Hormone found to reduce appetite by a third

An international team of scientists has discovered a hormone that can significantly decrease the appetite, reducing the amount of food eaten in a day by a third.

The research, published today in Nature, shows how scientists from Imperial College London, with assistance from Oregon Health and Sciences University, USA, and the Garvan Institute of Medical Research, Australia, discovered the novel action of hormone PYY3-36.

PYY3-36 is normally released from the gastro-intestinal tract after eating, in proportion to calorific meal content, telling the brain the body is no longer hungry. When a group of volunteers received artificial infusions of the hormone at normal post-feeding concentrations, their food intake was reduced by a third for a day.

Professor Stephen Bloom, from Imperial College London at the Hammersmith Hospital, comments: “The discovery that PYY3-36 suppresses appetite could be of huge benefit to those struggling with weight problems. With over a billion people across the world now extremely overweight, it is vital this problem is tackled.

“It may be possible to identify foods which cause the release of more PYY3-36, helping to naturally limit appetite, or it may be possible to create a tablet with a similar effect, providing an excellent, natural and safe long term treatment for obesity.”

The research was undertaken as part of an ongoing programme at Imperial, looking into how human drives work, of which appetite is an important example.

To test if PYY3-36 is effective, twelve volunteers were infused with either PYY3-36 or saline for ninety minutes in a double blind randomised crossover trial at Hammersmith Hospital, London. Two hours later, the volunteers were offered an unlimited buffet meal.

In the group receiving PYY3-36, average calorific intake dropped by a third over the next 24 hours.

The researchers also looked at how hungry the test group felt both during and after transfusions of the hormone. The group receiving PYY3-36 reported up to a forty percent drop in perceived levels of hunger over a period of twelve hours after infusion.

Dr Rachel Batterham, from Imperial College London at the Hammersmith Hospital, adds: “The results show the hormone PYY3-36 could help in tackling the problem of obesity. Rather than using extreme measures such as dieting pills, or even surgery, PYY3-36 should be able to provide a far safer and effective alternative.”