Dietary factors in a study of cancer colon from cancer registry, with special reference to the role of saliva, milk and fermented milk products and vegetable fibre

Abstract

As a result of Cancer Registry, a total of 219 cancers of the gastrointestinal tract were found among 360,510 railway employees and their families during the period 1 January 1968 to 31 December 1973, giving a quinquennial rate of 60.7 per 100,000 of population. Out of these 219 cancers only 37 (16.8%) were of the colon and rectum. These rates are certainly under-estimates of rates in the whole population as our population is below 58 years of age, whereas cancers of the colon and rectum are most frequent after this age. The male:female ratio was 3:1. The aetiological factors which seemed most important were dietary. Diets rich in roughage, cellulose and vegetable fibre and short-chain fermented milk products and the proper chewing of meals ensuring that mucus-rich saliva mixed with the food seemed to be protective factors. Possible important factors are the differences in the cellulose and fibre content in the diets of South Indians as compared with those of North Indians. While the North Indian diets are rich in roughage, cellulose, and vegetable fibres, these are almost completely lacking in the South Indian diets. We have investigated this point further by the examination of faeces in these disparate groups, which showed that whilst vegetable fibres were abundant in the stools of North Indians these were completely absent in those of the South Indians. This may have important implications because of the recent evidence of Popjack, French, and Folley (27) that the fermentation of cellulose and vegetable fibres in the intestines gives rise to large quantities of acetic acid which may thus act in a protective manner on the intracellular mucus of the mucous membrane of the colon in North Indians while giving no such protection to the South Indians. This is because in an acid milieu the mucus of the mucous cells gets precipitated and thus protects the cell whereas in an alkaline milieu the mucus is rendered fluid and escapes from the cell giving rise to cell proliferation, marked increase in mitotic activity and cell atypia which in turn can lead to neoplasia.