Lowering Effects of n-3 Fatty Acid Supplements on Blood Pressure by Reducing Plasma Angiotensin II in Inner Mongolia Hypertensive Patients: A Double-Blind Randomized Controlled Trial.

Whether n-3 fatty acid (FA) has hypotensive actions among Chinese adults remains inconclusive. Hypertensive patients from Inner Mongolia, China ( n = 126) were recruited to a double-blind, randomized controlled trial. We investigated the effects of n-3 FA supplements on blood pressure (BP, mm Hg), plasma concentrations of angiotensin II (Ang II, pg/mL), and nitric oxygen (NO, μmol/L), using fish oil ( n = 41, 4 capsules/day, equivalent to 2 g of eicosapentaenoic acid plus docosahexaenoic acid) and flaxseed oil ( n = 42, 4 capsules/day, equivalent to 2.5 g of α-linolenic acid). Comparing to the control group (corn oil, n = 43), the mean systolic BP (-4.52 ± 9.28 vs -1.51 ± 9.23, P = 0.040) and the plasma Ang II levels (-12.68 ± 10.87 vs -4.93 ± 9.08, P = 0.023) were significantly lowered in the fish oil group, whereas diastolic BP ( P = 0.285) and plasma NO levels ( P = 0.220) were not. Such findings suggest that marine-based n-3 FA has a hypotensive efficacy in Chinese hypertensive patients possibly through inhibiting Ang II-dependent vasoconstrictions.