SIMPLE RELATIONSHIPS EXIST BETWEEN DIETARY LINOLEATE AND THE N-6 FATTY-ACIDS OF HUMAN NEUTROPHILS AND PLASMA

Eicosanoids, the enzymatically oxygenated products of arachidonic acid (AA), appear to be overproduced in some disorders of inflammation. Dietary strategies for decreasing tissue AA require information on the relationships between dietary linoleic acid (LA) and tissue concentrations of AA. The use of either high- or low-LA spreads and cooking oils by healthy male volunteers resulted in a range of LA intakes of 2.5-17.5% of energy, as estimated by diet-diary analysis. Analysis of LA and AA concentrations in neutrophils and plasma lipid fractions from these subjects indicated that there were positive linear relationships between dietary LA and the LA concentrations in neutrophil phospholipids, plasma triglycerides, and plasma cholesteryl esters. By contrast, differences in dietary LA within a broad range were not associated with differences in concentrations of AA in these same neutrophil and plasma fractions. AA concentrations were decreased by supplementation of the diet with 4 g fish oil (1.6 g eicosapentaenoic acid, 0.3 g docosahexaenoic acid). The results suggest that the LA content of tissue lipids may be used to estimate LA intake, and the reduction of dietary LA by using standard dietary strategies is not likely to lead to reduction in tissue AA whereas this can be accomplished by fish-oil supplementation.