An experiment with mice has revealed that brown rice reduces the desire for high-fat foods, a finding that could help prevent obesity and diabetes in humans, according to researchers.
The group, led by Prof. Hiroyuki Masuzaki of Ryukyu University, published the study in an academic journal of the American Diabetes Association.
Humans and other mammals tend to prefer fatty foods as they help stave off hunger.
The group gave mice a choice between diets of fatty food and normal food: a high-fat diet consisting of 45 per cent lipids, 35 per cent carbohydrates and 20 per cent proteins, and the other 10 per cent lipids, 70 per cent carbohydrates and 20 per cent protein. The mice chose the high-fat food every time and eventually became obese.
However, after the researchers replaced half of each diet's source of carbohydrates--corn starch and other substances--with brown rice, the mice opted for the normal food and as a result cut half their increased weight. When the team mixed white rice with the food instead of brown rice, the same phenomenon was not seen.
When the team extracted gamma oryzanol from the brown rice bran and gave it to the mice, they also chose the normal food, showing that the substance helped increase the mice's distaste of fatty food.
After mice ate the fatty food, stress was produced in the brain's hypothalamus, which controls appetite, and they craved more fatty food. The study revealed that eating brown rice was effective in controlling the stress.
As brown rice also inhibits the absorption of fat in the bowels, the concentration of sugar and neutral fat in the blood decreased.
The team plans to conduct experiments this autumn to confirm the effect, by having about 50 people take supplements of gamma-oryzanol, a major component of brown rice.
"Brown rice is a safe food and people have been eating it for ages. We'd like to develop nutritional supplements to prevent obesity and diabetes," Masuzaki said.