Dietary fiber refers to the portion of plants that cannot be digested by enzymes in our digestive system.
The late British surgeon Dr. Denis Burkitt was one of the first scientists to recognize the important health benefits of dietary fiber. He did research in the 1960s and 1970s comparing the pattern of diseases that he observed in African hospitals with his experience in Great Britain. He found some remarkable differences.
For example, in African countries that he researched, there was a very low incidence of colon cancer, hemorrhoids, varicose veins, and cardiovascular disease. He wrote a bestselling book, “Don’t Forget Fiber in Your Diet,” in which he claimed that Western diseases which were rare in Africa was the result of low dietary intake of fiber. The importance of his discovery was not recognized until many years later.
Current health research shows that in western countries such as the United States, very few people consume the recommended amounts of fiber. The average intake of fiber per day for men and women is 18 grams and 15 grams, respectively, according to national surveys. The guidelines recommend a daily minimum intake of 33 grams per day for men and 28 grams per day for women. Burkitt’s original theory for the health benefits of fiber had to do with avoiding constipation and improving regularity. More recent science shows higher levels of fiber intake cause increased amounts of good bacteria in the digestive system.
Additional health benefits that can occur as a result of high-fiber intake include lowering body weight, lowering blood pressure and lowering cholesterol. Furthermore, higher intake of fiber improves cardiovascular health. This seems to occur because of improved cholesterol levels as well as reducing inflammation. In addition, dietary fiber improves the functioning of insulin in our body, which has a favorable health effect. A recent study showed that increasing fiber intake is associated with a lower risk of cancer of the head and neck. One other possible reason that dietary fiber is correlated with improved health outcomes has to do with other foods that a person is consuming along with fiber rich foods, in particular phytochemicals and other healthy nutrients.
In general, processed food has less fiber than unprocessed food. Vegetables, fruits, whole grains and legumes are good sources of fiber.
I highly recommend the intake of adequate amounts of dietary fiber, because of the many health benefits that can accrue, and because of the pleasure that we can experience eating good tasting, healthy foods.
Dr. Mark Roth writes about internal medicine for the Cleveland Jewish News. He is an internal medicine physician with University Hospitals.