Doctors have long recommended eating a high-fiber diet to stay regular. Now scientists know why it can get things moving more smoothly.
Researchers at the Medical College of Georgia and in Japan found that the sticky fiber can wound cells lining the gastrointestinal tract. Rather than being harmed, though, the injured cells release mucus as part of the repair process that helps move things along. The study was published Monday in the online journal PLoS Biology, put out by the Public Library of Science.
The mucus is part of an "adaptive" response from the body to the fiber, said MCG cell biologist Paul McNeil.
"So if in the upper part of the GI tract you're damaging cells due to a high-fiber intake, the best thing to do is to produce a lubricating mass of mucus at that site and let it pass down with the food throughout the remainder of the GI tract, avoiding the problem further down," Dr. McNeil said.
Scientists had known that mucus played a role but weren't sure why different diets produced different amounts.
"It reinforces with me the importance of eating a high-fiber diet," Dr. McNeil said. "And it explains how, in a high-fiber diet, it might be helpful in producing this important lubricating substance."
High-fiber diets heavy on fruits, vegetables and whole grains have long been stressed, said Sheri Loflin, the clinical nutrition manager at Doctors Hospital.
"There are a lot of benefits to it," she said. "I think it helps with weight control when people focus on trying to get 25 grams or more of fiber in a day."
Those foods can help you feel full longer, Mrs. Loflin said, because "those kinds of foods stick with you a little longer."
Literally stick with you, it turns out.
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3 pitted prunes - 1.9 grams
Medium raw peach - 2.3 grams
1 cup cooked carrots - 3.4 grams
4 spears frozen broccoli - 5 grams
1 cup cooked spinach - 7 grams
1 cup green peas - 9.1 grams