(Tiny Tips) – Gut Microbiome – Although it may not be the most pleasant thought, our bodies have bacteria and other microbial communities in and on our skin. Also called microbes, these microorganisms play important roles in many body functions.
In addition to bacteria, fungi, parasites, and viruses also make up the microbiome, with bacteria being the most studied. Scientists estimate that there are 100 trillion microorganisms living in the human body, most of which are in our intestines.
The microbiome is made up of beneficial and potentially harmful microorganisms. Most are friendly and have a symbiotic relationship with the body, meaning both the microbes and the body benefit. However, some microorganisms are pathogenic, meaning they can cause disease. In a healthy human body, both microorganisms coexist and live in peace.
However several factors can disrupt this balance, including infections, dietary changes, and long-term antibiotic use. This disruption to the microbiome can make a person more susceptible to disease.
Different Microbiomes in the Body
Different microbial communities live in the human body, each forming its own microbiome:
Gut Microbiome Most of the microorganisms in the body are found in the gut. The greatest amounts are found in the small and large intestines. The gut microbiome is the most discussed and studied group of microorganisms in the body. Research suggests that more than 1,000 species of bacteria may be present in the human gut microbiome.
The gut microbiome plays an important role in digestion and maintaining a healthy immune system. Disturbances in the gut microbiome can lead to conditions such as obesity, inflammatory bowel disease, diabetes, eczema, celiac disease, and psoriatic arthritis.
Skin Microbiome The skin surface also contains a diverse microbiome that interacts with the body’s immune system and affects skin health. The skin is home to millions of bacteria, fungi, and viruses. Many of these microorganisms are friendly and work with the body to prevent pathogens and infections from entering and speed wound healing. When there is disharmony between friendly and unfriendly bacteria on the skin, it sometimes leads to certain diseases, such as acne and atopic dermatitis (a form of eczema).
Oral Microbiome The oral cavity contains over 700 species of bacteria and is home to the second largest group of microorganisms after the gut. The microbiome in your mouth plays an important role in digestion, oral health, and the overall health of your body.
Reproductive Microbiome The reproductive microbiome has not been studied as extensively as the gut, skin, and mouth, but there is evidence that a diverse range of microbes live in both male and female reproductive organs. In women, the reproductive microbiome can be very dynamic and often changes due to factors such as age, menstruation, and pregnancy. Little is known about the male reproductive microbiome, but scientists believe it can have a significant impact on reproductive function and performance in both sexes.
Symptoms of an Unhealthy Gut
Research shows that signs of an unhealthy gut can be seen throughout the body:
Gastrointestinal Discomfort Frequent stomach discomfort, manifested by gas, bloating, abdominal pain, diarrhea, and constipation, may be a sign of irritable bowel syndrome (IBS). A study suggests that an imbalance in the gut microbiome may be a factor in irritable bowel syndrome in some people.
Fatigue Chronic fatigue syndrome, a condition characterized by extreme fatigue that lasts at least six months, may be related to an imbalance in the gut microbiome, researchers say. They also found that almost half of people with chronic fatigue syndrome also had irritable bowel syndrome.
Weight Gain There is evidence of a link between obesity and disruption of the gut microbiome. Manipulating the gut microbiome may be a strategy to promote weight loss and prevent obesity in humans, a study suggests.
Autoimmune Diseases According to one study, a bacterium called Bacteroides fragilis produces a protein in the gut that triggers certain autoimmune diseases, such as ulcerative colitis rheumatoid arthritis, and multiple sclerosis.
Skin Conditions Imbalances in the gut microbiome can lead to various skin diseases, including acne, atopic dermatitis or eczema, and psoriasis.
.Allergies An unhealthy gut microbiome may lead to allergies, including food allergies and skin sensitivities.
Mood Disorders There is a link between gut health and the brain, and disruption of the gut microbiome and inflammation in the central nervous system may lead to mood disorders such as depression and anxiety.
Migraines The connection between the gut and the brain may also play a role in migraines, although the link is not fully understood.
How to Maintain or Rebuild a Healthy Gut Microbiome
If you are concerned that your gut microbiome may be imbalanced, talk to your doctor. Your doctor can help you identify possible causes of your symptoms and develop a treatment plan to help you feel better.
There are several strategies to restore a healthy gut microbiome.
Increase your fiber intake. Diet plays an important role in maintaining gut health. When the gut microbiome is imbalanced, one way to restore intestinal homeostasis is to consume more fiber. Fiber can only be broken down and fermented by microorganisms in the large intestine. This fermentation process releases short-chain fatty acids (SCFA), which lowers the pH of the colon. A lower pH creates an environment that prevents the growth of certain harmful bacteria, such as Clostridium difficile.
Foods that promote increased levels of SCFA (sometimes called prebiotics) include raw foods of garlic, onions, leeks, asparagus, bananas, seaweed, dandelion greens, and Jerusalem artichokes. It’s important to introduce prebiotic foods into your diet slowly, as sudden intake can cause gas and bloating.
Consume more probiotics. Probiotics contain live organisms, usually specific strains of bacteria, that add healthy microorganisms directly to your gut. Foods that contain probiotics include yogurt, kefir, tempeh, kombucha, kimchi, miso and sauerkraut.
Probiotics can also be taken in supplement form. However, like all dietary supplements, these supplements are not fully regulated by the U.S. Food and Drug Administration like drugs. This means that probiotic pills may not contain the probiotic content stated on the label, or the bacteria may still be alive and active when consumed. It’s best to talk to your doctor before trying any probiotic supplement. A healthcare provider can help you decide which probiotic supplement to try and recommend reputable brands. You can also check out reputable aftermarket supplement testing companies to find quality brands and products.
Maintain an exercise routine. Physical activity improves the health of your gut bacteria. One small study found that an exercise program of just six weeks had a positive impact on participants’ gut microbiomes.
Talk to your doctor about medications that may affect your gut microbiome. Certain medications can negatively affect gut health. One of the biggest disruptors of your gut microbial balance is antibiotics. According to one review, antibiotic use can have multiple negative effects on the gut microbiome, including reduced biodiversity, altered metabolic activity, and the growth of antibiotic-resistant microorganisms.
Further research found that several commonly used medications can alter the gut microbiome—some positively, some negatively. Proton pump inhibitors are medications used to treat acid reflux and can negatively impact the gut microbiome. On the other hand, medications used to treat high blood pressure and high cholesterol, including diuretics, beta-blockers, and statins, are associated with healthier gut bacterial composition and function.
If you have questions about how the medications you take may affect your gut microbiome, talk to your doctor.
On the Horizon: Research on the Gut Microbiome
The gut microbiome remains a promising area of research with many opportunities:
Home Tests A number of startups have begun selling home testing kits to consumers, claiming they map the microbiome. Many companies also promise that vitamins and probiotics will help correct your microbiome, improve disease symptoms, and aid weight loss. However, there has not been enough research into the accuracy of these tests and how to use the information obtained. If you have questions about at-home testing, talk to your doctor.
Fecal Transplants A fecal transplant is the transfer of feces from a healthy person into the gastrointestinal tract of another person to treat gastrointestinal problems. The procedure is most commonly used to treat recurrent severe Clostridium difficile colitis, a condition that includes diarrhea, abdominal cramps, and fever. This condition is often the result of antibiotic treatment, causing the harmful bacteria Clostridium difficile to overgrow in the intestines and not respond to antibiotics and other measures.
Fecal transplants may help treat inflammatory bowel disease, but more research is needed, a review of research suggests. The same review also suggests that fecal transplants could be used in the distant future to treat other chronic conditions such as obesity, chronic fatigue syndrome, fibromyalgia, metabolic syndrome, and multiple sclerosis.
Editorial Sources and Fact-Checking
- Amon P, Sanderson I. What Is the Microbiome? Archives of Disease in Childhood — Education and Practice. September 2017.
- The Microbiome. Harvard T.H. Chan School of Public Health.
- Valdes A, Walter J, Segal E, Spector T. Role of the Gut Microbiota in Nutrition and Health. The BMJ. June 2018.
- Byrd AL, Belkaid Y, Segre A. The Human Skin Microbiome. Nature Reviews Microbiology. January 2018.
- Eisenstein M. The Skin Microbiome and Its Relationship With the Human Body Explained. Nature. December 2020.
- Deo PN, Deshmukh R. Oral Microbiome: Unveiling the Fundamentals. Journal of Oral Maxillofacial Pathology. Jan–April 2019.
- Rowe M, Veerus L, Trosvik P, et al. The Reproductive Microbiome: An Emerging Driver of Sexual Selection, Sexual Conflict, Mating Systems, and Reproductive Isolation. Trends in Ecology & Evolution. March 2020.
- Menees S, Chey W. The Gut Microbiome and Irritable Bowel Syndrome. F1000 Research. 2018.
- Nagy-Szakal D, Williams BL, Mishra N, et al. Fecal Metagenomic Profiles in Subgroups of Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Microbiome. April 2017.
- Davis CD. The Gut Microbiome and Its Role in Obesity. Nutrition Today. Jul-Aug 2016.
- Stewart L, Edgar JDM, Blakely G, Patrick S. Antigenic Mimicry of Ubiquitin by the Gut Bacterium Bacteroides fragilis: A Potential Link With Autoimmune Disease. Clinical & Experimental Immunology. August 2018.
- Huihui XU, Liu M, Cao J, et al. The Dynamic Interplay Between the Gut Microbiota and Autoimmune Diseases. Journal of Immunology Research. October 2019.
- Salem I, Ramser A, Isham N, Ghannoum MA. The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Frontiers in Microbiology. July 2018.
- Pascal M, Perez-Gordo M, Caballero T, et al. Microbiome and Allergic Diseases. Frontiers in Microbiology. July 2018.
- Clapp M, Aurora N, Herrera L, et al. Gut Microbiota’s Effect on Mental Health: The Gut-Brain Axis. Clinics and Practice. September 2017.
- Arzani M, Jahromi SR, Ghorbani Z, et al. Gut Brain Axis and Migraine Headache: A Comprehensive Review. The Journal of Headache and Pain. February 2020.
- Prebiotics, Probiotics, and Your Health. Mayo Clinic. February 27, 2021.
- Allen JM, Exercise Alters Gut Microbiota Composition and Function in Lean and Obese Humans. Medicine & Science in Sports & Exercise. April 2018.
- Ramirez J, Guarner F, Fernandez LB, et al. Antibiotics as Major Disruptors of Gut Microbiota. Frontiers in Cellular and Infection Microbiology. November 2020.
- Forslund SK, Chakaroun R, Zimmermann-Kogadeeva M, et al. Combinatorial, Additive, and Dose-Dependent Drug-Microbiome Associations. Nature. December 2021.
- Fecal Transplantation (Bacteriotherapy). Johns Hopkins Medicine.
- Choi HH, Cho YS. Fecal Microbiota Transplantation: Current Applications, Effectiveness, and Future Perspectives. Clinical Endoscopy. May 2016.