| Scientist - News - 21-04-2008: Increasing evidence for link between gut flora and obesity Beintema, Nienke Obese people and lean people differ significantly in the composition of their gut flora. Scientists are trying to find out whether these differences are the cause or the result of obesity. Recent evidence suggests the former. The trillions of bacteria in our digestive tract play an important role in regulating our body weight. These bacteria, among other things, help us to extract calories from our food. ‘Sterile mice’ – mice that were raised in a sterile environment and that possess no gut flora – are therefore much leaner than their ‘normal’ conspecifics. Furthermore, if you provide these sterile mice with a gut flora at a later age, they will gain more weight if that gut flora came from an obese mouse than if it came from a lean one. Apparently, a ‘lean’ gut flora is different from an ‘obese’ one. This has been observed in humans as well. Researchers from Washington University in Missouri reported this in Nature in 2006. Cause or effect? Scientists are still speculating as to whether a different gut flora is the cause or the result of obesity. They hope to find out whether manipulating the gut flora, for instance through the consumption of certain combinations of probiotics, could help people lose weight. A recent publication by a Finnish research group suggests that differences in the composition of the gut flora precede weight differences – rather than the other way around. The researchers collected faecal samples of children at ages 6 and 12 months, and followed these children until they were 7 years old. They found that early differences in the children’s gut flora were reflected in their weight at age 7. Obese 7-year-olds had displayed lower numbers of bifidobacteria and higher numbers of Staphylococcus aureus when they were babies. The researchers conclude that these early differences may be a predictor of obesity. Dr. John DiBaise from the Mayo Clinic in Minnesota recently published an overview of all relevant research outcomes to date. The Mayo Clinic itself is analysing gut microbiota in normal-weight and obese people, and in obese people following gastric bypass surgery. "Much more research is needed to clarify a number of issues related to the relationship between the gut microbiota and obesity," he states by email. "Future studies need to establish whether the small changes in caloric extraction seen in recent animal studies can produce measurable weight differences in humans. And above all, we need to be much more certain about the cause-effect relationships." DiBaise expresses optimism about the potential development of obesity treatments based on the manipulation of the gut flora. However, he underlines that this process may take many years. "I suspect that as our knowledge of the functions of individual species of probiotic micro-organisms improves," he says, "the current approach of bombarding our digestive tract with millions of one or more species of probiotics will change to an approach of tailoring the probiotic agent to the condition, much like conventional pharmacological therapy." For more information: www.eurekalert.org www.mayoclinicproceedings.com «Back |