Differential effects of EPA versus DHA on postprandial vascular function and the plasma oxylipin profile in men.

Our objective was to investigate the impact of EPA versus DHA on arterial stiffness and reactivity and underlying mechanisms (with a focus on plasma oxylipins) in the postprandial state. In a three-arm crossover acute test meal trial, men (n = 26, 35-55 years) at increased CVD risk received a high-fat (42.4 g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, long chain n-3 PUFA-derived oxylipins, nitrite and hydrogen sulfide, and serum lipids and glucose. Vascular function was assessed using blood pressure, reactive hyperemia index, pulse wave velocity, and augmentation index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P = 0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA- and DHA-derived oxylipins in the acute postprandial state, with an (1.3-fold) increase in 19,20-dihydroxydocosapentaenoic acid evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight into the AIx effect.