Mercury, Fish Oils, and the Risk of Myocardial Infarction

It has been suggested that mercury, a highly reactive heavy metal with no known physiologic activity, increases the risk of cardiovascular disease. Because fish intake is a major source of exposure to mercury, the mercury content of fish may counteract the beneficial effects of its n-3 fatty acids.

In a case-control study conducted in eight European countries and Israel, we evaluated the joint association of mercury levels in toenail clippings and docosahexaenoic acid (C22:6n-3, or DHA) levels in adipose tissue with the risk of a first myocardial infarction among men. The patients were 684 men with a first diagnosis of myocardial infarction. The controls were 724 men selected to be representative of the same populations.