Zitat:
Circulation. 1993 Aug;88(2):523-33.
Does fish oil lower blood pressure? A meta-analysis of controlled trials.
Morris MC, Sacks F, Rosner B.
Department of Epidemiology, Harvard School of Public Health.
BACKGROUND. In a meta-analysis of 31 placebo-controlled trials on 1356 subjects, we examined the effect of omega-3 fatty acids in fish oil on blood pressure by grouping studies that were similar in fish oil dose, length of treatment, health of the subjects, or study design. METHODS AND RESULTS. The mean reduction in blood pressure caused by fish oil for the 31 studies was -3.0/-1.5 mm Hg (95% confidence intervals: systolic blood pressure: -4.5, -1.5; diastolic blood pressure: -2.2, -0.8). There was a statistically significant dose-response effect when studies were grouped by omega-3 fatty acid dose: -1.3/-0.7 mm Hg at doses < or = 3 g/d, -2.9/-1.6 mm Hg at 3.3 to 7 g/d, and -8.1/-5.8 mm Hg at 15 g/d. Both eicosapentaenoic acid and docosahexaenoic acid were significantly related to blood pressure response. There was no effect on blood pressure in eight studies of "healthy" persons (mean reduction, -0.4/-0.7 mm Hg) at an overall mean dose of 4.2 g omega-3 fatty acids/d. By contrast, there was a significant effect of -3.4/-2.0 mm Hg in the group of hypertensive studies with a mean fish oil dose of 5.6 g/d and on systolic blood pressure only in six studies of hypercholesterolemic patients (-4.4/-1.1 mm Hg) with a mean dose of 4.0 g/d. A nonsignificant decrease in blood pressure was observed in four studies of patients with atherosclerotic cardiovascular disease (-6.3/-2.9 mm Hg). Variations in the length of treatment (from 3 to 24 weeks), type of placebo, and study design (crossover or parallel groups) did not appear to account for inconsistent findings among studies. CONCLUSIONS. There is a dose-response effect of fish oil on blood pressure of -0.66/-0.35 mm Hg/g omega-3 fatty acids. The hypotensive effect may be strongest in hypertensive subjects and those with clinical atherosclerotic disease or hypercholesterolemia.
Zitat:
Arch Intern Med. 1993 Jun 28;153(12):1429-38.
Does supplementation of diet with 'fish oil' reduce blood pressure? A meta-analysis of controlled clinical trials.
Appel LJ, Miller ER 3rd, Seidler AJ, Whelton PK.
Welch Center for Prevention, Epidemiology, and Clinical Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Md.
BACKGROUND: Several lines of evidence suggest that supplementation of diet with omega-3 polyunsaturated fatty acids (omega-3 PUFA), commonly referred to as fish oils, may reduce blood pressure (BP). However, most clinical trials of omega-3 PUFA supplementation have been of insufficient size to detect relevant BP changes. METHODS: We conducted a meta-analysis of 17 controlled clinical trials of omega-3 PUFA supplementation. To estimate an overall effect of omega-3 PUFA supplementation on BP, we calculated the net BP change in each trial (BP delta in omega-3 PUFA group minus BP delta in control group), which was then weighted according to the inverse of the variance. RESULTS: In the 11 trials that enrolled normotensive individuals (n = 728), omega-3 PUFA supplementation led to significant reductions of systolic BP (SBP) and diastolic BP (DBP) in two and one trials, respectively. In the six studies that enrolled untreated hypertensives (n = 291), significant reductions of SBP and DBP were present in two and four trials, respectively. Weighted, pooled estimates of SBP and DBP change (mm Hg) with 95% confidence intervals were -1.0 (-2.0 to 0.0) and -0.5 (-1.2 to +0.2) in the trials of normotensives, and -5.5 (-8.1 to -2.9) and -3.5 (-5.0 to -2.1) in the trials of untreated hypertensives. In 13 of 17 studies, trial duration was less than 3 months. Doses of omega-3 PUFA tended to be high (average dose > 3 g/d in 11 trials). The magnitude of BP reduction was greatest at high BP but was not significantly associated with dose of omega-3 PUFA. Side effects, most commonly eructation and a fishy taste, occurred more frequently in omega-3 PUFA participants than in control participants (28% vs 13%, P < .001). CONCLUSIONS: Our analyses indicate that diet supplementation with a relatively high dose of omega-3 PUFA, generally more than 3 g/d, can lead to clinically relevant BP reductions in individuals with untreated hypertension. However, use of omega-3 PUFA as antihypertensive therapy will require demonstration of long-term efficacy and patient acceptability of lower doses
