The low prevalences of CHD, psoriasis, asthma and rheumatoid arthritis in Eskimos have been attribute to the high dietary intake of EPA from fish and marine mammals. However, even on a Western diet, Eskimos have plasma arachidonic acid (AA) levels far below those seen in Europeans while dihomogammalinolenic acid (DGLA) levels are higher in Eskimos. These low AA and high DGLA levels seem to be due to a genetic abnormality in EFA desaturation since they are found even when EPA intakes are low. Since AA is known to be important in the pathogenesis of CHD, asthma, psoriasis and arthritis, while DGLA has properties which make it of likely therapeutic value in these conditions, the genetically high DGLA and low AA are likely to be as important as dietary EPA in determining Eskimo disease patterns.