Microbiome Bites November 27th: Mice provide insights on yo-yo dieting.
It looks like it’s going to be mostly animal studies this week, however these studies have some really exciting implications…
1. Gut Microbes Contribute to Recurrent “Yo-Yo” Obesity
After a successful diet many are often distressed to find their weight returns in what is often termed yo-yo obesity. The vast majority not only return to their original weight but also gain weight with each dieting cycle. In a study published in the journal Nature a team from the Weizman Institute of Science has shown in mice that the gut microbiome plays an unexpectedly important role in yo-yo obesity, and that this may be prevented or treated by altering the composition or function of the microbiome. The researchers found that after a cycle of gaining and losing weight, all the mice’s body systems fully reverted to normal – except the microbiome. For six months after losing weight, the mice retained an abnormal “obese” microbiome. Most interestingly, the team discovered that supplementing their drinking water with flavonoids stopped the post-diet mice from regaining the weight. If this research holds true in humans it could be a huge step forward in treating the obesity epidemic. Read the Weizman press release here. The study can be found here.
2. The gut microbiome affects host gene expression
Simply put, epigenetics describes things not encoded in DNA that influence gene expression. In a study comparing mice raised in a "germ free" environment and mice raised under more typical lab conditions, scientists have found that the gut microbiome mediates host gene expression through the epigenome, the chemical information that regulates which genes in cells are active. This regulation appears to be diet specific. A high-fiber plant based diet seems to favor host-microbe communication.
The most significant finding from the study was that supplementing the germ-free mice with short chain fatty acids (SCFAs) was enough to promote the kind of healthy interplay between microbiota and host cells seen in mice given a diet high in plant fiber.