Two tablespoons of rice bran oil a day may cut harmful cholesterol levels by 30 percent and help keep arteries from getting clogged, experiments with monkeys suggest.

The oil can also raise so-called good cholesterol, which helps prevent heart disease, said biochemist Robert Nicolosi, director of the division of cardiovascular research at the University of Lowell in Massachusetts.Rice bran oil is widely used in Japan and available in some U.S. stores.

Nicolosi cautioned against a run on the oil like the one that followed preliminary findings that oat bran could lower cholesterol.

"Don't come away with the idea that rice bran oil is a magic bullet," Nicolosi said Monday at the annual science writers' meeting of the American Heart Association.

Nevertheless, he said, rice bran oil - which is colorless and tasteless and can be used on salads and in cooking - appears to have benefits that other foods don't.

Rice bran oil may be unique in lowering low-density lipoprotein, the bad cholesterol, without lowering high-density lipoprotein, the good cholesterol that helps remove the bad stuff from the bloodstream, Nicolosi said.

Nicolosi fed a group of monkeys a healthy diet containing rice bran oil. Another group got the monkey equivalent of a typical American diet containing more fat than nutritionists recommend.

Depending upon the amount of rice bran oil the monkeys consumed, Nicolosi found drops of 20 percent to 30 percent in their harmful LDL cholesterol. In some cases he found a slight increase in HDL.

If rice bran oil turns out to have the same effect in humans, people would need to consume less than two tablespoons a day to get the benefits.