Little universes of bacteria, fungi, viruses, and parasites live in and on your body. Known as microbiomes, these tiny worlds impact your overall well-being positively by working together to keep your health in balance. (1) When something throws one of those universes out of balance, your well-being suffers. One powerful microbiome is the one in your gut. This microscopic universe plays a role in balancing immunity, digestion, weight, and even mental health. 

What does the gut microbiome do?

The gut microbiome is in the digestive tract. It is a diverse environment containing about 100 trillion microscopic organisms. (2) These organisms serve many functions, including digesting your food, protecting the intestinal wall, and metabolism. (9)

Everyone’s gut microbiome is different. Your gut health begins before birth with bacteria and DNA passed on from your mother. (7) The diet you consume in infancy, whether breast milk or formula, continues the development of your gut microbiome. This continues to evolve throughout your life. Factors such as the foods you eat, medications you take, genetics, and age all determine the makeup of your gut microbiome. 

How it affects digestive health

Your gut microbiome keeps the lining of your intestines intact and helps protect the walls from cancer cells. (2) It breaks down products passing through to make sugar for energy and to balance glucose. When an imbalance in the gut microbiome occurs, it’s called dysbiosis. (4) Dysbiosis may cause your body to begin working against you. This can lead to various diseases in the digestive tract:

• H. pylori
• Small intestinal bacterial overgrowth (SIBO)
• Inflammatory bowel diseases like ulcerative colitis and Crohn’s disease
• Digestive issues such as diarrhea or constipation

How it affects weight

Obesity is an excess of body fat. It’s a chronic disease that affects a person’s quality of life and overall health. In the United States (12):

• 1 in 5 children are obese
• 2 in 5 adults are obese

An overgrowth of certain bacteria or lack of variety in the bacteria in the gut microbiome can contribute to obesity. (9) The microbes in the gut produce substances known as metabolites. (2) Metabolites are substances the body makes or uses when breaking down food, medicines, or tissue in a process known as metabolism. Your metabolism creates the energy needed for growth and maintaining your health. Metabolism also removes toxins from the body. (3) 

When dysbiosis occurs in the digestive system, the body’s metabolism does not work correctly. The imbalance changes hormones in the gut, which affects how the body stores fat. These hormones also regulate appetite and food intake. Changes to these contribute to increased body fat. (9) 

How it affects heart health

Cardiovascular disease is the number one cause of death in the United States. Every 33 seconds, someone dies from cardiovascular disease. (11) People with cardiovascular diseases may have more inflammation producing gut microbiome. (10) Dysbiosis damages the lining of the intestines by creating chronic inflammation. The inflammation allows the intestines to release more toxins into the bloodstream. (8) Cardiovascular diseases linked to dysbiosis in the digestive tract include:

• Hypertension: gut bacteria affects blood pressure regulation
• Heart failure: circulating toxins from leaking from intestines increase generalized inflammation
• Atherosclerosis: gut bacteria found in plaque that lines artery walls
• Myocardial infarction: increased severity of attack

How it affects diabetes

An imbalance of certain bacteria in the gut that helps produce energy is linked to Type 2 diabetes. The dysbiosis, in this case, causes impaired glucose tolerance. The body’s ability to regulate blood sugar with insulin decreases. This leads to blood sugars getting pushed higher (10) 

How it affects mental health

Similar to diabetes, a high number of Americans experience mental illness. Every year:  

• 1 in 5 adults experience mental illness 
• 1 in 6 children 6-17 years old have a mental health disorder 

Mental illness encompasses a variety of disorders, including:

• Anxiety
• ADHD
• Bipolar
• Borderline personality disorder
• Depression
• Psychosis 
• Schizophrenia

Mental illness is complex and not the result of a single event or cause. Genetics, environment, and lifestyle all factor into a person’s mental health. (14) 

The gut microbiome plays a role in producing and regulating neurotransmitters. Neurotransmitters are substances that send messages between nerve cells. (15) Dopamine and serotonin are neurotransmitters used in the balance of mental health. (13) Low levels of serotonin can contribute to depression. (15) When there is a lack of diversity in the gut microbiome, issues like anxiety, depression, schizophrenia, and bipolar disorder can occur. (15)

What to do to keep your microbiome healthy

The standard American diet contributes to many problems with the gut microbiome. Highly processed foods can change your gut microbiome with the amount of fat, sugar, and low fiber they contain. (6) The changes to the gut microbiome can trigger genetic shifts that get passed on to the next generation. (6) Dysbiosis occurs and triggers inflammation. Chronic inflammation leads to chronic diseases such as diabetes, obesity, and heart disease. 

• Sugar alternatives, such as aspartame and saccharin, change the microbiome balance. 
• Food additives, such as emulsifiers, reduce diversity in the microbiome. 
• Some restrictive diets, such as vegan, raw food, or gluten-free diets, are problematic due to their lack of microbiome diversity. (2)

Improving the gut microbiome can occur quickly with dietary changes. Researchers see changes within days to two weeks. (2) Take steps to balance your microbiome.

• Eat a variety of foods. Food variety keeps the microbiome diverse. A low diversity of organisms is a common theme in the health issues related to the microbiome. When there is diversity, the microorganisms work together to keep everything in balance.
• Limit consumption of processed foods. Several additives in processed foods can change the balance of the gut microbiome. Some of these additives trigger hormonal problems that lead to inflammation and chronic health issues. By limiting the number of processed foods you eat, you can help reduce gut inflammation.
• Keep things moving. Regular bowel movements turn over the old and bring in new microorganisms. Eat foods high in fiber, such as fruits, vegetables, beans, and legumes. Staying active and consuming water throughout the day will help to keep things moving along.
• Limit chemicals. Chemicals such as alcohol and tobacco act like pollutants in your system.  Chronic exposure to these chemicals will keep your microbiome from flourishing. Limit the use of these pollutants. Additionally, overuse of antibiotics can wipe out the good and bad bacteria. Limit the use of antibiotics to only when necessary.
• Prebiotics. Prebiotics are foods your digestive system cannot completely digest, but they nourish microorganisms in the gut. (16) Feed your microbiome with prebiotic foods:
  • Garlic
  • Onions
  • Bananas
  • Asparagus
  • Wheat and whole-grain products
  • Apples
  • Jicama
• Probiotics. Probiotics are live microorganisms that aid with digestion and bowel function. (15) Eating foods with probiotics helps keep the digestive tract healthy. The probiotics work with prebiotics to keep the microbiome in balance. Probiotic foods include:
  • Yogurt
  • Kombucha
  • Kefir
  • Sauerkraut
  • Kimchi
  • Buttermilk

Taking care of your gut microbiome is likely an area of your health that you never considered. But the trillions of microorganisms inside your digestive tract play an important in your overall well-being. You can keep the balance of your gut microbiome in check by eating a variety of foods, limiting processed foods, and avoiding toxins. The impact may change your life.

REFERENCES:

1. National Cancer Institute, NCI Dictionary of Cancer Terms. Microbiome. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/microbiome
2. Valdes, A., Walter, J., Segal, E., & Spector, T. (2018). Role of the gut microbiota in nutrition and health. BMJ, 361. DOI: https://doi.org/10.1136/bmj.k2179
3. National Cancer Institute, NCI Dictionary of Cancer Terms. Metabolite. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/metabolite
4. Cleveland Clinic. (April 16, 2024). Dysbiosis. https://my.clevelandclinic.org/health/diseases/dysbiosis
5. Corliss, J. November 1, 2023. How a healthy gut helps your heart. Harvard Health, Heart Health. https://www.health.harvard.edu/heart-health/how-a-healthy-gut-helps-your-heart
6. Shi, Z. (2019). Gut microbiota: An important link between Western diet and chronic disease. Nutrients, 11(10), 2287. DOI: 10.3390/nu11102287
7. Yao, Y., Cai, X., Ye, Y., Wang, F., Chen, F., and Zheng, C. (2021). The role of microbiota in infant health: From early life to adulthood. Frontiers in Immunology, 12. doi.org/10.3389/fimmu.2021.708472
8. Patterson, E., Ryan, P., Cryan, J., Dinan, T., Ross, R., Fitzgerald, G., & Stanton, C. (2016). Gut microbiota, obesity, and diabetes. Postgrad Medical Journal, 92(1087), 286-300. DOI: 10.1136/postgradmedj-2015-133285
9. Vetrani, C., DiNisio, A., Paschou, S., Barrea, L., Muscogiuri, G., Graziadio, C., Savastano, S., & Colao, A. (2022). From gut microbiota through low-grade inflammation to obesity: Key players and potential targets. Nutrients, 14(10), 2103. DOI: 10.3390/nu14102103
10. Tang, W.H., Kitai, T., & Hazen, S. (2017). Gut microbiota in cardiovascular health and disease. Circulation Research,120(7), 1183-1196. DOI: 10.1161/CIRCRESAHA.117.309715
11. U.S. Centers for Disease Control and Prevention. Heart Disease Facts, October 24, 2024. https://www.cdc.gov/heart-disease/data-research/facts-stats/index.html
12. U.S. Centers for Disease Control and Prevention. About Obesity, January 23, 2024. https://www.cdc.gov/obesity/php/about/index.html
13. Xiong, R., Li, J., Cheng, J., Zhou, D., Wu, S., Huang, S., Saimaiti, A., Yang, Z., Gan, R., & Li, H. (2023). The role of gut microbiota in anxiety, depression, and other mental disorders as well as the protective effects of dietary components. Nutrients, 15(14), 3258. DOI: 10.3390/nu15143258
14. National Alliance on Mental Illness. About Mental Illness. Mental Health Conditions. https://www.nami.org/about-mental-illness/mental-health-conditions/
15. National Cancer Institute, NCI Dictionary of Cancer Terms. Probiotic. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/probiotic
16. Catanese, L. (2024, May 15). Prebiotics: Understanding their role in gut health. Harvard Health Publishing. https://www.health.harvard.edu/nutrition/prebiotics-understanding-their-role-in-gut-health