Fish consumption and coronary heart disease mortality. A systematic review of prospective cohort studies

To review all prospective cohort studies examining the relationship between fish intake and coronary heart disease mortality, and to assess the strength and consistency of their findings.

Systematic review of studies based on individual records of fish or n-3 polyunsaturated fatty acid consumption and coronary heart disease death. Studies were given scientific quality scores and divided into categories of high, intermediate, or insufficient quality.

Coronary heart disease mortality.

Eleven studies were identified. The cohorts counted a total of 116764 individuals. Of four studies judged to be of high quality, the two largest (n = 44895 and 20051) were performed in populations at low risk of coronary heart disease. They found no protective effect of fish consumption. The other two high-quality studies were relatively small (n = 852 and 1822) and included individuals at higher risk. They both found an inverse relationship between fish consumption and coronary heart disease death, suggesting that 40-60 g fish per day is optimal and associated with a risk reduction of 40-60%. Results of four studies of intermediate quality support that fish consumption is inversely associated with coronary heart disease mortality in high-risk populations only. Three studies were judged to be of insufficient quality to be used for drawing conclusions.

Fish consumption is not associated with reduced coronary heart disease mortality in low-risk populations. However, fish consumption at 40-60 g daily is associated with markedly reduced coronary heart disease mortality in high-risk populations. The underlying biochemical mechanism is not known and causal inference premature.