Sex differences in lipid mediators derived from omega-3 fatty acids in older individuals with low-grade chronic inflammation.

The rate of cardiovascular disease (CVD) death is higher in men than women before age 50 y, but the gap between sexes significantly narrows after menopause. Lipid mediators derived from EPA, DHA and AA play a role in inflammation and CVD. The aim of our study was to assess whether plasma concentrations of these lipid mediators differ between postmenopausal women and men. Twelve postmenopausal women and 9 men with low-grade chronic inflammation completed a randomized, double-blind, crossover study consisting of a 4-week lead-in placebo phase (3 g/d high-oleic acid sunflower oil) followed by randomization to either 3 g/d DHA or 3 g/d EPA for 10 weeks and crossover for additional 10 weeks, separated by a washout phase. Plasma phospholipid content of EPA, DHA and AA and plasma concentrations of their derived lipid mediators were measured at the end of the placebo lead-in phase (baseline) and the DHA and EPA supplementation phases. There were no sex differences in plasma phospholipid EPA, DHA and AA at baseline and after DHA and EPA supplementation. However, plasma concentrations of lipid mediators derived from EPA, DHA and AA via 15-lipoxygenase were lower in postmenopausal women than men, especially after supplementation. Sex differences in EPA- and DHA-derived lipid mediators with anti-inflammatory and pro-resolving actions may partly explain the faster rise in CVD in postmenopausal women than age-matched men.