Tough to overcome obesity? The gut microbiome might to blame

The gut microbiome is widely viewed as potential target for novel therapeutics, and not just for its role in gastrointestinal conditions such as inflammatory bowel disease. Now scientists are providing fresh insights into how intestinal bacteria contribute to obesity.

Microbiologist Christoph Thaiss and his team at the University of Pennsylvania discovered that changes to the biological clock, coupled with a previous history of obesity, can disrupt the activity of the gut microbiome and increase susceptibility to obesity.

The findings, which were published in the journal Science, helped Thaiss win the 2018 Science & SciLifeLab Prize for Young Scientists.

For their study, Thaiss and his colleagues uncovered microorganisms in the digestive tracts of both mice and people that have a biological clock that ticks in a daily pattern. Any disruption of the regular cycle—either by genetic modification or an environmental factor like jet lag—can also change the microbiome’s rhythm. That triggers a cascade effect that makes mice and humans more prone to becoming obese, according to a press release.

Obese individuals who successfully lose weight often fail to keep the pounds off—a phenomenon known as the "yo-yo effect." Thaiss’ team found that a period of obesity changes the composition of mouse microbiomes for a long period of time, raising the risk of fast weight rebound.

That finding seemed to confirm a 2016 Nature study by Israeli scientists that suggested that the intestinal microbiome somehow retains an obesity "signature" that persists after successful dieting and contributes to faster weight relapse, even on a normal diet. Researchers in that study suggested that modulating flavonoids could hold potential as novel therapeutics for weight management.