Effects of vitamin A and E supplementation to diets containing two different fat levels on methylnitrosourea-induced mammary carcinogenesis in female SD-rats.

The aim of this study was to elucidate the effects of dietary vitamin A and E supplementation on tumorigenesis in correlation to the fat content of the respective diet in an animal model. One hundred and twenty female SD rats were initiated intravenously with 25 mg MNU kg-1 on day 50 of life. For a period of 6 months, beginning after the day of initiation, all animals received a semisynthetic diet containing 25% or 45% of the energy as fat, supplemented either with a 10-fold higher amount of naturally occurring vitamins A and E than in rat standard diets or, with a normal level of these vitamins. The experiment showed: (1) Vitamin A and E supplementation showed no significant chemopreventive effect against mammary tumour development. (2) This result was independent from the supplied fat level of the respective diet. (3) The fat content per se did not significantly influence mammary tumorigenesis.