Essential fatty acids and dietary stress.

There are two families of essential fatty acids that must be obtained from the diet: the omega-6 fatty acids consisting of linoleic and arachidonic acids and the omega-3 fatty acids consisting of linolenic, eicosapentaenoic and docosahexaenoic acids (Prog Chem Fats Other Lipids 1968:9;275-348; Recent Pat Cardiovasc Drug Discov 2007; 2:13-21; Mini Rev Med Chem 2008; 8:107-115). Vegetables and vegetable oils are sources of linoleic and linolenic acids, and the higher omega-3s are obtained from fish. The estimated ratio of omega-6:omega-3 fatty acids in the typical Western diet is about 20:1, whereas, several lines of evidence indicate that a ration of 1:1 would be optimal. Both series of fatty acids can be oxidatively metabolized to a range of products. The oxidative metabolites of arachidonic acid are all proinflammatory and/or prothrombotic, while the corresponding omega-3 metabolites are anti-inflammatory and/or antithrombotic. The imbalanced consumption of the two families of essential fatty acids contributes to a range of diseases. Greater awareness of this problem is leading to increased use of dietary supplements and new products intended to decrease omega-6 consumption while increasing omega-3 intake.