The influence of dietary vitamin E and calcium status on intestinal tumors in rats.
Male Sprague-Dawley rats were fed from weaning low (1-5 ppm) and normal (26-50 ppm) vitamin E diets for 30-34 weeks. Dietary fat was also varied from 5% (Experiment 1) to 20% (Experiments 2 and 3). Intestinal tumors were induced by 1,2-dimethylhydrazine given subcutaneously as 10 weekly doses at 20 mg/kg body wt. Tumor incidence was lower by 30% and burden was 25%-50% lower for low vitamin E rats than for vitamin E-replete rats. This result was independent of the fat content of the diet. In Experiment 3, vitamin E and calcium were assessed for their influence on intestinal tumors at two levels, with dietary vitamin E at 5 and 50 ppm and calcium at 0.2% and 1.0% in a 2 x 2 factorial experiment. The high calcium-low vitamin E diet produced the greatest fall in tumor incidence and burden relative to the other treatments. In this experiment, vitamin E deficiency reduced tumor incidence and calcium supplementation reduced tumor burden, with a significant interaction of the two. However, this group also showed evidence of reduced food intake and kidney change (calcification), which may have confounded the result. This points to a risk associated with this combination of nutrients at these levels in long-term experiments.
McIntosh
G H
GH
Division of Human Nutrition, Commonwealth Scientific and Industrial Research Organization, Adelaide, South Australia.
D019813:1,2-Dimethylhydrazine; D000818:Animals; D001835:Body Weight; D002136:Calcium, Dietary / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage; D004127:Dimethylhydrazines; D002149:Energy Intake; D007414:Intestinal Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D008297:Male; D051381:Rats; D014810:Vitamin E / Q000008:administration & dosage* / Q000097:blood; D014811:Vitamin E Deficiency / Q000503:physiopathology
D002136:Calcium, Dietary; D004041:Dietary Fats; D004127:Dimethylhydrazines; D014810:Vitamin E; D019813:1,2-Dimethylhydrazine