n-3 Dietary supplementation and lipid metabolism: Differences between vegetable- and fish-derived oils

The effect of flaxseed oil rich in linolenic acid (ALA), and a mixed oil (flaxseed oil and fish oil) rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the lipid clearance and peroxisome proliferator activated receptors (PPARs) in liver and adipose tissue of rats fed for 30 days with the two oils was evaluated. The results showed that after treatment with the mixed oil the hematic triacylglycerol content was significantly decreased compared to control animals. Regarding the tissue distribution of the major omega-3 fatty acids, both oils were able to increase ALA, EPA, docosapentaenoic acid (DPA) in liver and adipose tissue; and DHA solely in the adipose tissue. Finally the treatment with either flaxseed or mixed oil increased hepatic PPAR-γ expression but only the mixed oil enhanced the hepatic expression of PPAR-α. No effect on adipose tissue PPAR-γ expression was observed with both oils’ treatment.