People who ate a high-fiber diet decreased their risk of dying over a nine year period compared to those who ate less fiber. Eating a diet rich in fiber has long been known to help keep your digestive tract working properly. It’s also thought to lower the risk of heart disease, some cancers and diabetes. Now, a new study suggests it could reduce the risk of death from cardiovascular, infectious and respiratory diseases.
A study included 219,123 men and 168,999 women ages 50 to 71 years of age. when the study began. Researchers from the National Cancer Institute examined food surveys completed by the participants in 1995 or 1996. After nine years about 11,000 people died and researchers used national records to determine the cause.
Dietary fiber acts by changing the nature of the contents of the gastrointestinal tract, and by changing how other nutrients and chemicals are absorbed. Soluble fiber absorbs water to become a gelatinous, viscous substance and is fermented by bacteria in the digestive tract. Insoluble fiber has bulking action and is not fermented, although a major dietary insoluble fiber source, lignin, may alter the fate and metabolism of soluble fibers.
Chemically, dietary fiber consists of non-starch polysaccharides such as arabinoxylans, cellulose and many other plant components such as resistant dextrins, inulin, lignin, waxes, chitins, pectins, beta-glucans and oligosaccharides. A novel position has been adopted by the US Department of Agriculture to include functional fibers as isolated fiber sources that may be included in the diet. The term “fiber” is something of a misnomer, since many types of so-called dietary fiber are not fibers at all.
Advantages of consuming fiber are the production of salubrious compounds during the fermentation of soluble fiber, and insoluble fiber’s ability (via its passive hygroscopic properties) to increase bulk, soften stool and shorten transit time through the intestinal tract.
People who ate at least 26 grams per day were 22% less likely to die than those who consumed the least amount of fiber, or 13 grams per day or less. Men and women who consumed diets higher in fiber also had a reduced risk of cardiovascular, infectious and respiratory diseases. Getting one’s fiber from grains seemed to have the biggest impact.
Federal dietary guidelines recommend people consume at least 14 grams of fiber per 1,000 calories, so about 28 grams for an average 2,000 calorie-per-day diet. But many experts say Americans don’t get enough.
On average, North Americans consume less than 50% of the dietary fiber levels recommended for good health. In the preferred food choices of today’s youth, this value may be as low as 20%, a factor considered by experts as contributing to the obesity levels seen in many developed countries. Recognizing the growing scientific evidence for physiological benefits of increased fiber intake, regulatory agencies such as the Food and Drug Administration of the United States have given approvals to food products making health claims for fiber.
Written by Sy Kraft, B.A.