What Is My Microbiome?

Every time you turn on the TV, it seems like there’s a new commercial for something that contains “friendly bacteria” good for “gut health.” You scour the Internet to find out what makes bacteria friendly and come across the term “microbiome.” Micro wha?

All of us have a microbiome, and it’s key to good health. Here’s why it’s an important discovery, especially for people with digestive diseases.

Microbiome defined

The microbiome refers to the genetic material of all the microbes that live on and inside the human body. That includes bacteria, fungi, viruses, and protozoa.

The microbiome is a complex system. Research, such as studies conducted by the Human Microbiome Project, estimates the microbiome has about 3.3 million unique genes. The whole human genome has about 23,000 genes. Researchers consider it an essential body organ.

While we usually think of bacteria as something to get rid of, bacteria within the microbiome work to keep us healthy.

These “friendly” bacteria help you digest food, regulate your immune system, and produce some vitamins, including B12, thiamine, riboflavin and vitamin K. Some good bacteria act as soldiers, forming an army to fight off disease-causing bacteria.

What does my microbiome have to do with GI health?

The microbiome can house around 1,000 different species of bacteria. Some believe changes in the gut microbiome are associated with autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, muscular dystrophy and multiple sclerosis. Some studies have suggested microbiomes with less diverse or lower number of bacteria are associated with conditions such as inflammatory bowel disease and even asthma.

What do gastroenterologists know about it now?

Researchers only recently recognized the microbiome — in the late 1990s. That means physicians and researchers are only beginning to study the relationship between the microbiome and certain diseases. For example, we know that people with certain diseases don’t have as many different types of bacteria, but whether that imbalance actually causes disease remains unclear. Researchers are investigating the answer to this question.

Physicians do know, however, that correcting microbiome imbalance can improve health in some conditions. Doctors have used fecal microbiota transplantation (FMT) to restore healthy bacteria in the colon to cure Clostridium difficile infections. Doctors have tried FMT to treat ulcerative colitis, constipation and irritable bowel syndrome.

What are gastroenterologists trying to learn?

Researchers are studying ways to use microbiome manipulation as a treatment or cure for disease. Studies include use of antibiotics to kill “bad” bacteria, prebiotics and probiotics to encourage growth of “good” bacteria and use of FMT to treat certain conditions.

Doctors and researchers at University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine are currently studying the gut microbiome to determine which bacteria may contribute to inflammatory bowel disease (IBD).

Using stool samples collected from both families with multiple members diagnosed with IBD and healthy individuals, researchers model the effects of IBD and healthy gut bacteria in germ-free mice. The results help researchers decipher between healthy bacteria and IBD-causing bacteria.

What does this have to do with yogurt?

The probiotics found in yogurt, kimchi, kefir and other fermented foods are actually living bacteria and yeasts. Different types of probiotics have different benefits; for example, Lactobacillus strains may help alleviate diarrhea.

Researchers have investigated the diet’s influence on the gut microbiome for decades. Nobel laureate Elie Metchnikoff introduced the concept of probiotics in a report, published in 1907, that linked the longevity of Bulgarians with the consumption of fermented milk, aka yogurt.

Other studies, however, have shown little benefit from probiotics. Two recent studies published in The New England Journal of Medicine looked at the use of probiotics in children with gastroenteritis. The studies showed that two particular probiotics had no benefit for North American children with acute gastroenteritis.

The American Gastroenterological Association reports that probiotics are generally safe for healthy children and adults. However, use them with caution in children with chronic illnesses or have compromised immune systems. The two studies, AGA says, focused on a specific population and two specific products, which means results may not apply to all children and all probiotics.

While advertisements claim probiotics help with everything from weight loss to sleep quality, it’s best talk with your doctor to determine which — if any — probiotics are right for you. They’ll have the best advice on how to keep your microbiome as diverse and healthy as possible.

Reviewed by Dr. Chris Fourment, 1/28/2019.

Resources

//assets.gialliance.com/Images/Sites/G/GI-Alliance/MasterPage/889495.pdf https://ep.bmj.com/content/102/5/257 https://www.uhhospitals.org/for-clinicians/articles-and-news/articles/2018/01/investigating-treatments-for-inflammatory-bowel-disease https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539293/