Have you ever wondered what is really going on in your gut? The simple answer is that you have characters called microbes living rent-free in your intestines, but let’s take a deeper dive into what these little guys do to keep digestive processes running smoothly.

What is the gut microbiome? 

The gut microbiome is a large community of microbes housed in your large intestine, including bacteria, fungi, parasites, and viruses. These microbes are initially introduced to the body at birth, and factors such as the method of delivery, breastfeeding versus formula feeding, and other influences determine the first microbes that reside in the large intestine. By age two to three, a child’s gut microbiome stabilizes and resembles an adult’s.

What role does the gut microbiome play in health? 

Within the gut microbiome, these microbes each have a distinct job that significantly benefits areas of human health, including digestion, immune response, and neurological function.

Digestion

• Bacteria in the gut microbiome can break down or metabolize fiber and non-digestible carbohydrates into short-chain fatty acids (SCFAs). SCFAs are beneficial for keeping the gut lining strong by feeding the cells that line the gut.
• Additionally, bacteria can synthesize vitamins such as vitamin B12, vitamin B1, vitamin B2, biotin, and vitamin K. It has been estimated that half the daily requirements for vitamin K can be provided by the microbes within the gut.

Immune system  

• The gut lining contains attachment sites that enable pathogenic or “bad” bacteria to adhere to and potentially damage the cells within. “Good” bacteria can compete for these sites, preventing the invasion of pathogenic bacteria.
• Good bacteria can also produce SCFAs and antimicrobial substances called bacteriocins, which inhibit the growth of pathogenic bacteria.

Nervous system 

• Neurotransmitters are chemical messengers that transmit signals between nerve cells in the brain and throughout the nervous system, helping the nervous system function properly. In the gut microbiome, bacteria can produce neurotransmitters, one of which is Y-aminobutyric acid (GABA). GABA helps regulate gastrointestinal functions like gut motility and gastric emptying.
• Another neurotransmitter that bacteria can produce is serotonin. Similar to GABA, serotonin helps with gut motility.
• Dopamine is a third neurotransmitter that bacteria can produce within the gut. Besides supporting gut motility and gastric emptying, dopamine may also play a role in regulating electrolyte absorption.

The role of the gut microbiome in our overall health extends far beyond what is written here. It is quite remarkable what these tiny organisms can do in our digestive system. However, much like ourselves, the microbes in our gut are influenced by the events and experiences of daily life.

What factors affect the gut microbiome? 

• Geographical location
• Chemical exposure
• Antibiotics
• Genetics
• Stress levels
• Sleep quality
• And… Diet!!

The factors outlined above affect our gut microbiome and its functionality; however, diet is the main factor over which we have control. Therefore, our daily food choices are important decisions that can substantially support and enhance the health and functionality of our gut microbiome.

What foods can you incorporate to support your gut microbiome?

Eat foods that contain prebiotics. A prebiotic is a source of fiber that is “food” for our gut bacteria, helping them stay actively doing their jobs in our intestines. Foods that contain prebiotics include apples, oats, onions, lentils, cashews, cabbage, and more. Fortunately, the dining halls at UGA make eating foods that benefit the gut microbiome easy! Here are some ideas of foods you can eat at each meal:

• Breakfast options – Wheat Bran and Oats Bagel, banana, Special K with Red Berries Cereal, Overnight Oats with Chia Seeds and Soymilk, Tofu Scramble
• Lunch options – Kale Super Salad Blend, Lima Beans, Lemon Garlic Hummus, Brown Rice, Veracruz Garbanzo Beans
• Dinner options – Green Beans with Shiitake Mushrooms in Black Bean Garlic Sauce, Blackened Tofu with Red Beans and Brown Rice, Kiwi and Orange Slaw, Cherry Tomatoes, Minced Garlic

The bottom line

Now that you really know what is going on in your gut, hopefully, you have a new-found fascination for your gut microbiome! Those little characters living rent-free in your intestines are working hard to keep your digestion, immune system, and nervous system up and running smoothly. Help those little guys out by adding a banana or some kale to your next plate!

References

Ahn J, & Hayes B. Environmental influences on the human microbiome and implications for noncommunicable disease. 2021 April 1. Annu Rev Public Health. Internet: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8641399/

Bull M, Plummer N. Part 1: The human gut microbiome in health and disease. 2014 December 13. Internet: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566439/

Canadian Digestive Health Foundation. Prebiotics vs dietary fibre. 2023 April 18. Internet:  https://cdhf.ca/en/prebiotics-vs-dietary-fibre/

Cleveland Clinic. Gamma-aminobutyric acid (GABA). 2022 April 25. Internet: https://my.clevelandclinic.org/health/articles/22857-gamma-aminobutyric-acid-gaba

Cleveland Clinic. Gut microbiome. 2023 August 18. Internet: https://my.clevelandclinic.org/health/body/25201-gut-microbiome

Gomaa E. 2020 November 02. Human gut microbiota/microbiome in health and diseases: a review. Internet: https://link.springer.com/article/10.1007/s10482-020-01474-7#ref-CR40

Harvard School of Public Health. The microbiome. 2024. Internet: https://nutritionsource.hsph.harvard.edu/microbiome/#diet-microbiota

Mororwitz MJ, Carlisle E, Alverdy JC. Contributions of intestinal bacteria to nutrition and metabolism in the critically ill. 2011 August. Internet: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144392/

Mittal R, Debs LH, Patel AP, et al. Neurotransmitters: the critical modulators regulating gut-brain axis. 2017 April 10. Internet: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772764/#:~:text=These%20neurotransmitters%20are%20able%20to,immune%20system%2C%20and%20the%20microbiome.

Rastelli M, Cani PD, Knauf C. The gut microbiome influences host endocrine functions. 2019 May 19. Internet: https://academic.oup.com/edrv/article/40/5/1271/5487987