06/05/2003 - Articles

Whole Grain Foods Aid Bowel Health

By: Tufts University


Here's another good reason to reach for a whole grain cereal in the morning - an Australian study credits some of the signs of a healthy bowel to a diet that includes whole wheat and rye grain foods. The findings appeared in a recent issue of the American Journal of Clinical Nutrition.

Appraising high-fiber foods

The researchers recruited 28 overweight but otherwise healthy men aged 40 to 65. All followed - in turn - three diet protocols for a 4-week period each: a high-fiber diet that provided 19 grams of its fiber from rye bread and cereal; a high-fiber diet that provided the same amount of fiber from whole wheat foods; and a lower-fiber diet that included refined grain bread and cereals. Lab tests were done on blood and stool samples at the start and end of the 12-week study.

Fiber made a difference

As might be expected, the participants' bowels fared better on the high-fiber diets than on the lower-fiber diet. The high-fiber diets, especially the one that included rye grain, were associated with high blood levels of enterolactone, a by-product of fiber metabolism that may play a role in cancer prevention. These diets were also associated with higher amounts of butyrate, another fiber by-product that helps support beneficial bacteria in the large intestine.

Both high-fiber diets resulted in lower stool amounts of several potentially toxic compounds that are produced in the colon. Fewer toxic substances, say the authors, means less damage to cells and a reduced risk of cancer.

Advice to consumers

It's not yet clear if high fiber foods play a role in lowering the risk of colon cancer. Still, whole grain foods make good nutrition sense from several angles. Since these foods are made with the whole grain, including the fiber and B vitamin-rich outer layers, they provide more nutrients per bite than foods made from refined white flour. The fiber also adds bulk to the diet, thereby increasing satiety so that you may be inclined to eat less.

The researchers who conducted this study focused particularly on foods made with rye, but all types of whole grain foods - whole wheat bread, bran cereal, oatmeal, brown rice - are good choices.

To substantially boost the fiber content of your breakfast, choose a cereal that has at least 5 grams of fiber per serving. And read the labels of breads, crackers, and other grain products to make sure that the first ingredient is whole grain flour - your assurance that the product is actually high in fiber and not just colored to look that way.


Whole-grain rye and wheat foods and markers of bowel health in overweight middle-aged men.
G. McIntosh, M. Noakes, P. Royle,  et al., Amer J Clin Nutr, 2003, vol. 77, pp. 967--974


Created on: 06/02/2003
Reviewed on: 06/05/2003

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