Implications of malnutrition in chemical carcinogenesis.

Epidemiological data indicate that life style, including dietary "imbalances", play a major role in etiology of human cancers. Although two thirds of the world population suffer from varying grades of protein-caloric malnutrition (PCM) today, no consistent pattern is found to be associated wih PCM both in man and laboratory animals. At the tissue level, depression of cellular proliferation by prolongation of DNA-synthetic phase is a characteristic lesion of PCM. Due to changes in liver mixed function oxidases, metabolism of drugs is affected. The cell-mediated immunity is depressed and there is a defective mobilisation of macrophages. These alterations would modulate carcinogenesis; some tend to enhance, while others inhibit tumorigenesis. The balance of evidence suggest that PCM is unlikely to have dominant modulating influence on carcinogenesis.