Introduction

Since World War II, there has been a marked increase in epidemiological studies on cancer and diet. At first, concern was greatest in relation to potentially toxic chemicals added to the diet, following experimental studies in the 1920s. Such concern motivated much of the deliberations of the joint World Health Organization/Food and Agricultural Organization (WHO/FAO) Committee on food additives and pesticides in the postwar period (WHO, 1958). In the USA, fear of chemical additives culminated in the passage of Public Law 85–929, known as the Delaney Amendment (1958), which banned the use of any carcinogen as a food additive. None the less, the relationship remains controversial. Later research has largely concentrated on the role of macronutrients such as dietary fat, fiber, as well as other normal food constituents.

The National Academy of Sciences (NAS, 1982), after a complete review of the literature available on diet and cancer, reported that:

‘The evidence reviewed by the committee suggests that cancers of most major sites are influenced by dietary patterns. However, the committee concluded that the data are not sufficient to quantitate the contribution of diet to the overall cancer risk or to determine the per cent reduction in risk that might be achieved by dietary modifications.’