Link found between obesity, gut bacteria and genes

18 June 2010

Researchers at the University of Maryland School of Medicine have found a link between obesity, a variant of the FTO gene and the presence of certain bacterial groups in the digestive tract.

“Work currently under way suggests that an interaction between genetic factors and the composition of the bacteria that inhabit the human gut may predispose certain individuals toward obesity,” said Margaret Zupancic, PhD, a research fellow with the Institute for Genome Sciences at the School, who presented one of the studies.

"These results potentially provide insight into the mechanisms by which genetics may predispose some people to obesity. They could also help pave the way toward a future in which genetic screening in conjunction with individually tailored treatments could help people at risk for obesity to maintain a healthy weight."

Zupancic and her colleagues analyzed the gut bacterial communities of lean and obese individuals in the Old Order Amish of Lancaster County, Pennsylvania, which has a relatively homogenous population in regard to both genetics and lifestyle. Initially the researchers found no correlation between the composition of the gut bacteria and obesity, but when they factored in the genetic makeup of the participants, certain patterns began to emerge.

One pattern was a statistically significant correlation between whether the participant carried a given variant of a gene called FTO associated with obesity and the presence of certain bacterial groups in the digestive tract.

The researchers also found that in people with certain genetic variations in taste receptor genes, a low level of bacterial diversity in the gut correlated with a higher likelihood of obesity, while a high level of bacterial diversity correlated with a lower likelihood of obesity.

“While this work is still at a relatively early stage, results such as these could lead to applications such as probiotic [stimulate beneficial bacteria] or antibiotic-based treatments for obesity that could be individualized based on a person’s unique genetic and gut microbial makeup,” says Zupancic.