Fish oil and neurovascular control in humans.
The antihypertensive influence of fish oil is controversial, and the mechanisms remain unclear. Because the inverse relation between fish oil and hypertension appears to be partially dependent on the degree of hypertension, we tested the hypothesis that fish oil would elicit more dramatic reductions in mean arterial pressure (MAP) and muscle sympathetic nerve activity (MSNA) in prehypertensive (PHT) compared with normotensive (NT) subjects. Resting MAP, MSNA, and heart rate (HR) were examined before and after 8 wk of fish oil (9 g/day; 1.6 g eicosapentaenoic acid and 1.1 g docosahexaenoic acid) or placebo (olive oil; 9 g/day) in 38 NT (19 fish oil; 19 placebo) and 29 PHT (15 fish oil; 14 placebo) volunteers. Fish oil did not alter resting MAP, MSNA, or HR in either NT (80 ± 1 to 80 ± 1 mmHg; 11 ± 2 to 10 ± 1 bursts/min; 71 ± 2 to 71 ± 2 beats/min) or PHT (88 ± 2 to 87 ± 1 mmHg; 11 ± 2 to 10 ± 2 bursts/min; 73 ± 2 to 73 ± 2 beats/min) subjects. When NT and PHT groups were consolidated, analysis of covariance confirmed that pretreatment resting MAP was not associated with changes in MSNA after fish oil. In contrast, pretreatment resting HR was correlated with changes in MSNA (r = 0.47; P = 0.007) and MAP (r = 0.42; P < 0.007) after fish oil but not placebo. In conclusion, fish oil did not alter sympathetic neural control in NT or PHT subjects. However, our findings suggest that fish oil is associated with modest sympathoinhibition in individuals with higher resting heart rates, a finding that is consistent with a recent meta-analysis examining the relations among fish oil, HR, and the risk of cardiovascular disease.
Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, USA. jcarter@mtu.edu
Jason R
JR
Carter
Christopher E
CE
Schwartz
Huan
H
Yang
Michael J
MJ
Joyner
D000328:Adult; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000627:therapeutic use*; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000627:therapeutic use*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008824:Michigan; D018482:Muscle, Skeletal / Q000294:innervation*; D058246:Prehypertension / Q000188:drug therapy* / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
D000959:Antihypertensive Agents; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid