Fish and cardiovascular health

Abstract

The antiatherogenic and antithrombotic effects of fish-oil-derived n-3 (omega-3) polyunsaturated fatty acids have given these compounds a dominating role in explaining the tentatively beneficial effects of fish, e.g. in the prevention of cardiovascular disease (CVD). As a result, the words ‘‘omega-3’’ and ‘‘fish’’ are often lumped together in both experimental studies and reviews. There are, however, strong reasons for separating fish lipids from whole fish muscle. The fish muscle matrix is highly complex, and many other compounds therein have been suggested as bioactive. This review summarizes data from epidemiological and intervention studies addressing effects of fish consumption per se on CVD. Potential roles of fish in CVD protection, and some risks connected to excessive fish eating, i.e. biocides and oxidation, are also discussed. Twelve out of 18 prospective cohort studies, two out of two case_/control studies and two out of three ecological studies indicated reduced coronary mortality among subpopulations eating more fish, often at low fish intakes. Two cohort studies indicated increased risk for cardiovascular mortality. Out of 16 epidemiological studies in total, six prospective cohort studies, two case_/control studies and one ecological study indicated a reduced risk of coronary morbidity with higher fish consumption, and one cohort study indicated an elevated risk of coronary morbidity. Two intervention studies on men with coronary heart disease produced different results, one indicating decreased total mortality, with lower coronary morbidity, but the other indicating an elevated risk for coronary mortality without affecting total morbidity. Thus, ample epidemiological data favour fish intake for reducing mortality and morbidity in cardiovascular disease, although evidence from intervention studies is inconsistent. Among risk factors for CVD that have been proven to be affected by a fish-containing diet are high-density lipoprotein cholesterol, serum triglycerides and blood clotting, the former increasing and the latter two decreasing. Keywords: cardiovascular; coronary health; diet; fish; n-3 PUFA