The first indication of the benefits associated with omega-3 fatty acids came from studies conducted among the Inuit of Greenland who, despite a diet almost exclusively based on the consumption of sea animal meat, are surprisingly unaffected by heart disease. The animals in their diet, and most fatty fish such as salmon, sardines, and mackerel, contain large amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two long-chain omega-3 fatty acids that play a major role in the prevention of certain coronary diseases.
Other major consumers of fish, such as the Japanese, who absorb on average almost 1 g of EPA and DHA a day, have a coronary disease mortality rate almost 90 percent lower than that of inhabitants of regions where little fish is eaten such as in North America. The protective effects of these fats can even be observed in less significant quantities: Modest consumption of about 250 to 500 mg of EPA and DHA a day—barely equivalent to a half-portion (3.5 ounces) of salmon—reduces the risk of mortality due to coronary disease by about 40 percent.
And this positive effect sets in quickly: Studies have shown that regular consumption of fatty fish causes positive effects on the heart within weeks by reducing episodes of arrhythmia, a pathology often responsible for sudden death.