Differential eicosapentaenoic acid elevations and altered cardiovascular disease risk factor responses after supplementation with docosahexaenoic acid in postmenopausal women receiving and not receiving hormone replacement therapy

Abstract

Background: Dietary docosahexaenoic acid (DHA) has triacylglycerol-lowering potential and undergoes in vivo retroconversion to eicosapentaenoic acid (EPA) in humans. Hormone replacement therapy (HRT) influences circulating lipid concentrations and fatty acid metabolism. DHA supplementation has not been studied in postmenopausal women.

Objective: We studied the effects of supplementation with DHA (free of EPA) on the resulting elevation in EPA and on selected cardiovascular disease risk factors in postmenopausal women.

Design: Women receiving (n = 18) and not receiving (n = 14) HRT completed a randomized, double-blind, placebo-controlled crossover trial with a DHA supplement (2.8 g DHA/d). A washout period of > or =6 wk divided the two 28-d intervention periods. Fasting blood samples were collected for analysis.

Results: In all women, DHA supplementation was associated with significant changes (P < 0.05), including 20% lower serum triacylglycerol concentrations, 8% higher HDL-cholesterol concentrations, a 28% lower overall ratio of serum triacylglycerol to HDL cholesterol, and a 7% decrease in resting heart rate. DHA supplementation resulted in a 45% lower net increase (P = 0.02) in EPA and a 42% lower (P = 0.0028) estimated percentage retroconversion of DHA to EPA [DeltaEPA/(DeltaEPA + DeltaDHA) x 100] in women receiving than in those not receiving HRT.

Conclusion: With DHA supplementation, the accumulation of EPA in serum phospholipids is significantly attenuated in postmenopausal women receiving HRT compared with that in women not receiving HRT. DHA supplementation can also favorably influence selected cardiovascular disease risk factors in postmenopausal women.