Beyond the Mediterranean Diet: The Role of Omega-3 Fatty Acids in the Prevention of Coronary Heart Disease

Charles R. Harper, MD, Terry A. Jacobson, MD


Prev Cardiol. 2003;6(3) 

In This Article

Dietary Sources of N-3 Fatty Acids

One challenge facing clinicians is recommending palatable sources of ALA, EPA, and DHA. The nationwide Food Consumption Survey[43] suggests that Americans currently get the bulk of their n-3 PUFA from three key food groups: 1) meat, poultry, and fish; 2) vegetable oils and salad dressings; 3) grain products. Certain species of cold water fish such as halibut, mackerel, herring, and salmon are good sources of EPA and DHA ( Table IV ).[44] Plant sources of n-3 PUFA include some legumes, such as soy and pinto beans, along with nuts and seeds, especially walnuts and flaxseed. Other plant sources include vegetables such as leeks and purslane ( Table V ).[45] Purslane is well known to the Mediterranean diet, but it is not typically consumed in the US diet. Purslane is a leafy green vegetable that grows in all 50 states and is unique because it is rich in ALA and is one of the few plants known to be a source of EPA.[45] Additionally, various oils rich in ALA can be included in the diet as replacements for other fats. A common oil known to be very high in ALA is canola oil, while flaxseed oil has the highest known concentrations of ALA (58%) ( Table VI ).[45] These oils could be substituted for other current sources of dietary fats, such as those fats rich in saturated and transunsaturated fatty acids.

Finally, a variety of marine n-3 PUFA supplements are available to the consumer who cannot tolerate fish or increase their fish consumption. Supplements derived from marine oils contain various amounts of EPA and DHA ( Table VII ).[45] For those concerned about the possible mercury contamination of fish, a vegetarian source of DHA derived from algae is also now available. Cod liver oil has also been touted as a good source of EPA and DHA; however, caution should be used because this oil also contains high levels of vitamin and A and D.


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