Focus on Gut Health: What is your Microbiome?
Part 1:
The world’s most complex ecosystem could be living closer than you ever imagined!
You may have heard the term “microbiome” being thrown around in the latest article of your favorite health magazine or by a social media influencer in your daily internet scroll, but have you taken the time to understand what this term means? If not, read on and discover with me the fascinating world of the human microbiome and ways to prioritize the health of your microbiome in your daily life. (This is part 1 of a 3-blog series on your microbiome.)
The term microbiome refers to the complex ecosystem of microscopic organisms that live on and within our bodies—from our skin to our mouth and even our digestive tract. In fact, our digestive microbiome has been described as “The most complicated ecosystem that has been discovered by man.” (Blaser) Our digestive microbiome is defined by scientists as the billions of bacteria, viruses, protozoa and their DNA fragments that occupy our digestive tract (mostly in our large intestine). Twenty years ago, these microbes were traditionally thought of as “bad” and were considered something of a nemesis in scientific thinking. Here’s the interesting thing: that idea has now been entirely flipped on its head and our microbiome is now thought to be the one of the leading drivers of both wellness AND disease states in our bodies.
The bacteria that occupy our microbiomes assist our body in many ways. You can think of these as jobs or skill sets of various species of bacteria that live in large intestine. Here are a handful of ways your digestive bacteria support your body and its daily functions:
The bacteria in your digestive tract can:
Boost your natural immune response. Did you know that 70% of your body’s entire immune system is found in your digestive tract? That’s right, your immune system and your digestive system are uniquely intertwined with much of your body’s defense army sitting at-the-ready in areas called Peyer’s patches which run the length of the small intestine. These little islands of densely packed immune cells combined with several other unique characteristics of immune protection such as proper stomach acid and pH, healthy mucosal lining of your digestive tract, and the trillions of bacteria living in your microbiome serve as your body’s first line of defense to foreign invaders. What is fascinating is that your body uses the bacteria living in your microbiome to assist with immune health as they directly communicate with your immune system to attack pathogens as they enter your body through the digestive tract.
Promote proper digestion and absorption: Your body’s digestive tract cannot process every single thing you ingest on its own. Your digestive tract relies on the bacteria in your large intestine to break down foods like complex carbohydrates (think fiber-rich starchy vegetables). The fermentation of these fiber-rich foods by your microbiome becomes a food source for the bacteria living in your colon, and they in turn produce Short Chain Fatty Acids (SCFAs) that are directly linked to reduced inflammation, improved blood sugar and the prevention of chronic disease. More on this in Part 3 of this series when we talk about ways to improve the health of your microbiome.
Manufacture chemical messengers in your body: from hormones to neurotransmitters, your gut bacteria can profoundly influence the levels of important chemical messengers in your body such as GABA, Norepinephrine, Dopamine, and Serotonin. In fact, your gut (and the bacteria living there ) manufactures around 95% of your body’s serotonin. Serotonin is an important neurotransmitter that not only has the capacity to influence gut motility but is also directly linked to mood, appetite control and mental well-being.
Assist in the breakdown of medications for proper removal and elimination from the body. Much like the idea that your body cannot digest everything you eat on its own, your body’s detoxifcation organs also look to your microbiome for help. These organs which include your liver, kidneys, lungs and skin cannot eliminate toxins that you create (think hormone by-products) or ingest all on their own. Your digestive tract, and primarily the bacteria living in your large intestine, assist your body in the breakdown of toxic metabolites of drugs and other chemicals that you have ingested and even assist in the breakdown and elimination of hormones and their by-products (think estrogen) for proper removal from the body.
Manufacture vitamins and other nutrients: Your bacteria are constantly giving back to your body in the form of creating vitamins (such as B12 and vitamin K) and amino acids (the building blocks of proteins) which are vital for proper function of every cell in your body.
The number of researchers focused on the microbiome has climbed exponentially in the past decade. Through efforts like The Human Microbiome Project, we are learning that just like our own physical bodies are unique, no two microbiomes are identical. What does this mean for you? It means that your microbiome and my microbiome can be (and likely are) quite different. This difference is based on many factors including food choices, lifestyles, medications, our environment, and even the way we were born and our mother’s own microbiome! Researchers are also discovering that the health of our microbiome could directly impact the development of disease states in our bodies. To date, the diseases that have been linked to an imbalanced microbiome are quite extensive and may surprise you. This includes diseases such as Alzheimer’s, Parkinson’s, obesity, osteoporosis, diabetes, autoimmune disorders, and mood disorders. Many people have been affected personally or have loved ones who have been affected by these diseases. Although the health of our microbiome is not the singular cause or reason that these diseases manifest, it is important to understand all of the potential drivers of disease in the human body and to work where we can to support and balance our body as we age.
So where can things go wrong? Scientists are just beginning to discover what bacteria in our microbiome create a healthy environment and what bacteria are signs of an unhealthy or inflamed gut environment. Stay tuned for Part 2 of this Educational Series to learn about ways we may harm the health of our microbiome.
References:
C. Jung et al. Peyer's Patches: The Immune Sensors of the Intestine. Int J Inflam. 2010; 2010: 823710.
M. Blaser. Missing Microbes: How the Overuse of Antibiotics is Fueling our Modern Plagues.
Francino MP. Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances. Front Microbiol. 2016 Jan 12;6:1543.
E Mayer. The Mind-Gut Connection: How the Hidden Conversation Within Our Bodies Impacts Our Mood, Our Choices, and Our Overall Health.
M Gershon. The Second Brain: A groundbreaking new understanding of nervous disorders of the stomach and intestine.
The National Institute of Health’s Human Microbiome Project. Access here: https://www.hmpdacc.org/
Yeoh YK, Zuo T, Lui GC, et alGut microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19. Gut 2021;70:698-706.