Based on similarities between milk and blood coagulation (Jollès 1975, Jollès et al. 1978, Jollès and Henschen 1982) and the functional similarities between the fibrinogen γ-chain and -casein or its glycomacropeptide segment, the effects of proteins on coagulation factors have been widely investigated (Mazoyer et al. 1992; review by Rutherfurd and Gill 2000). The level of dietary protein modifies platelet aggregation, which is increased in rats consuming a low-protein diet (10% casein) in comparison to a control group (20% casein) and a group on a high-protein diet (60% casein). The production of thromboxane A2 is lower and prostaglandins I2 higher in the low-protein group (Morita et al. 1985).