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| Key brain regions that regulate eating, reward and motivation show altered response to the hunger hormone ghrelin in subjects with the obesity-risk FTO variant.--Courtesy of University College London |
Scientists think they've solved the mystery of how a gene linked to obesity causes people to gain weight. The findings could pave the way for new therapies for the disease, which is a growing health concern around the world.
A research team at University College London conducted tests to determine how variations in the FTO gene--which occur in about one out of 6 people--make people 70% more likely to become obese. The gene has long been linked to obesity, but until now scientists did not know how it worked.
"Despite the need for further mechanistic studies, our current findings may have immediate implications for both the investigation of the neurobiological basis of human obesity and for its treatment," the researchers say in their paper, which was published July 15 in the Journal of Clinical Investigation.
The researchers found that having a variant of the FTO gene leads to high levels of ghrelin, a hormone involved in regulating hunger and how the body responds to food. Brain imaging revealed that the FTO gene variation also changes the way the brain responds to images of food. The study explains why some people with the FTO gene don't feel full after eating, triggering them to eat more and gain weight. The research also suggests that people with a variant of the FTO gene prefer higher calorie foods than those without the variation.
"At a therapeutic level this arms us with some important new insights to help in the fight against the obesity pandemic. For example, we know that ghrelin (and therefore hunger) can be reduced by exercise like running and cycling, or by eating a high-protein diet. There are also some drugs in the pipeline that suppress ghrelin, which might be particularly effective if they are targeted to patients with the obesity-risk variant of the FTO gene," said Dr. Rachel Batterham from UCL and University College London Hospitals, who led the study, in a university press release.
Previous FTO studies have relied on mice, but this study analyzed blood samples and brain images from people and found that those with the gene variation had higher levels of ghrelin in their blood as well as increased sensitivity to the chemical in their brains.
- read the press release
- here's the study