Docosahexaenoic acid reduces resting blood pressure but increases muscle sympathetic outflow compared with eicosapentaenoic acid in healthy men and women

Supplementation with monounsaturated or omega-3 polyunsaturated fatty acids (n-3 PUFA) can lower resting blood pressure (BP) and reduce the risk of cardiovascular events. The independent contributions of the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on BP, and the mechanisms responsible, are unclear. We tested whether EPA, DHA, and olive oil (OO), a source of monounsaturated fat, differentially affect resting hemodynamics and muscle sympathetic nerve activity (MSNA). Eighty-six healthy young men and women were recruited to participate in a 12-wk, randomized, double-blind trial examining the effects of orally supplementing similar to 3 g/day of EPA (n = 28), DHA (n = 28), or OO (n = 30) on resting hemodynamics; MSNA was examined in a subset of participants (n = 31). Both EPA and DHA supplements increased the omega-3 index (P < 0.01). Reductions in systolic BP were greater [adjusted intergroup mean difference (95% confidence interval)] after DHA [-3.4 mmHg (-0.9, -5.9), P < 0.008] and OO [-3.0 mmHg (-0.5, -5.4), P < 0.01] compared with EPA, with no difference between DHA and OO (P < 0.74). Reductions in diastolic BP were greater following DHA [-3.4 mmHg (-1.3, -5.6), P < 0.002] and OO [-2.2 mmHg (0.08, -4.3), P < 0.04] compared with EPA. EPA increased heart rate compared with DHA [4.2 beats/min (-0.009, 8.4), P < 0.05] and OO [4.2 beats/min, (0.08, 8.3), P < 0.04]. MSNA burst frequency was higher after DHA [4 bursts/min (0.5, 8.3), P < 0.02] but not OO [-3 bursts/min (-6, 0.6), P < 0.2] compared with EPA. Overall, DHA and OO evoked similar responses in resting BP; however, DHA, but not OO, increased peripheral vasoconstrictor outflow. These findings may have implications for fatty acid supplementation in clinical populations characterized by chronic high BP and sympathetic overactivation. NEW & NOTEWORTHY We studied the effects of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and olive oil supplementation on blood pressure (BP) and muscle sympathetic nerve activity (MSNA). After 12 wk of 3 g/day supplementation, DHA and olive oil were associated with lower resting systolic and diastolic BPs than EPA. However, DHA increased MSNA compared with EPA. The reductions in BP with DHA likely occur via a vascular mechanism and evoke a baroreflex-mediated increase in sympathetic activity.