100 Trillion Friendly Germs: Some Might Control Your Weight

Somewhere among the 100 trillion friendly germs that make up your microbiome — the microbes that live in your body — we just might find the key to healthy weight regulation. Plenty of people are looking.

The role of the microbiome in obesity is a theme woven throughout a lengthy essay by Michael Pollan in the New York Times Magazine this weekend. It’s also the subject of numerous new scientific publications this week.

Brian Parks recently presented  insights from ongoing systematic studies at UCLA of the interactions between the genetics, diet, and microbiome of mice. This is a huge undertaking that is systematically documenting how a high-fat, high-sugar diet produces very consistent shifts in gut microbes, and how the diet interacts with the genetic makeup of the host. The work provides more evidence that food intake is not sufficient to explain obesity. His presentation was part of the UAB NORC Seminar Series.

A publication by Amandine Everard and colleagues this week in the Proceedings of the National Academy of Sciences demonstrated that feeding Akkermansia muciniphila bacteria to mice with obesity did much to reverse their condition. They responded with improvements in a range of metabolic disorders, including fat-mass gain, metabolic endotoxemia, adipose tissue inflammation, and insulin resistance. The authors conclude that their results provide a rationale for developing a treatment for obesity and related diseases that uses this bacterium.

Martin Blaser, a physician and microbiologist at NYU, calls H. pylori a “poster child” for endangered species of the microbiome. Blaser has identified a role for H. pylori in regulating appetite through the hormone ghrelin. He believes that the gradual extermination of H. pylori may be contributing to growing obesity prevalence.

Chronic inflammation is a mechanism for the harmful effects of obesity that our friendly germs might influence. In Adipocyte, Daniel Kemp reviews the basis for an emerging theory that chronic, low-grade entotoxemia may represent a causal factor in obesity-related inflammation, and that diet-induced changes in the gut microbiome may be a key regulator of metabolic health. He concludes that these mechanisms may point the way to new treatments for a wide range of acute and chronic diseases, including obesity.

Click here to read the Pollan essay in the New York Times, click here for the Parks seminar at the UAB NORC, click here to read the Everard study, click here to more about the role of H pylori, click here to read the Kemp publication, and click here to read more in Current Biology.

Cluster of E. Coli, image © Microbe World / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.