Effects of low-dose eicosapentaenoic acid, docosahexaenoic acid and dietary fat on the incidence, growth and cell kinetics of mammary carcinomas in rats.

This study investigated the effects of low-dose eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) on the incidence, tumor growth and cell kinetics of a 7,12-dimethylbenz(a)anthracene-induced mammary carcinoma in rats fed either a high-fat (20% corn oil) or low-fat (0.5% corn oil) diet. Low-dose EPA and DHA completely blocked the stimulatory effect of fat on tumorigenesis, as demonstrated by a decreased number of tumors per group and per tumor-bearing rat. While EPA and DHA inhibited cell kinetics as evidenced by a decreased bromodeoxyuridine-labeling index, their inhibitory effects on tumor size and tumor doubling time were not significant. These data suggest that low-dose EPA and DHA inhibit tumorigenesis rather than tumor growth in the high-fat group.