Microbiome Series Part 2 – Pre, Pro, and Postbiotics
Let’s define a few terms first before we jump all the way into how we can improve our microbiomes. As we reviewed in the introduction, there are many ways to feed and grow the
microbiome. You have likely seen probiotics in new products from supplemental capsules to face creams and protein powders. But what exactly do they do and why do they work? To understand that, we not only need to understand probiotics but also prebiotics and postbiotics. Keep in mind this simple equation as we move forward – Prebiotics + Probiotics = Postbiotics.
Prebiotics are defined as any substance that feeds a microbe and confers a health benefit. Typically these are thought of as dietary fibers from foods like leafy greens, beans, whole grains, oats, and onions; however, the definition has expanded to include lesser known substances such as beta glucans and foods such as chicory root, chocolate, and mushrooms. Fiber is a massively important subject and one that will be later awarded an entire blog post of its own, but for now just know that it is a non-starchy carbohydrate that passes through the entirety of the digestive tract fully intact as humans lack the enzyme to digest fiber on our own. Luckily, our microbes are professional fiber digesters. Some fiber is digested by our microbes while others are indigestible and help to regulate stool consistency and blood sugar.
Probiotics are live microorganisms that confer a health benefit to their host. As mentioned earlier, these are found in a variety of products in stores as well as fermented foods. These often list one or several different strains of microbe and are measured in CFU’s (colony forming units). Supplements often contain anywhere from 10,000 CFU’s to 60 billion CFU’s. Fermented foods, which contain probiotics, include yogurt, kefir, sauerkraut, kimchi, pickles, miso, or tempeh. These microbes are ingested and enter the gut, but they do not simply take up residence and start living there – they are mostly transient, meaning that they enter the intestines and travel along it, but for the most part they do not stay and take up residence in the gut microbiome. Instead, they help our bodies by regulating the existing microbiome through a variety of mechanisms – one of
those being postbiotics.
Postbiotics are the newest kid on the block in terms of understanding and research. Postbiotics are the product created from the digestion done by a probiotic to a prebiotic. Prebiotic + Probiotic = Postbiotic. Postbiotics are also known as short chain fatty acids (SCFAs) and while there are many, the 3 most important are butyrate, acetate, and propionate. The more recent scientific findings suggest that the benefits of a microorganism is not necessarily due to the type of bacteria or specific strain that is residing in the gut, but the type of postbiotic it creates. All 3 SCFAs are beneficial, but some are better than others and achieving a certain ratio has been found to be important. One of the main reasons our microbiomes are so important is because of postbiotics. SCFAs produced have a wide variety of functions, but some of the main ones include feeding local colon cells, maintaining a healthy mucus layer in the intestinal lining, reducing leaky gut, maintaining healthy immune function, regulating mood, and much more. We are still scratching at the surface of the potential of what SCFAs can do for us, but all signs are pointing to important clinical uses.
A good analogy for all of this is tourism. Probiotics are the tourists here, our guts are the shops/attractions, the money spent is postbiotics, and the local economy is our health. The tourists (probiotics) enter our town (intestines) and stop along the way, paying for rides (postbiotics) and contributing to and growing the local economy (health). They may even stay the night and pay even more money. Some tourists might even stay forever and live there, further boosting the town’s population and quality.
As we continue our blog series, we will learn more about how exactly we can improve our “tourism” and improve our health and wellbeing through nurturing our microbiomes!
Gibson GR, Hutkins R, Sanders ME, et al. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017;14(8):491-502. doi:10.1038/nrgastro.2017.75
Dr. Conway’s approach to patient care begins with talking about the gut. The quality and variety of food we put in our bodies is directly connected to the quality of our health. He enjoys supporting patients with a variety of complaints including gas, bloating, abdominal pain, food sensitivities/intolerances, weight fluctuations, and more. Dr. Conway, a naturopathic doctor in Portland, earned his doctorate from the National University of Natural Medicine in Portland, Oregon. Learn more about Dr. Andrew Conway.