Giving obese people top-ups of a naturally occurring gut hormone could help fight obesity, suggests a new study.
The research revealed that obese people have a third less of the hunger-beating hormone PYY3-36 in their blood than their leaner contemporaries. And giving both obese and slim people infusions of the hormone cut their appetites by about a third when offered an eat-as-much-as-you-like buffet, says the team from Imperial College London and the Hammersmith Hospital, also in London, UK.
鈥淭he discovery that obese people have lower levels of PYY3-36, an important factor limiting appetite, suggests a possible new treatment for the millions suffering from obesity,鈥� says Steve Bloom, a member of the team at Imperial. 鈥淭hese new findings suggest boosting PYY3-36 offers a novel approach towards treating the epidemic of obesity in our society.鈥�
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鈥淥besity is a global epidemic that is getting worse,鈥� warns Rachel Batterham, another team member, now at University College London. 鈥淪eventeen percent of children in the UK are obese. In the US, obesity accounts for 280,000 deaths a year. At the current rates of increase, it will pass smoking as the main cause of preventable death.鈥�
Eleanor Kennedy, research director of Diabetes UK, says: 鈥淎lthough this study is small the results are very interesting. Anything which helps obese people regulate their appetite could potentially reduce the number of people developing Type 2 diabetes.鈥�
Appetite buster
PYY3-36 is a hormone produced in the gut in response to eating. It acts on a part of the brain called the hypothalamus in a similar way to another appetite-busting hormone, leptin.
Leptin had once been hailed as a 鈥渨onder cure for obesity鈥�, Bloom told 快猫短视频. However, obese people were found to be resistant to its actions.
The team showed in 2002 that PYY3-36 could curb hunger by about a third in slim people. 鈥淲hen we found PYY inhibited appetite we thought we ought to test it in the obese,鈥� says Bloom. 鈥淲e found it worked, every bit as well as in the thin.鈥�
Twelve obese and 12 lean volunteers were given a 90-minute infusion of either the appetite-suppressing hormone or plain saline after an overnight fast.
People were markedly less peckish when given the hormone and offered an unlimited buffet lunch two hours later, compared with when they were given the saline placebo. Calorie intake was decreased by about 30 per cent in both obese and slim volunteers given PYY3-36.
Drinking beer
鈥淎nd we found something else,鈥� Bloom says. 鈥淥bese people had low levels of PYY 鈥� about 30 per cent lower. This means they don鈥檛 switch off their appetite after a meal properly. It鈥檚 no wonder they stay fat.鈥�
He adds: 鈥淧erhaps PYY administration would be a particularly effective treatment since the overweight are actually short of it.鈥�
However, Batterham cautions that if PYY does pass clinical trials 鈥渋t will not be a wonder treatment鈥� which will allow people 鈥渢o continue eating high fat foods and drinking beer鈥�. The hormone would only be effective when combined with lifestyle changes.
Journal reference: New England Journal of Medicine: (vol 349, p 935)