Pre, Pro and Post-Biotics, What Are They and Why You Should be Taking Them

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Your health is so important and putting the effort into maintain it regularly is important, which is why I am a huge proponent of preventive medicine. If you take care of yourself now (exercising and eating healthy…. most of the time), you will have a better outcome moving forward compared to if you did not.

Recently it seems that I have been bombarded with new articles about gut health and its role in everything from chronic inflammation and obesity, to brain health and dementia (1).  If this is true, then it seems that the health of the bacteria that live in our gut is just as important as the health of our own cells. Unfortunately, that does not bode well for the majority of Americans who have a diet that is far from healthy. 

The bacteria that live in your gut, also known as your microbiome, can contain up to 1000 different species of bacteria, though it mainly consists of 30-40 different bacteria types (2,3). Collectively it can weigh as much as our brain and is nearly just as intricate too…. Crazy, I know. To summarize the microbiome is vastly unique and plays a very important role in our general health, so keeping it happy is important.  

I know you have probably heard or seen a lot about the increase in gut health products on the market, as well as the terms prebiotics, probiotics and probably the lesser known one post biotics. We will discuss all three here, what they are, what they can do, and why you should care about them and even consider using them.


First let’s start by talking about prebiotics. Prebiotics are essentially the food for your microbiome (aka the bacteria that live in your gut). Prebiotics are usually non-digestible fibers, which means your body can’t break them down to use for energy. This makes it easy for prebiotics to reach their destination (your gut), feed your intestinal friends and provide amazing benefit without having to worry about any breakdown along the way. You will learn later on how this is not the case for probiotics..

Vegetables and grains on wood table

Prebiotics are present in fiber rich foods such as fruit (bananas, apples), vegetables (garlic, onions, asparagus) and whole grains (barley, oats, flaxseeds, wheat bran). The International Scientific Association for Probiotics and Prebiotics (ISAPP), even has a strict definition of what would qualify as a prebiotic. Yes, it is a real thing, they have a fully organized scientific group! To be classified as a prebiotic the following criteria needs to be met (4),

  1. Selectively fermented by intestinal microorganisms

  2. Selectively targeting and stimulating the growth and activity of beneficial bacteria

  3. Non-digestible and resistant to breakdown by enzymes (digestion) in the human

The first two requirements help separate prebiotics from dietary fibers, as not all dietary fibers are fermentable by your gut biome. These fibers feed the healthy bacteria in your gut, maintaining, and improving your gut biome health, which in turn leads to plenty of health benefits for you! We will discuss those in greater detail later.


Next up, Probiotics! This one you have probably heard about more often in the news and mentioned on certain products in the supermarket. You can purchase probiotic specific supplements though they are often found in supermarkets in fermented products (kimchi, sauerkraut), dairy products (yogurt, Kefir), soy products (miso, tempeh) and the more recently popular kombucha. For those that are not a huge fan of any of the foods I just listed, there are also plenty of amazing probiotic supplements out there as well.

Pickled Vegetables in bowls on wood table

While prebiotics are the food for you gut biome, probiotics are the living microorganisms that support and help your current gut biome. Probiotics have also been specifically defined as, “live microorganisms which when consumed in adequate amounts confer a healthy benefit to the host”. The key thing there is, “benefits to the host”, which is you! The consumption of probiotics has been heavily researched to improve digestive health (5), mental health (6), chronic inflammation (7,8), immune health (9), amongst many other things. While it is true that probiotics can do wonders for your health, not all probiotics products are created equal. The biggest issue is getting the live probiotics to their destination in your gut, alive! On their journey, they must pass through your stomach which is highly acidic and then through your duodenum which is highly basic, which can lead to the breakdown of your new microbial friends.  When it comes to probiotics, it is more of a numbers game, with the more you take in the better the chance of live cultures reaching your gut in one piece.


Lastly, we have postbiotics, which I am going to assume just about none of you have heard of before as they have only recently been discovered and are now being further researched. Postbiotics are probiotics (healthy gut bacteria) that have been immobilized. It is suggested that these immobilized bacteria can help restore your natural intestinal microbiome and have positive health benefits similar to probiotics (9). You likely won’t see any advertising for postbiotics anytime soon, but it is good to be in the know.

Health Benefits

As I mentioned before, there is an abundance of data supporting the important of a healthy gut microbiome and how an unhealthy gut can negatively affect your health, with an improved gut microbiome having positive health benefits in many areas, including,

  • your weight (10,11),

  • heart health (12,13,14,15),

  • blood sugar (16,17),

  • blood pressure (18),

  • brain health (19, 20)

  • Immune health (21)

  • and not unexpectedly, your gut health (Irritable bowel syndrome, inflammatory bowel syndrome etc.) (22,23).

Closing Thoughts

While we have learned a lot over the last decade about gut health, there is still a lot we don’t know but thankfully new research is coming out almost every day. So, what is the best way to go about keeping a healthy gut?  I would suggest starting with a healthy diet, which if you are eating your fruit, vegetables and healthy grains will cover having pre-biotics in your diet. As for probiotics, yogurt, pickled foods and kombucha are great additions but it can’t hurt to add a probiotic supplement to your routine as well.  



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  2. Guarner F, Malagelada J-R. 2003. Gut Flora in health and disease. Lancet. 361(9356): 512-519.

  3. Beaugeria L, Petit J-C. 2004. Antibiotic-associated diarrhoea. Best Practice & Research Clinical Gastroenterology. 18(2):337-352.

  4. Gibson G, Hutkins R, Sanders M, Prescott S, Reimer R, Salminen S, Scott K, Stanton C, Swanson K, Cani P, Verbeke K, Reid G. 2017. Expert consensus document: The international Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nature reviews. Gastroenterology & Hepatology. 14(8): 491-502.

  5. Braga, V. L., dos Santos Rocha, L. P., Bernardo, D. D., de Oliveira Cruz, C., & Riera, R. (2017, November–December). What do Cochrane systematic reviews say about probiotics as preventive interventions? Sao Paulo Medical Journal135(6), 578–586

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