plant-based and polyphenol-rich foods such as fruits, vegetables, and whole grains. Bananas, asparagus, onions, leeks, garlic, Jerusalem artichokes, chickpeas, lentils, barley and oats are examples of prebiotic foods.

Certain non-digestible fibers, such as inulin (often from chicory root) and certain oligosaccharides (FOS, GOS, HMO), are examples of the fibers that bacteria thrive on. These types of fibers are often sold as prebiotic supplements. Sometimes prebiotics are added into probiotic supplements. Some manufacturers will use the word “synbiotic” to describe a supplement that contains both prebiotics and probiotics.

Consuming prebiotics can help increase the quantity and diversity of the organisms in our microbiome. However, prebiotics can feed both the good and bad microbes.

For individuals with certain gut conditions, such as IBS & SIBO, certain food and supplemental prebiotics may exacerbate their symptoms. Working with a knowledgeable practitioner to choose the right prebiotic—at the optimal treatment time—is very much advised.


The Food & Agriculture Organization and the World Health Organization define a probiotic as “live microorganisms which when administered in adequate amounts confer a health benefit on the host.”

The word probiotic actually comes from the words “pro” meaning “promoting” and “biotic” meaning “life”.

Probiotics are live microbes that populate our gut and provide us with health benefits. Consuming probiotics may help increase the number and diversity of the bacteria in our gut, reduce the growth of pathogenic microbes, aid digestion, and support our immune system.

Fermented foods, including yogurt, kefir, miso, and sauerkraut contain live probiotic bacteria. I always suggest that people start with small amounts of these foods to see how their body responds. More is not necessarily better and these foods do not work for everybody.

The market is flooded these days with a plethora of probiotic supplements! In our experience, the quality of these products can vary greatly. Additionally, some people do better with single strain probiotics, others do well with multi-strain products, while others respond more favorably to yeast-based (as opposed to bacterial) forms.


Postbiotics are the bioactive compounds that are formed after (aka “post”) the probiotic bacteria consume prebiotics. While these compounds are considered “waste products,” they offer various health benefits. In fact, many of the benefits we derive from prebiotics and probiotics are actually attributed to these postbiotics.

The International Scientific Association of Probiotics and Prebiotics (ISAPP) defines a postbiotic as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host.” 

Some examples of postbiotics include short chain fatty acids, enzymes, vitamins (such as vitamin B and K), amino acids, and antimicrobial peptides.

By eating more prebiotic and probiotic foods you increase the number of postbiotics in your body since postbiotics are their end product. Some foods, such as butter or ghee, contain short-chain fatty acids such as butyrate.

And, while less popular than prebiotic and probiotic supplements, certain postbiotics are available in supplement form.


When I think about the microbiome, the wise words of Goldilocks come to mind: Not too little. Not too much. Just right.

Our microbiome is constantly shifting and evolving. It is not only about balance, but about our unique microbial balance.

When we are in microbial harmony (which can be easier said than done for many!), we experience better health: improved digestion, a healthy intestinal barrier, robust immunity, protection from pathogens, optimal weight, and a decreased risk for allergies, food sensitivities and various mental and physical health conditions including cancer, diabetes and heart disease.


Original post dated May 2022. Most recently updated March 2024.

About Debbie Steinbock, HHC

After years of being told that she had an "incurable" chronic health condition, Debbie turned to her diet to help her understand her disease, restore her body, and regain control of her health. Her personal journey has given her the knowledge and compassion necessary to help her clients take an active role in their own healing. Since starting her practice in 2000, Debbie has successfully helped hundreds of people across the country to improve their diet, enhance their current state of health, and eliminate a variety of health conditions.

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