Effect of fish diet versus meat diet on blood lipids, coagulation and fibrinolysis in healthy young men.

Twelve healthy young men followed a 10-d controlled diet that included 210 g of fatty fish d-1. The diet was repeated after 18 d, but with lean meat substituted for fish. Blood samples were collected for assessment of serum lipids and haemostatic variables in the plasma. Both experimental diets caused serum triglycerides and plasma factor VIIc to decline to the same extent. The meat diet was also associated with significant changes in plasma levels of tissue plasminogen activator (t-PA) antigen. PA inhibitor type I (PAI-1) antigen, PAI activity, and t-PA activity of the euglobulin fraction of plasma. The fish diet left these variables unchanged from initial values. Thus, in a paired comparison of the two diets, the fish diet was associated with higher levels of t-PA antigen (5.4 vs. 4.7 g ml-1), which is considered to be beneficial with regard to prevention of cardiovascular disease. However, the fish diet was concurrently associated with the putative unfavourable higher levels of PAI-1 antigen (3.0 vs. 1.2 ng ml-1) and PAI activity (6.1 vs. 3.2 IU ml-1), and lower t-PA activity (80 vs. 140 mIU ml-1). Thus it is unclear which of the two diets has the greatest potential in the prevention of cardiovascular disease.