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Know Your Gut Microbiomes?

What if I told you that, you were full of bacteria?

Don’t worry, this is nothing to be embarrassed or ashamed about, but it's true! Bacteria lives in us! I mean, if you didn’t have bacteria in your body, I would be concerned, but this is a good thing. Bacteria helps our body by continuously working, to maintain a healthy digestive system.

The human body contains trillions of species including, eukaryotic, bacterial, and archaea cells. As adults, these human microbiomes, make up about 90% of our body, while the other 10% are human cells. Microbes colonize in different locations throughout the body including places of the skin, throat, and gut. The largest collection of microbes are gut microbiomes, also known as microflora. Gut Microbiomes are communities of living bacteria within the gastrointestinal (GI) tract. They potentially can weigh up to 5 pounds of your body weight. (1) More specifically, intestinal bacteria are in both areas of the mouth and stomach, but predominantly in the small, and large intestinal regions. Human gut microbiomes play a significant role in the body. Its role is to work together with bacteria by promoting healthy digestion and absorption of nutrients, while working synchronously with the circulatory, endocrine, and nervous systems needed for survival.  

Several factors affect microflora and its composition. Everyone has a unique amount of gut microbiomes that are distinctive to their own body and continuously change throughout development. Beginning at birth, gut microbiomes begin to develop during infancy, and the number of ways to determine how many gut microbes are developed, vary upon different interaction factors within the first 3 years of life. This includes methods of birth delivery, such as vaginal or cesarean dependencies, hospitalizations or premature births, infant feedings such as, use of breast- or bottle-feeding methods, antibiotic usages, environmental exposures, and genetics, each play factors in forming the number of microbiomes developed in the gut.

As one grows from infancy to adulthood, it is possible for individuals to alter their gut microbiomes by what they consume from their diet and lifestyle. For example, if an adult consumes nutritious meals, full of leafy greens and fiber, the more of these gut microbiomes, which thrive on leafy greens, will begin to populate in the gut. When this happens, new healthy cravings develop and signal the endocrine system (the brain) to nourish the body with healthy leafy green foods. This is due to the higher production and presence of bacteria in the gut favoring the leafy green and fibrous meals. This same method can apply, when an adult consumes meals high in sugar, and fat or highly processed meals. This causes further gut microbiomes that thrive on sugar, fat, or greasy foods to become superior in the gut. Therefore, causing the body to crave foods high in sugar, fat, or highly processed foods.    

Understanding the complexities of gut microbiomes is vital as it plays a key role in health and disease. Colorectal Cancer (CRC) has been discovered as the third leading causes of cancer mortality in the United States and risks increase with age. (2) CRC is developed in the rectum of the GI tract, where colon polyps cells grow on the inner lining of the colon and potentially, develop into colon cancer. Epidemiologic studies have been shown that diet can help lower risk for CRC. An increase of fiber in the diet was associated with a decreased risk for CRC, while an increase of red meats and fat in the diet, commonly used in Western diets, was associated with an increased risk. (2) The association with dietary intake may be facilitated by gut microbiomes as they help to promote health in the lining of the gut by metabolizing fiber which then, produces short-chain fatty acids in forms of butyrate, a preferred colonic energy source and propionate, that was shown to downregulate pro-inflammatory cytokines in colonic macrophages. (2) Both which aid in lowering risk for Colorectal Cancer development.


So, now that you are a bit more familiar with your gut microbiomes, the next time you plan your trip to the grocery store, be sure to include nutritional food items, such as leafy greens and fibrous foods, your “healthy gut microbiomes” will thank you!  


Until my next post... Namaste!

Melissa Marie


1. Gropper SS, Smith JL, Carr TP. Advanced nutrition and human metabolism. 8th ed. Boston, MA: Cengage Learning; 2022.

2. Wroblewski LE, Peek RM, Coburn LA. The role of the microbiome in gastrointestinal cancer. Gastroenterol Clin North Am. 2016;45(3):543-556. doi: 10.1016/j.gtc.2016.04.010.


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