The resulting composition of gut microbiota in the three gastric bypass patients differed substantially and in potentially important ways from obese and normal weight individuals. This means the drastic anatomical changes created by gastric bypass surgery appear to have profound effects on the microorganisms that inhabit the intestine. This change may be part of the reason that gastric-bypass surgery is the most effective means to treat obesity today.
The team's study is the first molecular survey of gut microbial diversity following surgical weight loss, and has helped solidify the link between methane producing microbes and obesity. Specifically, the microbial populations extracted from obese individuals were high in a particular microbial subgroup, hydrogen-producing bacteria known as prevotellaceae. Further, such hydrogen producers appear to coexist with hydrogen-consuming methanogens, found in abundance in obese patients, but absent in both normal weight and gastric bypass samples. Unlike the hydrogen producers, however, these methane-liberating hydrogen consumers are not bacteria. They belong instead to the third great microbial domainthe Archaea, (with Eukarya and Bacteria making up the other two).
During the course of digestion, calories are extracted from food and stored in fat tissue for later usea process delicately regulated by the multitude of microbial custodians. The intermediary products of the digestive process include hydrogen, carbon dioxide and several short chain fatty acids (SCFAs).
Results suggest a cooperative co-existence in obese individuals between hydrogen-producers and hydrogen consuming methanogens. Rittmann explains
|Contact: Joe Caspermeyer|
Arizona State University