Knowing your oats about the fiber-cholesterol connection.
Millions of Americans have jumped on the "bran wagon."
For nearly two years, America has been experiencing oat bran mania, ignited by research showing that the soluble fiber contained in oats can play a role in reducing blood cholesterol, thereby decreasing the risk of heart attacks.
So the humble oat has come into its own, and not just in the conventional hot oatmeal breakfast. We now have oat bran muffins, bagels, breads, cereals, brownies, fruit bars, granola and even a contradiction more curious than most - oat bran-fortified potato chips.
Meanwhile, amid the oat bran hype, confusion reigns among the public. So what are the facts according to the best scientific evidence?
Some studies have reported that large doses of soluble fibers - such as those present in oat products and beans - have reduced blood cholesterol levels as much as five to 15 percent. But authorities interviewed by Arthritis Today say the impact of soluble fiber is actually much less than a 15 percent reduction
"Soluble fibers may give about a three to five percent reduction in blood cholesterol level," says Dr. Margo Denke, a physician specializing in nutrition and lipids (fats) research at the University of Texas Southwestern Medical Center at Dallas.
Nancy Ernst, R.D., nutrition coordinator for the National Heart, Lung and Blood Institute, agrees. She says reports summarizing studies of oat bran's effects on cholesterol levels don't specify which studies were well controlled in their research design. "Of all the studies, some did show as much as a 15 percent reduction," she says. "But many of them said that the 15 percent was not the change achieved by fiber alone. It was achieved when people changed the saturated fat in their diet and added fiber."
Ernst believes that the best controlled and most practical research on oat bran fiber's cholesterol-lowering properties has been done by Linda Van Horn, Ph.D., R.D., of the Northwestern University Medical School. Dr. Van Horn set out to determine if adding oat bran or oatmeal to a low-fat, cholesterol-lowering diet would produce additional cholesterol-lowering benefits.
"Unfortunately, the media have frequently looked only at the oat component and have ignored the fact that a fat-modified diet is the most effective way of lowering blood cholesterol," Dr. Van Horn says.
In both of her studies, all participants followed a low-fat, cholesterol-reducing diet. The control groups continued on this diet alone throughout the studies' duration, whereas the experimental groups added 56 grams (two ounces dry, equaling two cups cooked) of oat bran to their daily low-fat diet. Dr. Van Horn and her colleagues recommended that at least half the bran be eaten as oatmeal or oat bran cereal and the remainder be eaten in the form of a muffin or other recipe.
In both studies, the groups that added oatmeal or oat bran to their daily food intake achieved an additional two to three percent reduction in serum cholesterol over and above that caused by the fat-modified diet alone.
Scientists believe that the cholesterol-lowering properties of oats are due to the water-soluble fiber, specifically perhaps a gum called beta-glucan common in oats, which, in purified form, also has been shown to lower serum cholesterol, according to Dr. Van Horn.
"So the bottom line is that oats, indeed, can be a helpful part of a fat-modified diet and a lifestyle that lowers serum cholesterol," says Dr. Van Horn. "But they're probably not the only food that has that effect. Oats are among a variety of foods that can be included in the diet to produce the desired result."
Dr. Van Horn believes that once research is done on other foods containing water-soluble fiber, such as beans, barley, carrots and fruits, a precise picture of their cholesterol-lowering ability will make firm guidelines possible. At this point, she recommends these foods not only for their potential cholesterol-lowering abilities, but also because each has a distinctive combination of important nutrients for a varied, balanced diet.
Dr. Van Horn applauds the renewed public interest in dietary behavior that includes sources of water-soluble fiber. "For too long, we have spent our time telling people what not to eat," she says. "We now believe it may be better to tell them what to eat."
Despite the hoopla surrounding oat bran, however, it's important to point out that no one food can correct the faults of an otherwise unhealthy diet. Some people seem to think that oats are like a miracle drug that will suck cholesterol out of the bloodstream regardless of what else they eat each day.
The biggest dietary problem in the United States, Dr. Van Horn says, remains our intake of fat.
"You can't eat your cheesecake then have an oat bran chaser and expect your cholesterol to go down," she says. "There are no magic bullets. Adding oat bran to the diet has maximum benefit as part of an overall lifestyle approach to lowering risk."
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|Title Annotation:||includes recipe|
|Date:||Nov 1, 1989|
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