Medical Edge Newspaper Column

Whole Grains: Not Only Good For You,
They Taste Good, Too

Aug. 14, 2006
DEAR MAYO CLINIC:
What's the difference between whole grain and high fiber? -- Rochester, Minn.

ANSWER:
One is a major, though nonexclusive, vehicle for the other. Whole grains -- the unadulterated seeds of cereal grasses such as wheat, rice and barley -- are good sources of fiber, and they are rich in other nutritionally valuable things as well. Whole grains are not the only sources of fiber. Other plant foods, such as fruits and vegetables, are high in fiber too.

Fiber, which comes in two forms (water-soluble and water-insoluble), is the part of plant food that your body cannot digest. Nonetheless, fiber performs some important bodily functions. When soluble fiber dissolves it forms a spongy complex that helps lower blood cholesterol by soaking up surplus cholesterol and removing it from the body. Soluble fiber also slows absorption of sugar, thereby lowering blood sugar levels. These effects reduce the risk of heart disease, diabetes and other illnesses.

Insoluble fiber, meanwhile, holds onto water, which serves to bulk up and soften stools so that they easily pass through and out of the digestive system. As a result, the likelihood of problems such as hemorrhoids and constipation, as well as more serious gastrointestinal ailments, is lowered.

Though all plants foods contain both soluble and insoluble fiber, most whole grains -- such as whole wheat and brown rice -- are particularly rich in insoluble fiber. In contrast, fruits, vegetables, legumes (beans, for example) oats and barley are richer in soluble fiber. Thus there is no one "best" source of fiber. We must eat a variety of healthful foods in order to derive all of fiber's benefits.

In a whole grain, most of the fiber is contained in the bran, which is the outer layer of the seed. But the bran is also an abundant source of niacin, thiamin, riboflavin, magnesium, phosphorus, iron and zinc. When grains are milled -- processed, for example, into white flour or white rice -- the bran is removed.

The second part of a whole grain is the germ, from which a new plant sprouts. The germ is rich in many of the same nutrients that are found in the bran, and it also contains some protein, fat, vitamin E, and most everything else the embryonic stage of the plant needs in order to grow. The germ, too, is removed when whole grains are converted to refined grains.

The only component of a whole grain that remains after processing is its third and final part, the endosperm (kernel), which makes up the bulk of the seed. It contains most of the grain's protein and carbohydrates.

In fairness, we must note that a number of nutrients, such as B vitamins, are routinely added to many grain products after milling. But because it is simply not feasible to put everything back, such "enriched" offerings may be adequate in some ways but greatly lacking in others.

Dietitians recommend a diet that includes generous helpings of whole grains and other wholesome foods that are high in fiber and other important nutrients. To help guide meal planning, samples classified by food types are listed on MayoClinic.com . But the granddaddy of all such lists is in the USDA's National Nutrient Database , which enables users to select from hundreds of foods.

Finally, let us cite the greatest incentive of all for recruiting "converts" to healthier eating habits: meals made with whole grains and boasting high fiber content are not only healthful but often delicious. The nutty flavor and chewiness of brown rice makes it perfect for casseroles or pilafs; whole-wheat pasta adds substance and subtlety to traditional pasta dishes; steel-cut oats (whole oat kernels that are cut into small pieces) will give texture to pancakes, cookies and hot cereals. Whole foods, in other words, should make it onto your table simply because they taste good.

-- Jennifer K. Nelson, R.D., Director, Clinical Dietetics, Mayo Clinic, Rochester, Minn.