In the middle of a pandemic, you probably want to know how well your immune system is functioning. Even more important, what if anything can you do to support it? Scientists have found that the microbes in the digestive tract communicate closely with the brain. What’s more, they now have evidence that the gut microbiome also shapes your immune response.

The microbiota of the digestive tract (what used to be referred to as “gut flora”) has an important impact on almost every aspect of our health. However, it took gastroenterologists a long time to recognize that they should be paying attention to microbial abundance and diversity. Only a few decades ago, in the 20th century, doctors’ main concern about the microbiota was whether it would make you sick. They did recognize that when they prescribed antibiotics, it might upset the balance of microbes in the colon. But even there, it took a surprisingly long time to realize that the “pseudomembranous colitis” listed as a serious side effect of the antibiotic clindamycin was actually the sign that one type of bacteria, Clostridium difficile, was taking advantage of having the competition killed off.

Serotonin is a neurochemical that cells in the brain use to communicate with one another. It came to public attention when Eli Lilly introduced Prozac to treat depression (1986). Later, scientists found a great deal of serotonin in and around the gut. What was it doing there? As it turns out, the gut microbiota uses serotonin to communicate also. Not only do the various microbes talk to each other, they also signal the brain.

At least 70 percent of the immune cells in your body hang out near the digestive tract. In some cases, the microbes of the gut are separated from those first responders for infection by only a single wall of cells and a quantity of protective mucus. If we don’t nurture the microbiome, the protective mucus is disrupted, the single wall of cells may fail, and we develop leaky gut syndrome. Healthy signaling between the microbiota and the immune cells leads to a robust and appropriate immune response. Leaky gut, on the other hand, can lead to an alarm reaction from the immune system and may result in an autoimmune disease such as Crohn’s disease, rheumatoid arthritis, psoriasis or even asthma and eczema.

Nurturing the microbiome with plenty of whole vegetables and fruits can help it stay healthy. Fermented foods also seem to help (Cell, July 12, 2021). Conversely, a diet full of refined grains, sugar and meat, like the standard American diet, is not likely to bolster your microbiome. Because your microbiome shapes your immune response. when you really want to stay healthy, you need to pay attention to what you are eating, how it is grown and whether you are getting enough sleep and incorporating calming mindfulness into your life. A healthy lifestyle and the health of the soil, the environment and the planet all contribute to the One Health concept. 

Fascinating new research demonstrates that the pregnant mother’s microbiome shapes the child’s immune response as well. We did not discuss this with our guest, but you can read more about it here. 

Emeran Mayer, MD, is the executive director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience and the director of the UCLA Microbiome Center. The National Institutes of Health have supported his research for the past twenty-five years. Dr. Mayer is considered a pioneer and world leader in the area of brain-gut microbiome interactions. He wrote The Mind-Gut Connection: How the Hidden Conversation Within Our Bodies Impacts Our Mood, Our Choices, and Our Overall Health. Dr. Mayer’s new book is The Gut-Immune Connection: How Understanding the Connection Between Food and Immunity Can Help Us Regain Our Health. His website is https://emeranmayer.com/

Ken Pivak holds the copyright to the photograph of Dr. Mayer.

The podcast of this program will be available Monday, August 30, 2021, after broadcast on August 28. You can stream the show online from this site and download the podcast for free.