Vitamin E concentrations in human blood plasma and platelets.

Vitamin E (tocopherol), cholesterol, triglyceride, and total lipid concentrations were determined in the plasma of 49 healthy, human, male subjects ranging in age from 24 to 91 yr. Tocopherol concentrations in the blood platelets of these subjects were also determined. alpha and gamma tocopherol accounted for nearly all of the vitamin E compounds in plasma and platelet samples. The mean gamma tocopherol concentration was one-fourth of that of alpha in both plasma and platelets. The alpha and gamma tocopherol concentrations in plasma showed statistically significant positive correlations with total lipid, cholesterol, and triglyceride concentrations. However, the platelet alpha and gamma tocopherol concentrations were not significantly correlated with plasma lipid, cholesterol, or triglyceride concentrations. Thus platelet vitamin E concentrations do not passively reflect plasma lipid changes and are postulated to be better indicators of vitamin E nutritional status than plasma tocopherol concentrations.