INGESTION OF MARINE OIL REDUCES EXCRETION OF 11-DEHYDROTHROMBOXANE -B(2), AN INDEX OF INTRAVASCULAR PRODUCTION OF THROMBOXANE -A(2)

We evaluated the effect of anchovy oil supplementation on the endogenous production of thromboxane A2 by measuring the excretion of its stable metabolite, 11-dehydrothromboxane B2 (11-DTXB2), in 24-h urine. In a longitudinal study, 35 male volunteers consumed a controlled basal diet for two experimental periods lasting a total of 20 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 x 1 g/d) consisting of a blend of fats approaching the fatty acid profile of the basal diet. During period 2 the subjects received 15 x 1 g/d capsules of fish oil concentrate (FOC). PO and FOC capsules contained 1 mg alpha-tocopherol per gram of fat as antioxidant. A 38% reduction of 11-DTXB, excretion was observed after 10 weeks of FOC supplementation (period 2, n-6/n-3 PUFA ratio = 2.3), compared to an identical period of PO supplementation (period 1, n-6/n-3 = 12.5), p = 0.0001. The 11-DTXB2 excretion reduction (DELTA) fits the quadratic equation DELTA = 136.0038 - 0.3178(tx1) - 0.0002(tx1)2, (R2 =0.8944), where tx1 is the excretion rate at the end of period 1. This finding supports the hypothesis that the antithrombotic effect of marine oil is mediated, at least in part, by diet-induced shifts in the eicosanoid system.