Could a person's beer belly and thunder thighs have something to do with bacteria in their stomach?
Researchers noticed that when they gave a group of "germ-free" mice bacteria from an obese person's gut, they gained more wight than those who had received "thin-people-germs," an American Association for the Advancement of Science press release reported.
The researchers believe this finding is a step towards "developing new personalized probiotic and food-based therapies for the treatment or prevention of obesity," according to the press release.
The findings support the past study results that suggest more bacteria diversity in the stomach can lead to a leaner body. Eating more fruits and vegetables usually promotes a wider variety of bacteria.
This study marks the first direct evidence that gut bacteria can effect both obese and lean traits. It also begins to touch on the specific roles each type of bacteria plays. Bacteroides were found to prevent the accumulation of fat, for example.
Vanessa Ridaura, a graduate student at Washington University's School of Medicine, along with a research team, took bacteria samples from twins. One individual was obese and the other twin was lean in most cases. The team then transplanted bacteria from both twins' stomachs into the germ-free mice.
"The first thing that Vanessa identified in these mice, which were consuming a standard mouse diet, was that the recipients of the obese twins' microbiota gained more fat than the recipients of the lean twins' microbiota," Jeffrey Gordon, director for the Center of Genome Sciences and Systems Biology at Washington University School of Medicine and a co-author of the Sciencereport, said. "This wasn't attributable to diffences in the amount of food they consumed, so there was something in the microbiota that was able to transmit this trait. Our question became: What were the components responsible?"
The team tried housing mice from each group in the same cages, the rodents often swap bacteria by eating feces and other activities.
The researchers found the lean bacteria mice (Ln) and obese bacteria mice (Ob) that had been kept in the same cage all adopted leaner qualities. The Ln bacteria prevented accumulation of fat to an extent in all of the affected mice.
The Ln bacteria was able to "invade" the bodies of the Ob mice and change their metabolism, but the Ob bacteria wasn't able to get into the Ln mice.
"So, why isn't there an epidemic of leanness in America?" Gordon said.
Researchers also tried feeding the mice an exceptionally healthy diet (high fiber/low fat) and an unhealthy one.
The mice on the healthy diet did not exhibit much of a change, but the gut bacteria in the Ln mice on the unhealthy diet could not protect them from an increased body mass.
"We now have a way of identifying such interactions, dependent on diet, and thinking about what features of our unhealthy diets we could transform in ways that would encourage bacteria to establish themselves in our guts, and do the jobs needed to improve our well-being,"Gordon said. "In the future, the nutritional value and the effects of food will involve significant consideration of our microbiota-and developing healthy, nutritious foods will be done from the inside-out, not just the outside-in."
