The cardioprotective benefits of the 'Mediterranean' diet and its reduction of mortality are strikingly evident in the results of studies such as the DART study (32) and the Lyon Diet Heart Study (33). The results of these studies are not solely due to the regular inclusion of oily fish, but this did have a key role. Oily fish such as mackerel, herring, sardines, trout and salmon are a rich source of the n-3 polyunsaturates. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the long-chain omega-3 PUFAs, are thought to be beneficial due to their anti-thrombolytic and anti-inflammatory action as well as their triglyceride-lowering effects. The UK Department of Health has recommended to the general population that they consume two portions of fish (100 g or 3-4 oz portion) a week, one of which should be oily (34). People with diabetes should be encouraged to include oily fish in the diet, ideally two to three times a week (35). Fish oils are increasingly available in capsule or liquid form. These should provide approximately 0.5-1.0 g of n-3 fatty acids per day. Vegetarians, or those allergic to fish, can optimise their n-3 intakes by using vegetable n-3 sources (rapeseed, canola, linseed and flax oils), but the conversion rate is low and other polyunsaturates can compete.
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