ABSTRACT
In studies of cancer cases and controls in Norway and Minnesota, Bjelke has observed that milk and several vegetables have been eaten less frequently by colorectal cancer cases than by controls. In a case-control of gastric cancer in New York, Graham et al. have observed a higher consumption of uncooked vegetables by controls than by gastric cancer cases. There are several possible mechanisms for the anticancer effect of vitamin A. Several vitamin A compounds and analogs are able to inhibit the in vitro microsomal mixed-function oxidases that metabolize carcinogenic polycyclic aromatic hydrocarbons (PAH). Werner et al. have studied the effect of ascorbic acid on small intestine cancer included by N-ethyl-N-nitro-N-nitrosoguanidine (ENNG) in rats. Weisburger et al. have observed a greater incidence of stomach cancer in populations consuming low levels of vitamin E and certain other selected micro nutrients. In general the blood of cancer patients contains less selenium than the blood of healthy individuals.
