Gut bacteria may determine weight
Gut bacteria may be able to "spread" obesity or thinness when transplanted in mice by changing the metabolism, according to a study published in the journal Science. For the study, gut bacteria from pairs of human twins, one lean and one obese, were transplanted to different sets of mice that lacked gut bacteria.
Researchers found that mice who received gut bacteria from an obese twin gained more weight and fat than those who received bacteria from a lean twin. In addition, the bacteria altered the metabolism of the mice. Those that received the gut bacteria from the obese twin showed an increased production of branched-chain amino acids, which have been linked with obesity in humans. The mice that received lean gut bacteria showed increased breakdown of carbohydrates, which is linked to weight loss. For the second part of the study, researchers housed the mice together to see if the gut bacteria would influence the other mice. After 10 days, they found that the mice with "obese" bacteria underwent metabolism changes that protect against obesity. This happened because the "lean" bacteria were being shared between the mice. But, when the mice were fed a diet high in fat and low in fiber, the obesity protection was not passed along.
Previous research has found that obese people have less diversity in their gut flora than lean people, and now research suggests that gut bacteria may protect against obesity, but it also depends on diet. Results of the study may offer new potential for probiotics that fight obesity.