Health Resource: Introduction to the Microbiome

By John Sepp

The microbiome is a diverse collection of bacteria that live on and inside our bodies. It has tremendous implications for our health. However, most people, and even many researchers, have a limited understanding of it. With probiotics becoming increasingly popular and the phrase “gut health” becoming more familiar, it’s a good idea to become familiar with these communities of microbes that live inside our bodies. In this article, I will provide an introduction to the microbiome along with an overview of its relevance to our health. 

The microbiome consists of trillions of bacteria throughout our stomach and intestines.  Each person has a unique network of microbiota (the bacteria that live in our bodies), which is determined by factors such as  DNA, the use of medications, environment, and diet. A common misconception is that all forms of bacteria are harmful to us, and must be cleared out by our immune systems. Yet, quite the opposite is the case with our gut microbiota, where many forms of symbiotic relationships with these bacteria exist.  

Most notably, the different kinds of bacteria in our gut play an integral role in breaking down fiber, sugars, carbohydrates, and more macronutrients. As this occurs, bacteria release short chain fatty acids (SCFAs) as a byproduct, along with hydrogen gas and countless other “metabolites”.  SCFAs have shown great promise in preserving the integrity of the intestines, encouraging processes such as mucus production that protect against ulcers, colorectal cancer formation, and more.  This provides the bacteria in our gut with a rich selection of nutrients allowing them to release an optimal amount of beneficial metabolites, and making sure they are not overpowered by a select few harmful bacteria—this not only helps our digestion, but may be playing a significant role in preventing disease and promoting health.  

Currently, this is an extremely active area of research, with scientists trying to distinguish a connection between the compounds that specific bacteria produce as byproducts, and their downstream effects on our health.  One of the many ways researchers can test this is by supplementing one group of people with a very high-fiber diet, and another with a protein-heavy diet, and more to determine how macronutrients affect the population of gut bacteria and their resultant metabolites. This is why it is so important to provide the bacteria we harbor with a selection of the right kinds of nutrients that allow for a hospitable environment; the phrase “you are what you eat” now sounds more realistic!

Unfortunately, it is sometimes difficult to maintain a healthy homeostasis within our gut. Everybody can relate to having unpleasant digestive experiences, which can often be a result of consuming too much sugar, dairy, or in certain individuals, gluten. This starves most of the good bacteria of their nutrition that they are able to break down, allowing for an overwhelming invasion of harmful bacteria to colonize in our gut, wreaking havoc on our digestion. Until we address our eating habits, good bacteria are not able to outcompete and restore balance once again.

The immune system is closely connected to the microbiome, and anybody who has gone on vacation or traveled to a new place and experienced digestive discomfort has experienced an example of this. While the highest risk factor for traveler’s diarrhea is poor sanitation or food hygiene, the immune system may react angrily to what you ingest when it has been prepared differently or sourced from a different part of the world. The immune system also plays a role in closely monitoring our bodies, including the bacteria living in our gut. In ulcerative colitis, the immune system overreacts to normal intestinal microbes, producing sometimes unbearable levels of inflammation and pain.  

So, what can be done to minimize the risk of disease development, facilitate a healthy relationship with our gut microflora, and strive for overall health and well-being?  First, experts agree that a diverse diet is one of the most beneficial things you can do for promoting healthy gut bacteria. It greatly increases the makeup of bacteria so that certain families of harmful microbes cannot take over in the intestinal tract and cause problems. Next, while probiotics assist in colonizing the gut and outcompeting harmful bacteria, they generally do not appear to be as effective for producing long-lasting positive change as consuming a complete diet including fermented foods.  This is why it is important to search for prebiotics in conjunction with probiotics: inulin, for example, is a prebiotic that is a food source for these probiotic bacteria that allow them to have a better chance of surviving and colonizing in the gut rather than passing in and out. Lastly, in the case of conditions like ulcerative colitis, allergies, or Crohn’s disease, where our immune systems seem to be fighting against us, much of the research in the microbiome is focusing on the relationship between the immune system and gut bacteria in search of more concrete answers.  

Since nine hundred words on this topic is nowhere near enough to cover all the important aspects of the microbiome, I encourage you to look more into this fascinating area of human health, where we are in the early stages of research and groundbreaking discoveries are likely in the near future. 

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