Daily injections of a natural hormone found in the gut may help people lose weight by helping them feel full after eating less.

A new study showed that overweight and obese people who received injections of the hormone oxyntomodulin 30 minutes before each meal, three times a day lost an average of about five pounds over a four-week period -- even though they were told to maintain their regular diet and exercise levels.

The hormone oxyntomodulin is one of several hormones found in the gut thought to regulate appetite. In particular, oxyntomodulin is released after eating food and promotes a feeling of fullness.

Researchers say that by increasing levels of this hormone before meals, overweight and obese people may be able eat less while still feeling full.

If further studies confirm these results, which appear in the current issue of the journal Diabetes, researchers say use of oxyntomodulin may offer a new way to treat the growing worldwide epidemic of obesity.

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Hormone Helps People Eat Less and Lose Weight

In the study, researchers compared the effects of daily injections of the hormone on weight in a group of 26 overweight or obese men and women. Fourteen of the participants injected the hormone under the skin in the abdomen area 30 minutes before each meal, three times a day for four weeks. The rest of the participants acted as a comparison group and followed the same procedure using a placebo injection (saline solution).

All of the participants were asked to maintain their normal diet and exercise levels during the study.

After four weeks, the results showed that the people who used the hormone lost an average of about five pounds compared with an average of about one pound lost in the comparison group.

In addition, people who used oxyntomodulin also experienced a reduction in fat-related hormones that suggests a loss of fat deposits within the body. Leptin levels decreased; it is a hormone that is made predominately in fat cells. The amount of leptin in the blood is proportional to the amount body fat. It is known as one of the "hunger hormones."

The treatment group ate an average of 170 calories less at their first meal after receiving the hormone injection. By the last meal of the study, hormone users ate 250 calories less than the comparison group and reported no loss of food palatability.

Researchers say the weight loss was maintained during the entire four-week study period, but the participants in the treatment group gained back the weight within two weeks after the hormone injections stopped.

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By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCE: Wynne, K. Diabetes, August 2005; vol 54: pp 2390-2395.