PILTHOVEN, THE NETHERLANDS. Several studies have found a correlation between fish consumption and death from coronary heart disease (CHD). By far the majority of the studies concluded that fish consumption reduces the risk of dying from CHD, but a few found no such effect and one even found a negative effect. A team of researchers from Finland, Italy, and the Netherlands believes they have found the reason for the differing results.
Fatty fish Offer Greater Benefits than Lean Fish
Their study involved 2738 men who were aged 50 to 69 years at the start of the study in 1970. After 20 years of follow-up 242 (22.2%) of the Finnish men, 116 (10.6%) of the Italian men, and 105 (19%) of the Dutch men had died from CHD. The researchers found no correlation between total fish consumption and CHD mortality. They also failed to confirm a correlation between the consumption of lean fish (plaice, codfish, bream, perch, pike) and the risk of dying from CHD. However, when looking at the consumption of fatty fish (mackerel, herring, eel) the researchers found a clear protective effect. Men who habitually consumed fatty fish had a 34% lower risk of dying from CHD than did men who did not eat fatty fish. This correlation held true even after adjusting for other variables commonly associated with an increased risk of death from CHD.
The researchers point out that while 15 grams of lean fish provides only about 50 mg of omega-3 fatty acids, 15 grams of fatty fish provides about 400 mg. They suggest that the oils in fatty fish (eicosapentaenoic acid and docosahexaenoic acid) prevent death from CHD through their inhibition of platelet aggregation, their antiarrhythmic properties, and their tendency to increase heart rate variability. The researchers believe that the reason why one study found a higher mortality from CHD among Finnish men consuming lean fish was that the fish from the area under study was heavily contaminated with mercury.
Oomen, Claudia M., et al. Fish consumption and coronary heart disease mortality in Finland, Italy, and the Netherlands. American Journal of Epidemiology, Vol. 151, May 15, 2000, pp. 999-1006