Effects of a high-linoleate and a high-alpha-linolenate diet on spontaneous mammary tumourigenesis in mice.

SHN mice were fed a high-linoleate diet, a high-alpha-linolenate diet or a control diet. Spontaneous mammary tumourigenesis was significantly inhibited in the high alpha-linolenate group compared to the other two groups, while little difference was observed among groups in the rates of lung metastasis. The dietary alpha-linolenate/linoleate balance affected the fatty acid patterns of tissue lipids. The triacylglycerol/phospholipid ratios and the fatty acid patterns were significantly different between the mammary glands and the mammary tumours. The results indicate that the dietary alpha-linolenate/linoleate balance affects the fatty acid composition and, in turn, spontaneous mammary tumourigenesis in mice.