Fiber in the Diet

American physicians have contended for decades that it does not matter whether a person has one or two bowel movements a day or only two or three a week. Now that view has been challenged by British and South African medical scientists who suggest that what commercials call "regularity" may be a matter of life and death. Too few bowel movements and too little bulk in the stools, they write in the Journal of the A.M.A., may partly explain the occurrence of such varied disorders as heart and gall-bladder disease, appendicitis, diverticulosis, varicose veins, clotting in the deep veins, hiatal hernia and cancer of the large intestine.

This provocative idea was conceived by British Surgeons Denis Burkitt* and Neil Painter and Biochemist Alexander Walker in an attempt to explain the differences reported in disease rates between Africans living under tribal conditions and the peoples of Western countries where, they say, there has been a rapid increase in certain illnesses in less than a century.

Medical statistics are admittedly imprecise, and are distorted by improvements in diagnosis. Nevertheless, Burkitt and his colleagues believe that the increases in these diseases are real, and were caused by a change in the type of food eaten in developed countries, particularly in food that reaches the large bowel with the least change: indigestible fiber, the roughest of roughage. Until about 1890, they say, the pound of bread that average Britons and Americans ate every day contained much indigestible fiber; because of more elaborate milling techniques, bread now contains less fiber and people are eating less of it. This, the researchers say, has affected both the frequency and the nature of their bowel movements, which in turn have affected their health.

The scientists conducted elaborate experiments in which volunteers in England, India and Africa had their bowel movements clocked and their feces weighed. Among the results of the study: peoples living under primitive conditions, on diets high in indigestible fibers, passed from 2 1/2 to 4 1/2 times as much feces as sailors in the Royal Navy, and were relatively free of many of the diseases studied.

The ways in which low-weight, sluggish bowel movements might contribute to so many diverse diseases are complex and indirect, the Burkitt group concedes. Diverticulosis--in which the large bowel is deeply pitted and fecal material is trapped in the crevices--appears to be directly related to a diet rich in such highly refined carbohydrates as white flour and sugar. Tumors, both benign and malignant, are related to biochemical and bacterial changes caused by long retention of feces. As for heart disease: "Evidence is accumulating that shows that the removal of fiber from the diet raises serum cholesterol levels, a process that predisposes to coronary heart disease."

In short, the Burkitt team says, the physiological function of cereal fiber has been largely ignored because the fiber supplies no calories and has scarcely any nutritional value. Now, if the scientists' findings are confirmed, the time has come to rely not on commercial chemical laxatives but on nature's own brands --root vegetables, unpolished rice and such other unprocessed cereals as wheat, corn, barley and oats--to put fiber back into the diet of modern man.

* Famed for having distinguished a curable cancer of the jaw (Burkitt's lymphoma) in children in some parts of Africa.

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