Fat Distribution Controlled by Genetics
People become overweight in different ways. Some will develop a beer gut (apple-shaped) while some will have the fat go to their rear and thighs (pear-shaped). Two new major studies have identified a set of genes that determine where the fat goes in obese people. The team of international researchers also identified genes that determine individual susceptibility to obesity.
The researchers were led by scientists at Oxford University and the Medical Research Council (MRC) Epidemiology Unit in Cambridge. Their work reveals greater understanding into the biological processes that can lead to obesity and determine the body fat distribution. The work may eventually lead to new ways of preventing and treating obesity.
The location of fat storage on the body can have a great impact on individual health. For example, apple shaped obesity is associated with an increased risk of type 2 diabetes and heart disease. Conversely, some research suggests that pear-shaped obesity can actually help prevent diabetes and high blood pressure.
These health implications create a much greater significance for the waist-to-hip ratio. It is this ratio that the researchers have found to be determined by our DNA. There are 13 new gene regions linked to body fat distribution, seven of which have a much greater effect on women. This means that genetics underlie the difference in fat distribution between men and women.
The second study focused on genes that are associated with the body mass index (BMI), a commonly used measure to classify individuals as overweight or obese. Researchers have found that there are genes involved in the brain which influence our appetites and genes which control insulin levels and overall metabolism.
Test subjects who inherited more "BMI-increasing DNA variants" weighed 7-9 kg (15-20 lbs) more than subjects with less of these genes. However, the connection between these genes and obesity only explain 1.45% of the variation seen in people's BMIs. Therefore, there are still many more genetic associations to be found.
According to Dr. Ruth Loos, senior researcher who was involved with both studies, 'These two studies are the beginning of new insights into the biology of obesity and body shape, which in turn may lead to more targeted approaches to obesity prevention and potentially to the development of new drugs. But we should not forget that, while the genetic contribution to obesity is substantial, a large part of obesity susceptibility remains down to our lifestyle.'
The studies were carried out by an international collaboration of over 400 scientists from 280 research institutions. The results are published in the journal, Nature Genetics.
Link to published article: http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.685.html