Dietary supplementation of α-linolenic acid induced conversion of n-3 LCPUFAs and reduced prostate cancer growth in a mouse model.

BACKGROUND: α-linolenic acid (ALA) is an n-3 polyunsaturated fatty acid (PUFA) and the substrate for long-chain n-3 PUFAs. The beneficial effects of ALA on chronic diseases are still in dispute, unlike those of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

METHODS: The primary objective of this investigation was to evaluate the efficiency of ALA uptake from a vegetable oil source and its subsequent conversion to n-3 long-chain PUFAs (LCPUFAs) in the tissues of growing mice, and to investigate its protective role in a prostate cancer animal model. We carried out the investigation in prostate-specific Pten-knockout mice with specified low-ALA (L-ALA, 2.5%) and high-ALA (H-ALA, 7.5%) diets. Total fatty acids in blood, liver, epididymal fat pad, prostate were detected and prostate weight were adjusted for body weight (mg/25 g).

RESULTS: We found that dietary ALA triggered significant increases in ALA, EPA, docosapentaenoic acid (DPA) and DHA levels and a significant decrease in arachidonic acid levels during the mice's growth stage. A dose-dependent effect was observed for ALA, EPA and DPA, but not DHA. Furthermore, the average prostate weights in the L-ALA and H-ALA groups were lower than those in the control and n-6 groups, and similar to those in the EPA and n-3 groups.

CONCLUSIONS: Our data suggest that dietary supplementation with ALA is an efficient means of improving n-3 LCPUFAs in vivo, and it has a biologically effective role to play in prostate cancer, similar to that of fish oils.