Gut Bacteria May Cause Obesity

Certain bacteria in the gut may affect appetite and inflammation, leading to obesity and bowel diseases such as Crohns disease, according to new research from Emory University School of Medicine, Atlanta (Science. 2010; March 4). Lead researcher and Emory professor Andrew Gewirtz said the study suggests harmful bacteria not regulated by beneficial bacteria which may be wipe out from antibiotic use or other dietary reasonsmay play a role in the overeating epidemic that faces modern society.

The study set out to investigate colitis in mice, but the researchers found germs may influence the development of colitis and similar inflammatory bowel diseases. They transferred mice embryos to surrogate mice mothers, as babies are colonized by bacteria and other mirco-organisms shortly after birth, usually with a microbiota profile similar to the mother. The transferred embryos escaped most of the colitis development after birth, but they developed obesity and metabolic syndrome, including insulin resistance.

They paired up with another research team which had previously found skinny mice fed gut bacteria from fat mice became obese. Limiting the food intake for such mice reduced weight gain and obesity, but insulin-resistance persisted. Gewirtz said the group thinks the mice are prone to gut inflammation due to the bacteria in their guts. They plan to look at what types of bacteria may be responsible for this association. They also plan to look investigate whether obese people have unique gut bacteria profiles.

The researchers turned to antibiotic therapy, which is mostly non-selective, to help kill off the offending bacteria, with no mention of probiotics, which can reduce bad bacteria levels, via competition, while preserving or boosting good bacteria levels.