Your Body Weight May be Caused by Heritable Gut Microbes

Could gut microbes be responsible for your weight? Scientists have studied pairs of twins and have found that a little known, heritable bacterial family is more common in individuals with low body weight; the findings could have implications for treating those suffering from obesity.

Previous research has linked both genetic variation and the composition of gut microbes to metabolic disease and obesity. Despite these shared effects, though, the relationship between human genetic variation and the diversity of gut microbes was thought to be negligible. This new study may show otherwise.

In order to learn a bit more about the role of gut microbes and genetics in obesity, the scientists sequences the genes of microbes found in more than 1,000 fecal samples from 416 pairs of twins. The researchers found that the abundances of specific types of microbes were more similar in identical twins than in non-identical twins.

What was more interesting, though, was that scientists found that a type of bacteria in a family called "Christensenellaceae" was heavily influenced by genetics. The scientists also discovered that members of this family of bacteria were more abundant in individuals with a low body weight than in obese individuals.

The researchers actually treated mice with members of this family of bacteria. The treated mice gained far less weight than untreated mice, which suggested that this microbe may actually help prevent or reduce obesity.

"Our findings show that specific groups of microbes living in our gut could be protective against obesity-and that their abundance is influenced by our genes," said Tim Spector, one of the researchers, in a news release. "The human microbiome represents an exciting new target for dietary changes and treatments aimed at combating obesity."

The findings are published in the journal Cell.