In our nationally syndicated radio show this week, we with an international expert about managing the microbiome. How does the microbiome interact with our immune system? Each of us has trillions of microbes living in our digestive tract. The exact number and type of species varies from one person to the next, so in essence our microbiome is as unique as our fingerprint. Unlike fingerprints, however, the microbiome is constantly changing. Our guest, Dr. Eran Elinav, considers the microbiome a neglected organ with a wealth of knowledge above and beyond that residing in our human genes.

You may imagine that the microbiome could affect your digestion–and it can. On the other hand, you might think that these microscopic entities would have little impact on our physiology, our joints or our brains. The microbiome can change our susceptibility to cancer and our response to chemotherapeutics. It has a profound effect on our immune system, which could turn out to be important during a pandemic. Scientists are now learning more about managing the microbiome through diet and medications.

Most scientists studying our microbiota rely on stool samples. It is by far the simplest way to get access to the inhabitants of our colons. However, Dr. Elinav and his colleagues have discovered that the microbes in stool are an incomplete representation of our full microbiome. They have done studies utilizing colonoscopies to take samples. Soon, Dr. Elinav envisions less invasive technology will become available for studying microbiota in the gastrointestinal tract itself.

One surprising discovery is that the balance of microbes is different from morning to evening. Since the digestive tract is not exposed to sunlight, how do the microbes manage these regular circadian rhythms? It seems that they take their cues from the meals that humans eat. Many nutrition experts recommend that we consume more foods rich in fiber to keep our microbiota healthy. Dr. Elinav suggest, however, that the interplay is more complex.

Keeping blood sugar under control is crucial for our overall health. For decades, experts have referred to the glycemic index, a way of measuring blood sugar response to different foods in comparison to a standard, such as white bread. Dr. Elinav and his colleagues have found, though, that even that so-called “standard” can elicit quite different blood sugar responses in different individuals (Cell Metabolism, June 6, 2017).  The differences in response depend primarily on differences in the gut microbiome. They suggest, “understanding dietary effects requires integration of person-specific factors.”

Dr. Elinav and his colleagues at the Weizmann Institute of Science have developed artificial intelligence algorithms that correctly identify how an individual will respond to certain foods. These algorithms can recommend diets that will help people control their blood sugar. But not everyone has access to these high-tech tools. With effort, a low-tech alternative can be useful. To do so, you would measure your blood sugar after eating with a glucose monitor like those used by people with diabetes. Keeping careful records will allow you to identify how you–with your specific microbiome–react to particular foods and which ones are least likely to raise blood sugar to unhealthy levels.

Managing the microbiome effectively will give us the opportunity to prevent a large number of chronic conditions. Our microbiome can help prevent intestinal permeability and its numerous consequences. In addition, interactions between the microbiota and our immune systems contribute to heart disease, diabetes, arthritis and even brain disorders such as ALS. Learning to maintain the health and balance of our microbes could help us avoid or possibly reverse such problems.

Eran Elinav, MD, PhD, is a professor of immunology and principal investigator at the Weizmann Institute of Science in Rehovot, Israel, where he co-directs the Personalized Nutrition Project. Dr. Elinav is also a principal investigator at the German Cancer Research Center in Heidelberg, Germany. His research focuses on understanding the complex interactions between humans and the bacteria that reside in their gut and how these interactions shape human health and disease. His labs at the Weizmann Institute and DKFZ focus on deciphering the molecular basis of host-microbiome interactions and their effects on health and disease, with a goal of personalizing medicine and nutrition. He is co-author, with Dr. Eran Segal, of The Personalized Diet.

You may be interested in his recent publications such as this one on the impact of the microbiome on weight gain following smoking cessation: Nature, Dec. 8, 2021

Here is an important article on probiotics following antibiotic use: Nature Microbiology, Aug. 2021

Dr. Elinav’s team has found that our microbiome may contribute to our aging process: Microorganisms, March 21, 2022

The podcast of this program will be available Monday, May 30, 2022, after broadcast on May 28. You can stream the show from this site and download the podcast for free.

Download the mp3