Eat more fiber and you just may live longer.
That's the message from the largest study of its kind to find a link between high-fiber diets and lower risks of death not only from heart disease, but from infectious and respiratory illnesses as well.
The government study also ties fiber with a lower risk of cancer deaths in men, but not women, possibly because men are more likely to die from cancers related to diet, like cancers of the esophagus. And it finds the overall benefit to be strongest for diets high in fiber from grains.
Most Americans aren't getting enough roughage in their diets. The average American eats only about 15 grams of fiber each day, much less than the current daily recommendation of 25 grams for women and 38 grams for men, or 14 grams per 1,000 calories.
In the new study, the people who met the guidelines were less likely to die during a nine-year followup period.
The men and women who ate the highest amount of fiber were 22 percent less likely to die from any cause compared with those who ate the lowest amount, said lead author Dr. Yikyung Park of the National Cancer Institute.
The study, appearing in Monday's Archives of Internal Medicine, included more than 388,000 adults, ages 50 to 71, who participated in a diet and health study conducted by the National Institutes of Health and the AARP.
The researchers took into account other risk factors including weight, education level, smoking and health status and still saw lower risks of death in people who ate more fiber.
The evidence for fiber's benefits has been strongest in diabetes and heart disease, where it is thought to improve cholesterol levels, blood pressure, inflammation and blood sugar levels. Fiber's benefits also may come from its theorized ability to bind to toxins and move them out of the body quicker. By making people feel full, high-fiber diets can promote weight loss, which has its own health-promoting effects.
However it works, fiber may also offer a prevention benefit against killers like pneumonia and flu, the new study suggests.
Fiber is found in fruits, vegetables and beans, all key to a healthy diet. But fiber from grains was most strongly tied to the lowered risk in the study.
"That's what seemed to be driving all these relationships," said Lawrence de Koning of the Harvard School of Public Health, a co-author of an editorial in the journal.
Whole grains also contain vitamins and minerals, which may play a role in reducing risk, he said. For that reason, supplements may not be as effective.