Fish oils and plasma lipid and lipoprotein metabolism in humans: a critical review.

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.

Does fish oil lower blood pressure? A meta-analysis of controlled trials.

Traditional approaches to prophylaxis of atherosclerosis have focused on one aspect of the pathogenesis of this multifactorial disease, such as platelet function or blood lipids, and therefore have had limited success. Epidemiologic studies show a striking inverse correlation of consumption of fish rich in the two omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, and mortality from cardiovascular disease. In studies of volunteers and patients, reductions in platelet responsiveness, lowering of blood lipids, and improvements of blood flow, as well as improvements in other values implicated in the pathogenesis of atherosclerosis, were induced with eicosapentaenoic and docosahexaenoic acids. These findings indicate that these omega-3 fatty acids have a larger prophylactic potential than traditional approaches. This potential must be scrutinized in meticulously designed and conducted trials with clinical endpoints.

Prophylaxis of atherosclerosis with marine omega-3 fatty acids. A comprehensive strategy

Traditional approaches to prophylaxis of atherosclerosis have focused on one aspect of the pathogenesis of this multifactorial disease, such as platelet function or blood lipids, and there...

Prophylaxis of Atherosclerosis with Marine Omega-3 Fatty Acids

Short- and long-term outcome of percutaneous transluminal coronary angioplasty in chronic dialysis patients.

Haemodialysis patients have an exceptionally high incidence of death from cardiovascular causes, related in part to abnormalities of lipids and platelets. Eskimos, however, have a low incidence of myocardial infarction and have a high dietary intake of fish, rich in omega-3 polyunsaturated fatty acids. We have, therefore, studied the effect of a fish oil MaxEPA, containing 3.6 g of the omega-3 polyunsaturated fatty acid eicosapentaenoic acid on lipids and platelet function in haemodialysis patients. Following 8 weeks of therapy there was a 35% fall in triglycerides, a 10% rise of high-density lipoprotein (HDL) cholesterol, a 36% rise of HDL2 cholesterol fraction and a 54% rise of the HDL2:HDL3 cholesterol ratio. The platelet aggregation to adenosine diphosphate and collagen was significantly reduced. The activated whole-blood clotting time was prolonged from 141 to 153 s, and 69% of patients showed a reduction of factor VIII related antigen which is usually elevated in haemodialysis patients and is thought to be a marker of endothelial damage. The blood pressure fell from 147/82 to 124/74. We have thus shown that a dietary supplement of eicosapentaenoic acid produces potentially beneficial effects on lipids, platelets, and blood pressure and may help to protect against atheroma and thus cardiovascular mortality in high-risk haemodialysis patients.

P.B. Rylance

Papers

Fish oil modifies lipids and reduces platelet aggregability in haemodialysis patients.

Epoprostenol during haemodialysis.