EPA and DHA have divergent effects on serum triglycerides and lipogenesis, but similar effects on lipoprotein lipase activity: a randomized controlled trial.

Background Comparative studies suggest that DHA may have stronger serum triglyceride–lowering effects than EPA; however, the molecular basis for this differential effect remains unexplored in humans. Differential regulation of lipogenesis and triglyceride clearance are 2 possible mechanisms of action. Objectives We compared the effects of EPA and DHA supplementation on serum triglycerides, markers of lipogenesis, and lipoprotein lipase (LPL) activity in adults participating in a double-blind, multiarm, placebo-controlled parallel-group randomized trial. Lipogenesis was assessed with the lipogenic index and compound specific isotope analysis (CSIA). Methods Young, healthy normolipidemic men and women (n  = 89; 21.6 ± 0.23 y; mean ± SEM) were randomly allocated into 1 of 3 supplement groups for 12 wk: 1) olive oil, 2) ∼3 g EPA/d, and 3) ∼3 g DHA/d. Omega-3 supplements were provided in triglyceride form. Blood was collected before and after supplementation for the analysis of fatty acids and preheparin LPL activity. Variations in the ¹³C:¹²C ratio (δ¹³C) of palmitate (16:0) and linoleate (18:2n–6) were measured by CSIA. Results DHA supplementation reduced blood triglycerides (0.85 ± 0.04 mmol/L to 0.65 ± 0.03 mmol/L; P  < 0.01), with no change seen with EPA supplementation. DHA supplementation did not change the lipogenic index or δ¹³C-16:0, whereas EPA supplementation increased the lipogenic index by 11% (P  < 0.01) and δ¹³C-16:0 (P  = 0.03) from −23.2 ± 0.2 to −22.8 ± 0.2 milliUrey ± SEM. Conclusions Reduced triglyceride concentrations after DHA supplementation are associated with increased LPL activity, whereas the null effect of EPA supplementation on blood triglycerides may stem from the concomitant increases in lipogenesis and LPL activity. Further investigation of the differential triglyceride-lowering effects of EPA and DHA is warranted in both normolipidemic and hyperlipidemic individuals. This trial was registered at clinicaltrials.gov as NCT03378232. [ABSTRACT FROM AUTHOR]