Effects of marine-derived omega-3 fatty acids on systemic hemodynamics at rest and during stress: a dose-response study

Abstract

Background: Omega-3 fatty acids reduced heart rate (HR) and blood pressure (BP) in some studies, but dose-response studies are rare, and little is known about underlying mechanisms.

Purpose: We examined effects of 0.85 g/day eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) (low dose) and 3.4 g/day EPA + DHA (high dose) on HR and systemic hemodynamics during rest, speech, and foot cold pressor tasks.

Methods: This was a dose-response, placebo-controlled, double-blind, randomized, crossover trial (8-week treatment, 6-week washout) in 26 adults.

Results: Throughout the testing sessions, HR was reduced in a dose-dependent manner. The high dose reduced BP and stroke volume and increased pre-ejection period. Reductions in BP were associated with increases in erythrocyte omega-3 fatty acids.

Conclusions: High-dose long-chain omega-3 fatty acids can reduce BP and HR, at rest and during stress. These findings suggest that at-risk populations may achieve benefits with increased omega-3 intake. The trial was registered on ClinicalTrials.gov (NCT00504309).

Fig. 1

Omega-3 fatty acids significantly reduced heart rate, at rest and during stress. HR was dose-dependently different by treatment (p<0.0001), and this pattern was evident throughout the rest and stressor periods. Relative to placebo, mean HR (collapsing across tasks) was reduced by 2.4 bpm following the low dose (p=0.003) and 4.0 bpm following the high dose (p<0.0001). Reductions in HR were greater with the high dose vs. low dose (p=0.02). *Resting HR differed for the placebo and high dose by 4.0 bpm (p=0.004)

Fig. 2

Changes in the omega-3 index significantly predicted changes in blood pressure. Change in the omega-3 index (EPA + DHA of erythrocytes) relative to placebo treatment was used as a predictor of changes in mean arterial pressure during reactivity sessions relative to placebo treatment (Minitab v.16, State College, PA). The slope of the line did not differ by treatment and the two treatments were pooled for the analysis. The regression equation is ΔMAP=2.03–1.07 Δomega-3 index