Scientific studies now have established that oat bran deserves its popular reputation as a healthy food that can reduce blood cholesterol levels, according to a panel of biochemists and physicians.

The studies show that oat bran actually rivals the effectiveness of certain prescription drugs widely used to reduce high blood cholesterol, said Dr. James W. Anderson, an authority on dietary fiber with the University of Kentucky.Anderson said that oat bran may be more effective because it has none of the side effects of drug therapy. The side effects of anti-cholesterol drugs lead some patients to take only part of the prescribed dose, he explained.

"The traditional American Heart Association diet does not pack the wallop we'd like," he said, noting that the diet typically achieved a 5-7 percent reduction in blood cholesterol.

"When eaten consistently, oat bran can reduce blood cholesterol by 15 to 20 percent."

Authorities say that for every 1 point decrease in blood cholesterol, a person's risk of a heart attack decreases by 2 percent. Thus, when eaten consistently, oat bran can reduce heart attack risk by 30 to 40 percent.

High fiber diets also are associated with a reduced risk of cancer of the colon and other diseases, he noted.

Anderson was among a group of scientists who reported the latest research findings on oat bran and other dietary fiber at meetings of the American Chemical Society.

"Eat fiber," said Dr. David A. Jenkins, of the University of Toronto. "Buy your fiber from the grocery store and not the pharmacy."

Members of the panel agreed that whole grains, fruits and vegetables are the best sources of dietary fiber. Fiber consists of a complex assortment of indigestible material in food.

But they said the big challenge of the future will be in determining how fiber acts in the body to reduce blood cholesterol and the risk of cancer and other diseases.