Scientists believe they may have found something to combat obesity and it may also help prevent the onset of diabetes.

The find, an edible seaweed containing the carotenoid fucoxanthin, when fed to rats enabled them to shed 10% of their body weight, mainly from around the gut.

Fucoxanthin is found at high levels in several different types of brown seaweed but not in green and red seaweeds and is tightly bound to proteins in the seaweed and not easily absorbed in its natural form.

Brown seaweed, also known as wakame, is a key ingredient in Japanese miso soup but the researchers say drinking large quantities of the soup in an effort to lose weight would have little effect.

The researchers from Hokkaido University hope that fucoxanthin can be developed into a slimming supplement or a drug that targets harmful fat.

Lead researcher Dr. Kazuo Miyashita, says it might be another three to five years before a slimming pill based on fucoxanthin was available to the public.

Dr. Miyashita’s team studied the effects of fucoxanthin on more than 200 rats and mice and found it was effective in fighting flab in two ways; in obese animals, the compound appeared to stimulate a protein called UCP1 which causes fat to be broken down; and the pigment also caused the liver to produce a compound called docosahexaenoic acid (DHA), which can help cut levels of “bad” cholesterol associated with obesity and heart disease.

The protein UCP1 is found in the white fat adipose tissue, which is responsible for “middle-age spread” and excess amounts of fat around the midriff are particularly linked to heart disease and diabetes.

No adverse side effects were seen in the animals used in the study but experts caution that medication, however good, is not enough and only a significant change in lifestyle will ever achieve long-term weight loss.

Previous studies by Miyashita’s team have shown that fucoxanthin also helps promote the death of human prostate cancer cells in the lab.

Their findings suggest that fucoxanthin has potential as a preventive agent for a variety of diseases.

The research was presented to an American Chemical Society meeting in San Francisco.