Dietary n-3 fatty acids and arthritis

We have evidence that dietary fish oil (FO) decreases severity of collagen-induced arthritis (CIA), changes the fatty acid composition of macrophage (M phi) membrane phospholipids, decreases M phi synthesis of prostaglandins (PGs), changes chemotactic ability of M phi s, and affects metabolism of acute phase proteins. Gender also has pronounced effects on susceptibility to CIA and M phi prostaglandin profiles. The mechanisms by which dietary n-3 fatty acids may act to alleviate symptoms of CIA, as well as interactions of dietary n-3 and n-6 fatty acids and gender are discussed. We suggest that the ability of FO diets to influence favourably the course of chronic inflammatory diseases is mediated via alterations in n-6 fatty acid metabolism and that intrinsic differences in n-6 fatty acid metabolism may account not only for our reported gender differences in incidence and severity of CIA, but also the well-documented sexual dimorphism in immune/inflammatory responses in general.