THE EFFECT OF DIETARY ARACHIDONIC-ACID ON PLATELET-FUNCTION, PLATELETFATTY-ACID COMPOSITION, AND BLOOD-COAGULATION IN HUMANS

Arachidonic acid (AA) is the precursor of thromboxane and prostacyclin , two of the most active compounds related to platelet function. The e ffect of dietary AA on platelet function in humans is not understood a lthough a previous study suggested dietary AA might have adverse physi ological consequences on platelet function. Here normal healthy male v olunteers (n = 10) were fed diets containing 1.7 g/d of AA for 50 d. T he control diet contained 210 mg/d of AA. Platelet aggregation in the platelet-rich plasma was determined using ADP, collagen, and AA. No st atistical differences could be detected between the aggregation before and after consuming the high-AA diet. The prothrombin time, partial t hromboplastin time, and the antithrombin III levels in the subjects we re determined also. There were no statistically significant difference s in these three parameters when the values were compared before and a fter they consumed the high-AA diet. The in vivo bleeding times also d id not Show a significant difference before and after the subjects con sumed the high-AA diet. Platelets exhibited only small changes in thei r AA content during the AA feeding period. The results from this study on blood clotting parameters and in vitro platelet aggregation sugges t that adding 1.5 g/d of dietary AA for 50 d to a typical Western diet containing about 200 mg of AA produces no observable physiological ch anges in blood coagulation and thrombotic tendencies in healthy, adult males compared to the unsupplemented diet. Thus, moderate intakes of foods high in AA have few effects on blood coagulation, platelet funct ion, or platelet fatty acid composition.