Researchers found that the gut microbiome – the bacteria that help digest food and absorb nutrients in the intestines – can influence attempts at weight loss.
They identified genes within these bacteria that determine how quickly the bacteria grow, how well people can take advantage of nutrients in food, and whether starches and fiber, in particular, get broken down into sugars too quickly to aid weight loss.
“Some people have a harder time losing weight than others,” study author Sean Gibbons, PhD, told this news organization. “For example, some people are able to control their weight through basic lifestyle interventions, while others may not.”
Furthermore, it is difficult to predict which individuals will respond to changes in diet or exercise and who might require more intense strategies.
The study, which was published online September 14 in mSystems, a journal of the American Society for Microbiology, could bring us closer to an answer.
“We’ve identified specific genetic signatures in the gut microbiome that were predictive of weight loss response in a small cohort of patients following a healthy lifestyle intervention,” explained Dr. Gibbons, Washington Research Foundation distinguished investigator and assistant professor at the Institute for Systems Biology in Seattle.
Weight loss takes guts?
Differences in 31 functional genes emerged from the gut microbiome in 48 people who lost 1% or more of their weight each month compared with 57 others whose weight remained the same. These findings came from stool samples taken 6 to 12 months after people started a commercial weight loss coaching program.
In contrast, lead author Christian Diener, PhD, also of the Institute for Systems Biology, and colleagues found only one factor in the blood that differed between the weight loss and weight maintenance groups. (They specifically evaluated proteins associated with obesity in the blood and genetic data from stool samples in a subset of 25 participants.)
Their findings align with previous research showing different types of bacteria in the gut microbiome can affect the success of weight loss interventions, but they took it a step further to determine how this works.
“We know that the gut microbiome plays an important role in weight management and can also influence a response to weight loss interventions. However, specific gut microbiome features that can explain this observation in more detail are still to be discovered,” Hana Kahleova, MD, PhD, MBA, director of clinical research at the Physicians Committee for Responsible Medicine in Washington, D.C., told this news organization when asked for comment.
Good versus bad players
On the plus side, genes that help bacteria grow more rapidly were associated with weight loss. These bacteria take more of the nutrients in food for themselves, leaving less to go toward human weight gain compared with slower growing bacteria.
In fact, prior evidence points to a particular gut bacteria, Prevotella, as being beneficial for weight loss. “In our study,” Dr. Gibbons said, “we found that some of the fastest-growing microbes in the weight-loss responder group were from the genus Prevotella.”
On the other hand, bacteria that produce more enzymes to breakdown starches or fiber quickly into sugars, for example, were linked with making people more resistant to weight loss.
“By understanding these functional patterns, we may one day be able to engineer resistant microbiomes to be more permissive to weight loss,” Dr. Gibbons said.
Dr. Kahleova agreed. “These findings expand our understanding of the specific features of the gut microbiome that play a role in weight loss,” she said.