Stearic acid, clotting, and thrombosis.

Stearic acid causes hypercoagulability of the blood by activation of factor XII and by aggregation of blood platelets. Injection of unbound stearic acid (sodium salt) into the systemic circulation of dogs was followed by massive generalized thrombosis and sudden death. Similar infusions into birds, which are deficient in factor XII, did not cause hypercoagulability or thrombosis. The effects of the long-chain saturated fatty acids could be prevented by using albumin to bind the stearic acid at a molar ratio of free fatty acid (FFA) to albumin of < 2. The major issue is whether eating foods rich in stearic acid can cause a thrombogenic effect. We have no experimental evidence to support this concept. If a thrombogenic effect of long-chain saturated fatty acids exists in humans, it is most likely to occur as an aberration of fatty acid transport in which the FFA-albumin molar ratio exceeds 2 either as a result of very high plasma FFA concentrations from lipid mobilization or a low concentration of albumin in the blood as found in disease states such as the nephrotic syndrome.