MONOUNSATURATED FATTY ACID-ENRICHED DIET DECREASES PLASMA PLASMINOGEN-ACTIVATOR INHIBITOR TYPE-1

An increase in levels of plasma plasminogen activator inhibitor type 1 (PAI-1) is one of the main hemostatic alterations in patients with co ronary heart disease. Despite growing interest in the fibrinolytic sys tem, few studies have been undertaken to determine the effect exerted on it by the different dietary fatty acids. We investigated the effect of a monounsaturated fat (MUFA)-rich diet in comparison with a low-fa t diet (National Cholesterol Education Program step 1 diet) (NCEP-1) o n factors involved in blood coagulation and fibrinolysis. We also dete rmined the effect of dietary cholesterol on these blood parameters. Tw enty-one young, male: healthy volunteers followed two low-fat/high-car bohydrate diets (<30% fat, <10% saturated fat, 14% MUFA) for 24 days e ach, with 115 or 280 mg of cholesterol per 1000 kcal per day, and two oleic acid-enriched diets (38% fat, 24% MUFA) with the same dietary ch olesterol as the low-fat/high-carbohydrate diets. Plasma levels of fib rinogen, thrombin-antithrombin complexes, prothrombin fragments 1+2, p lasminogen, ct, antiplasmin, and tissue plasminogen activator were not significantly different among the experimental diets used in this stu dy. Consumption of the diet rich in MUFA resulted in a significant dec rease in both PAI-1 plasma activity (P<.005) and antigenic PAI-I (P<.0 4) compared with the carbohydrate-rich diet (NCEP-1). The addition of dietary cholesterol to each of these diets did not result in any signi ficant additional effect, Changes in insulin levels and PAI-1 activity were positively correlated (r=.425; P<.02). In conclusion, consumptio n of diets rich in MUFAs decreases PAI-1 plasma activity, which is acc ompanied by a parallel decrease in plasma insulin levels.