Effects of Various Dietary Staples on Esophageal Carcinogenesis Induced in Rats by Subcutaneously Administered <italic>N</italic>-Nitrosomethylbenzylamine

Abstract

Previous epidemiologic studies associated large differences of esophageal cancer risk with the nature of the staple diet. In this study, various cereals and dietary staples were fed to inbred BD IX rats for 7 months or longer. N-Nitrosomethylbenzylamine [(MBN) CAS:937-40-6] was given five times subcutaneously between the 45th and 58th day. The percentage of rats with tumors and the mean number of tumors per esophagus were similar when corn, wheat, commercial bird-resistant sorghum, bananas, and polished rice were fed but were strikingly lower when the basis of the diets was millet, red sorghum, brown rice, or potatoes. The number of esophageal tumors was significantly related to the dietary concentration of some minerals and vitamins. Supplementing marginally deficient corn or wheat diets with various combinations of nicotinic acid, riboflavin, zinc, magnesium, molybdenum, and selenium significantly reduced the numbers of esophageal tumors. When the feeding of protective cereals or nutrients was commenced only 150 days after MBN was given, a marked inhibitory effect on the progression of tumors was still observed.