We’re all creatures of fads and fancies, and medicine is just as subject to these fleeting fashions as the world of haute couture. Few things date as quickly as yesterday’s health craze. One minute it’s jogging, the next it’s antioxidants or Transcendental meditation. We embrace these fads with eager expectation, then toss them aside like discarded toffee papers, never stopping to think that they might contain nuggets of truth which could be adopted with benefit into our permanent life styles.
Some of you will be old enough to recall the 1960s vogue for eating high fibre foods. The impetus for this crusade stemmed largely from the pioneering work of Dr Denis Burkitt, a leading member of Britain’s Medical Research Council, who hit on the idea that the switch to heavily processed foods might be responsible for the high incidence of bowel disease in the Western world. To test this concept he set out to compare the bowel motions of native Africans with those of English schoolboys and military personnel. In one field trial he found that Ugandan villagers eating a high fibre diet of indigenous fruits and cereals produced an average of 470 grams of faeces a day, which passed through their bowels in roughly 36 hours. This was more that four times as heavy as the stools produced by a typical sailor in the Royal Navy, which took more than twice as long to pass through the gut. Identical results were obtained when the bowel activities of the Africans were compared with those of English public school boys, whose stools were often rock hard rather that soft and moist. Burkitt felt that this probably explained their increased risk of constipation, which at the time was often described as ‘the white man’s disease’. He also believed that the dietary variance could well explain the Westerners’ increased likelihood of developing bowel cancer, since the more time the bowel contents take to pass through the gut the longer the intestinal walls are exposed to dietary toxins and carcinogens. One further study helped to clinch his thesis. When Africans first arrived in America they suffered remarkably little bowel disease. Subsequently, when they exchanged their traditional diet of maize, millet and
beans for ‘civilised’ foodstuffs, like white bread, sugar and jam, they faced a much greater chance of developing bowel diseases such as constipation, diverticulitis, appendicitis, polyps and cancer. Dr Burkitt suggested that the addition of two tablespoonfuls of bran, or five ounces of wholemeal bread, to the typical Western diet would provide sufficient fibre to improve bowel function and help prevent disease.
Animals like cows and rabbits can break down the cellular walls of grasses and plants. We can’t, because we lack the enzyme systems needed to digest cellulose. This means that the insoluble fibres we get from vegetables, fruits and cereals aren’t a source of nourishment; nevertheless they form an essential ingredient of a well-adjusted diet. One vital function they serve is to create a feeling of fullness, which helps to curb our craving for cookies and candy and other calorie-rich confections. Some twenty years after the publication of Denis Burkitt’s best selling book ‘Taking the Rough with the Smooth’, the Royal College of Physicians published a report which confirmed that eating roughage helps to prevent obesity. This encouraged Audrey Eyton to write ‘The F-Plan Diet’, a slimming regime which was a publishing sensation in its day, selling millions of copies around the world in numerous foreign language editions. Now the book is yesterday’s news, with second-hand copies available on the internet for just 50p. Why has the idea ceased to capture the public imagination? In the intervening years there’s been no revolution in human biochemistry, and no essential change in our essential dietary needs.
Today doctors agree that people consuming diets rich in roughage have a reduced risk of chronic ailments like heart disease, obesity, late-onset diabetes and certain types of cancer. A study carried out by a team of researchers at the University of Sheffield, for instance, showed that women who have the highest intake of fibre cut their breast cancer risk by half. The message seems clear. If we want to maintain a high level of health, and reduce the risk of succumbing to the chronic diseases of Western civilization, we need to eat less concentrated, processed food and step up our intake of fresh fruit and vegetables, eaten either raw or lightly cooked. This is a simple habit to adopt and one which should be incorporated as part of everyone’s dietary regime.