Prostaglandin E metabolite excretion in normolipidemic subjects is lowered by a moderate reduction of n-6/n-3 polyunsaturate ratio and total fat intake

Abstract

In a longitudinal study consisting of two periods, 22 volunteers consumed controlled diets prepared from commonly available foods. During period 1 (six weeks) all subjects received a baseline diet in which the lipid profile approximated that of the prevailing American diet. During period 2 (24 weeks) they consumed (11 in each group) one of two low-fat, low-cholesterol, low-saturated fatty acid diets based on National Cholesterol Education Panel (NCEP)-Step 2 recommendations: saturated fatty acids 4.0–4.5 en%, monounsaturated fatty acids 10.8–11.6 en%, polyunsaturated fatty acids 10.3–10.5 en%, 45–61 mg of cholesterol/1000 kcal. One of the NCEP-Step 2 diets (high-fish) contained 0.54 en% from fish-derived eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids; the other diet (low-fish) contained 0.13 en% from fish-derived EPA+DHA. The high-fish diet was associated with an average 27% reduction in prostaglandin E metabolite (PGE-M) excretion in comparison to the baseline diet (p=0.01). The low-fish diet too lowered the PGE-M daily output, but the reduction did not reach statistical significance. This is the first report of a significant alteration of prostaglandin metabolism through a moderate lowering of the n-6/n-3 ratio.