In Cholesterol Wars, It’s a Bran New Day : Health: New findings on oat fiber stress the importance of the process involved in testing food products. And what happens when scientists, marketers and consumers collide.
You can hardly hear the crunch of toasted cereal over the guffawing as Americans react to the news that oat bran isn’t all it was cracked up to be as a factor in lowering cholesterol.
What would be more unfortunate than this national occasion for nutritional humor, though, would be if people use the oat bran debacle as an excuse to avoid taking responsibility for their own health habits.
It would also be unfortunate if the fuss creates a perception that science and its practitioners can’t be trusted.
How did we get into this fix that has made scientists look foolish, food marketers look greedy and consumers look confused?
Partly, it has arisen from the different goals and methods of the three groups.
Scientists work in a world where “truth” is a phenomenon whose boundaries change with each new discovery. Although they are disappointed when a favorite hypothesis proves faulty, scientists subscribe to a belief system that moves toward consensus slowly and often with much open disagreement.
Marketers seek to use information to the seller’s advantage and profit. Where a scientist--ideally--will be cautious about early implications of research, a marketer will turn them into advertising copy.
Consumers generally just want a breakfast, lunch or dinner that tastes good and is good for their health. But in today’s information age they get the minutiae of the scientific and marketing processes. Sometimes it seems as if a person needs either total ignorance or a Ph.D. to pick up knife and fork.
The priorities of these three groups collided dramatically in the instance of how diet can be manipulated to avoid atherosclerosis, the artery deposits that begin when there are too many cholesterol-rich molecules in the blood. Heart attacks and strokes, the major complications of atherosclerosis, kill more than 600,000 people every year.
Until last week, oat bran seemed like just the solution to unite science, advertisers and consumers in attacking this problem with food.
Then came the study published in the New England Journal of Medicine by researchers at Harvard University and Brigham and Women’s Hospital in Boston.
Using a time-tested method of pitting two similar foods against each other, it compared the effect on already-moderate blood cholesterol levels of fiber-rich oat bran and wheat from which virtually all the fiber was removed.
The result: Although oat bran’s fiber had been suggested in earlier studies as the source of a cholesterol-lowering effect, test subjects’ blood cholesterol levels were no different during six weeks of eating oat bran muffins and oat bran cereal than they were during six weeks of downing white-flour muffins and Cream of Wheat.
The moderate cholesterol readings in the 20 test subjects fell slightly, about 7%, on both diets. The authors concluded this was simply because someone who eats enough whole or refined grains for breakfast, be it as oat bran or Cream of Wheat, has no room for bacon and eggs or a croissant too--and it is fat-rich foods like those (and their excess calories) that kick the liver’s cholesterol-producing machinery into high gear.
The differences between the results of the current study and earlier ones can be explained at least partly by differences in study design that are inherent in the process of science.
In any field, the earliest studies use a broad brush-stroke approach--looking for effects where they are most likely to be found. Each successive study narrows the questions and gives more precise answers about what mechanism is at work.
And results that might appear contradictory are often merely different perspectives on the same question.
In the case of oat bran, research in the early 1980s focused on men with hypercholesterolemia, or extremely high levels of cholesterol in their blood. The study did not have a “control diet” of other grains: Some of the men ate oat bran, and some didn’t, and cholesterol-lowering effects of up to 19% were found. But, as the research questions were narrowed, the effects of adding oat bran became smaller or nonexistent.
Last week’s study changed the ground rules somewhat.
First, subjects were more “normal” than earlier subjects had been. They had average blood cholesterol readings of about 180 milligrams per deciliter of blood, 60 milligrams below the level at which a person is considered in serious trouble.
Furthermore, the study tried to isolate the effect of adding carbohydrates to the diet as opposed to fiber.
And--importantly--it corrected individual differences in diet that might skew the results by doing a “double-blind crossover.” Test subjects first ate one grain supplement for six weeks, but weren’t told what it was, and then later they ate the other grain.
The early studies’ effects on hypercholesterolemics were dramatic enough to send marketers scrambling to lure customers from among the millions of middle-aged Americans with borderline-high levels of blood cholesterol.
These weren’t the same people tested in those early studies, but they are the ones most likely to be addressing their problem through diet rather than drugs.
In perhaps the most poorly timed jump onto the bandwagon, researchers at Louisiana State University issued a press release nine days before the New England Journal article saying they had found that “rice bran is as effective in reducing cholesterol levels as oat bran.”
Indirectly, this study--still not published in a scientific journal--confirms the Boston study’s hypothesis that grains’ effects on cholesterol are the result of lower fat intake.
Total cholesterol fell about 7%, the same as in Boston, on oat bran and rice bran diets. But rice bran has very little of the gooey soluble fiber that some have suggested is the mechanism by which oat bran lowered blood cholesterol in early studies.
Thus, Americans have been bombarded with oat bran products even though it wasn’t until last week that the first study was published on whether oat bran would really affect heart disease risk factors for most of them.
As a practical matter, even if oat bran does prove to lower cholesterol in some people, it will never be easy to achieve the intakes that are provided in research studies.
In a single day, one would have to eat eight bowls of one common oat bran cereal to reach the 100 grams of oat bran taken in by study subjects daily. If one opted for oatmeal, it would take about five 2/3-cup servings daily.
Aware of the difficulties consumers have in figuring out just what to eat, the American Heart Assn. Monday is launching the first stage of a nutrition rating program called HeartGuide.
More than 100 types of margarines, oils, shortenings, crackers, prepared vegetables and frozen entrees will be given the HeartGuide labeling seal, said Dr. Rodman D. Starke, senior vice president for scientific affairs at the association.
The products will be evaluated based on contents of total fat, saturated fat, salt and cholesterol--the only dietary elements that the association recognizes as undisputedly contributing to cardiovascular disease.
The oat bran/fiber effect on atherosclerosis is so uncertain that the association is unlikely to include oat bran or fiber content as a basis for determining “heart healthiness” when cereals are rated next summer, Starke said.
However, HeartGuide will have veto power over labeling and advertising of products it rates. It will use the power to prevent marketers from promoting characteristics of foods as heart-healthy where there is inadequate scientific evidence to support the claims, Starke said.
“The problem is that the food product companies have capitalized on the intensity of the interest in the American public in proper dietary choices and have provided the public with either partial information or misinformation,” said Dr. Myron L. Weisfeldt, a Johns Hopkin University cardiologist and president of the heart association.
Weisfeldt and other scientists still point out that the oat bran research so far does not mean definitively that oat bran has no effect on health. The studies that show soluble fiber in oat bran and beans lowering blood cholesterol in hypercholesterolemics still stand, for the moment.
And there is reason to believe that fiber in the diet is important for other health reasons.
A substantial amount of research indicates--although not conclusively--that fiber from vegetables as well as from grains appears to lower the risk of colon cancer and gastrointestinal ailments such as diverticulitis.
In addition, a diet high in the complex carbohydrates that are in grains and vegetables will by definition have less fat in it, and a lower-fat diet is associated with lower obesity, heart disease, cancer and other health problems.
The natural-foods aficionados who were still buying oat bran last week in Los Angeles stores seemed to have successfully navigated the murky oat bran waters.
“My philosophy is that if you eat something as close to its natural state as possible, probably you will be healthy enough that you don’t have to run out and buy a ton of oat bran,” Monica O’Connor of Mar Vista said as she shopped at Mrs. Gooch’s Natural Food Store in West Los Angeles.
Erna Cooper of Westwood sounded like a National Research Council report as she browsed through Erewhon Natural Foods store in the Fairfax area: “Health food nuts go to the extreme with whatever fad is prevalent. I think it (oat bran) is very trendy, unfortunately.
“I don’t believe in taking anything to the extreme. A little moderation is pretty good. No one food element taken to an extreme is a cure for years of poor health or poor eating.”
Times staff writer Gary Libman contributed to this story.
