An appetite-curbing hormone found in the gut may help overweight and obese people shed weight, lower blood pressure and reduce cholesterol levels, according to a study.
Known as glucagon-like peptide-1, or GLP-1, the hormone is naturally secreted from the intestine when we eat.
Recently, doctors have begun to use GLP-1 to treat patients with type 2 diabetes due to the molecule's ability to regulate sugar levels in the blood.
But they also noticed that the hormone appeared to make patients less hungry, raising the question of whether it could work as a treatment for obesity.
A team of researchers led by Tina Vilsboll of the University of Copenhagen designed a study to find out.
Reviewing medical literature, they analysed the results of 25 clinical trials involving over 6,000 patients who had been given GLP-1.
Patients with and without diabetes who received a minimum dosage for at least 20 weeks showed greater weight loss than control groups, they reported in the British Medical Journal (BMJ).
There was also improvement in blood pressure, cholesterol and glycaemic control, the process by which the body adjusts the impact of carbohydrates on blood sugar levels.
The findings provide "convincing evidence" that GLP-1 "results in clinically relevant beneficial effects on body weight" for obese patients, the researchers concluded.
"Additional beneficial effects on blood pressure and total cholesterol might also be achieved."
The treatment had side-effects in some patients, including vomiting, nausea and diarrhoea. But this did not seems to effect the number of people dropping out of the trials, suggesting that, overall, GLP-1 was well tolerated, they said.
Vilsboll and colleagues recommended that the hormone be "considered" for obese patients suffering from diabetes, and called for further trials to test its efficacy for obese people who are not diabetic.
In a commentary, also in the BMJ, Raj Padwal from the University of Alberta argued that -- despite its weight-reducing powers -- GLP-1 should not alter current medical practice.
"Modification of diet and lifestyle remain the cornerstone of the treatment of type 2 diabetes," he said.
The hormone's longterm safety is still unknown, he added.