Experts Divided Over the Benefits of Oat Bran : Cholesterol: Conflicting scientific data mean that the controversy may be with us a while.

Consumers could have a hard time sifting through the mushy confusion of the oat bran controversy that erupted last week when the New England Journal of Medicine reported that a Harvard University study had all but debunked former scientific conclusions of oat bran’s cholesterol-lowering effect.

For the American Heart Assn., it is not so much a question of oats and oat bran as it is a concern about fat in the diet. Other health authorities see the problem as one of overall dietary management.

In light of conflicting scientific data and disagreement among scientists themselves, relief from confusion over the oat bran controversy may not be immediate. But here are comments from health experts that may provide a better perspective on the issue.

“The effectiveness of a diet that lowers plasma cholesterol and consequently of reducing one of the risks of heart attack and stroke, is dependent upon proper choice of foods relative to fat and cholesterol content. A basic principle is that food products from sea and land animal sources contain cholesterol. Cholesterol is not found in any plant sources. The average person should limit their fat intake to less than 30% of their total calories.”

--Policy statement from the American Heart Assn.

“We ‘re confident in the science that relates to grains being an important part of the diet, and that includes research on both soluble and insoluble fiber. We believe in the research that says that a diet high in fiber and low in fat can reduce the risks of chronic diseases. Since oat bran is a good source of soluble fiber, the extensive data available continues to support benefits of this type of fiber. A diet low in fat and high fiber is recommended by numerous health organizations, and ready to eat cereals can easily be part of the diet.

“We don’t make claims that oat bran reduces cholesterol levels. We do, however, point out that oat bran can be part of the low fat high fiber diet that we were talking about.”

--Nancy Roach, manager of corporate publicity, Kellogg Co.

“The study that was done on oat bran (Harvard University study) was not definitive on the basis that the subjects had unusually low cholesterol levels for the population of this country to begin with. When you run a study measuring metabolic end point and start with a desirable end point, it’s hard to show improvement.

“People who have cholesterol levels higher than acceptable as far as risk factors go, have been shown to benefit when their diet includes fiber that can be solubilized in the intestine. Under these conditions, you’ll find that pectin, guar gum and, in some studies, oat bran, have properties that have been shown to lower cholesterol levels, especially in people with elevated cholesterol levels. I know it’s disturbing in nutritional studies to find inconsistencies, but they do occur. That’s why it’s necessary to look at the conditions under which the studies were done. You have to look at the population, the diet itself--was it already low in cholesterol?--and many other factors.”

--Dr. Sheldon Reiser, research leader of Carbohydrate Nutrition Laboratory, Beltsville Human Nutrition Research Center, United States Department of Agriculture

“The bottom line is that we should be focusing on lowering saturated fat in the diet. There are many other foods besides oat bran that have also shown cholesterol-lowering effects. There are lots of studies that show that foods high in soluble fiber do lower cholesterol. Americans still need more fiber in the diet, but it doesn’t have to come from one source only. Beans, legumes, peas, fruits, vegetables, carrots, broccoli are excellent sources of good fiber of the type that lowers cholesterol.

--Evelyn Tribole R.D., American Dietetic Assn. spokesperson

“We should keep in mind that an increase in dietary fiber, especially from grains, has been demonstrated, without question, to be helpful in gastrointestinal functions. There is also preliminary evidence that a diet higher in water soluble fibers, when substituted for fats, are associated with lower risk of colon cancer. The public should not think that by sprinkling oats on muffins that are high in fat it is going to help. The primary goal should be to reduce saturated fat and dietary cholesterol even if it means a major change in the diet.”

--William L. Haskell Ph.D., associate professor of medicine, Stanford University

“I have not read the paper in the New England Journal of Medicine, but have heard the reviews. I concur with the information that there has been a hype over what a specific bran might or might not do. Soluble fibers can be important in lowering blood cholesterol, but large amounts have to be consumed to have a significant effect. And I think those concerned with overall diet and health should not look to a single food or a single kind of food as a remedy. Instead they should follow the dietary principles we have all been told do work--and that is to eat a varied diet. People think it is boring because it is so practical, but it makes very good sense for the population as a whole. If, however, you have to follow a therapeutic diet, a few oat bran muffins is not going to do the trick.”

--Helene Swenerton Ph.D., nutritionist, Cooperative Extention, UC Davis Department of Nutrition

“I am in disagreement with the conclusion (Harvard University study reported in New England Journal of Medicine). In addition to the study design factors, the fat intake was not carefully controlled. This in itself makes it difficult to interpret. . . .

“Since the University of Kentucky’s first scientific article in 1981 showing the cholesterol-lowering effects of oat bran, seven additional published studies and three unpublished studies have documented the statistically significant cholesterol-lowering effect of oat bran. . . . An important factor to consider is that the new study included dietitians and hospital employees of Brigham & Women’s Hospital who would be more likely to have an enhanced awareness of changes in their diet. While it was a placebo controlled study, 18 of 20 subjects recognized when they were on a high fiber supplement as opposed to a low-fiber supplement. This, in itself, indicated that the study was not successfully blinded. In addition, it is important to consider the fat intake during the Harvard study. Caloric intake during the oat bran period consisted of 35.4% fat. This was significantly higher than the fat intake during the low fiber period, which was 30%. In other words, when research subjects were on the oat bran they increased their fat intake by 18%. That is a large increase.”

--James W. Anderson M.D., Metabolic Research Group, University of Kentucky Medical Center

“If you eat oat bran and still take in butter, cream and other fats, it won’t do the trick to lower cholesterol. You can get good soluble fiber and cut down on total fat and calories with foods other than just oat bran. If you eat a diet high in fiber, especially soluble fiber, such as oat bran and other good soluble fiber foods, but also reduce fat and cholesterol, and include some form of exercise in your daily regimen, that would make sense. Unfortunately people like to hang on to a panacea. There are no magic cures.”

--Dr. Genevieve Ho, nutritionist, UC Agricultural Extension Service, Los Angeles.