Influence of different fats (Soybean oil, palm olein or hydrogenated soybean oil) on chemically-induced mammary tumors in rats

Abstract

Mammary tumors were induced in female Sprague-Dawley rats by a single feeding of 7,12-dimethylbenz(a)anthracene (DMBA). The rats (21/group) were fed 5 or 20% of soybean oil (SBO), palm oil (PO), or hydrogenated soybean oil (HS). Where needed the diet of the rats fed PO or HS was augmented with SBO to ensure adequate essential fatty acid content. At 5% fat, tumor incidence was highest in SBO-fed rats. Tumor multiplicity, mean tumor weight and tumor burden were all highest in rats fed HS and lowest in those fed PO. At 20% dietary fat, tumor incidence was lowest in rats fed HS and similar in those fed SBO or PO. Tumor multiplicity, mean tumor weight and tumor burden were lowest in rats fed PO and highest in rats fed SBO. Our data suggest that palm oil is less active in the promotion of chemically induced (DMBA) mammary tumors in female rats than either soybean oil or hydrogenated soybean oil.