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Human Biochemistry Research Unit School of Pathology of the University of the Witwatersrand and the South African Institute for Medical Research PO Box 1038 Johannesburg, 2000 South Africa E-mail: alexw{at}mail.saimr.wits.ac.za
Dear Sir:
In Kostoff's comments on my letter (1), he emphasizes the importance of energy restriction and the use of whole foods. His views serve to underline the various nutrition and health lessons that have been learned from experimental studies of animals and from epidemiologic and other studies of humans. I recently discussed the powerful bearing of energy restriction in some detail in an editorial on energy intake and longevity (2). In brief, there is no doubt that the manner of life pursued, both in reference to diet and not, largely determines the velocity of aging and the degree of proneness to chronic disorders or disease.
Currently, adequate evidence exists that many population groups (eg, certain Mediterranean populations, vegetarians, and Seventh-day Adventists) whose manners of life, in varying measure, conform with current dietary guidelines have lower occurrences of degenerative diseases and longer life expectations (2). A recent example can be found in the Norwegian County Study (3); in this noninterventional prospective study, the subjects' mean intake of whole-grain bread was 4 times that consumed in the United States, and their mortality rates from the chronic diseases of lifestyle were lower. Furthermore, in a recent prospective study in Sweden, obesity was found to be associated with more forms of cancer than previously reported (4).
Despite the numerous guidelines put forward, as indicated by Kostoff and myself (2), few persons indeed are following them. To avoid or lessen the development of chronic disorders and diseases, the young should receive major attention. Nowadays, for many children, the time spent watching television at home equals the time spent on lessons at school; moreover, in their viewing, children are bombarded with food advertisements, many of which conflict with nutritional guidelines. Additionally, a diminishing proportion of children participate in school games. In the recent US third National Health and Nutrition Examination Survey, it was found that few dietary changes have been made since the previous survey conducted in 1976 (5). Not least of problems among young adults are the increasing incidence of smoking, alcohol consumption, and drug use (2).
A major obstacle to altering diets is the higher cost of the diets described in the guidelines. For example, a study in London showed that it costs £106 ($135)/wk for a single man aged 18–30 y to live a healthy lifestyle (6). The authors estimated that it costs £3 ($4)/wk to keep and use a bicycle or a pair of running shoes. Food costs included the price of 2 portions of oily fish weekly and 5 portions of fresh fruit or vegetables daily. In the United Kingdom, the national minimum wage just covers the cost of the healthy lifestyle described.
Perhaps the most important point regarding the unwillingness of the masses to make health improvement changes, however, is that present-day living in most Western populations is consistent with long life expectations, far longer than even in the recent past (2). By far the main burden of mortality from our major "killers," such as coronary artery disease, stroke, and cancer, occurs in late middle age. Notwithstanding, research on longevity should continue, if only for the small moieties of populations who desire to make the requisite lifestyle changes.
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