How gut bacteria could influence obesity susceptibility
The microorganisms we host in our bodies could have significant consequences for the onset of obesity, an EU-funded project has found. This discovery could change how the medical profession treats the disease, which is forecast to affect more than 700 million adults globally by 2015. Most importantly, it could provide doctors with a simple identification test to find people most at risk. The project, called METAHIT (Metagenomics of the Human Intestinal Tract), found that individuals with low gut bacteria richness were at greater risk of developing obesity-linked disorders such as type II diabetes and atherosclerosis. While the causes of obesity are partly due to external factors - sedentary lifestyle, easily obtained high energy food - it has also been broadly accepted that genetic factors also play a part. However, genetics has appeared to account for only a minor part of the obesity trend. This is why scientists have questioned whether variations in the microbiome - the global genome of all microorganisms we host in our bodies - could also have an impact on the onset of obesity than variations in the human genome. In order to find out, the METAHIT project focused on a cohort of 292 Danish adults, comprising 123 non-obese and 169 obese. The scientists analysed their gut bacterial composition with the help of a new analytical approach called quantitative metagenomics. They discovered that the cohort could be divided into those with an abundance of certain bacterial species, and those without. This distinction was not based on corpulence - lean and obese were found in both groups - even though 80% of the low bacterial richness group was obese. What was interesting to the scientists was that poor microbiota contained a higher proportion of pro-inflammatory and a lower proportion of anti-inflammatory bacterial species than the rich one. The team then discovered that people with poor microbiota had more body fat, were more resistant to insulin and displayed symptoms that put them at increased risk of contracting type II diabetes and cardiovascular disorders. Furthermore, obese people from the poor group gained more weight over time than the lean ones. These individuals either lacked entirely or had a very low abundance of eight particular bacterial species, which might therefore have a protective role against weight gain. Their discovery could lead to the development of new bacteria-therapies which help fight against weight gain. Preliminary findings of the METAHIT project have now been published, which should contribute to a better understanding of why some individuals appear to be more susceptible to obesity than others. The study should also help the medical profession to identify those at risk early, and develop appropriate preventative strategies. The METAHIT project, which consisted of 13 partners from a total of eight countries, received 11.4 million in EU funding. The project was completed at the end of June 2012.For more information, please visit: METAHIT http://www.metahit.eu/ Project Factsheet INRA
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