Oral α-Tocopherol Supplements Decrease Plasma γ-Tocopherol Levels in Humans

Abstract

In a cross-sectional survey of 86 elderly persons, it was observed that subjects with elevated plasma α-tocopherol levels had depressed plasma γ-tocopherol. Tocopherols were measured by both reverse-phase and normal-phase high performance liquid chromatography (HPLC). When eight human volunteers (age range 30–60) were given 1200 IU of all-rac-α-tocopherol daily for 8 wk, plasma γ-tocopherol and β-tocopherol decreased in all subjects. After supplementation, γ-tocopherol values were typically 30–50% of initial values, and α-tocopherol values were typically 200–400% of initial values. These results suggest that intestinal uptake and/or plasma transport make more efficient use of α-tocopherol than of γ- or β-tocopherol. Moreover, the results indicate that the ratio of γ- to α-tocopherol in plasma would be a more satisfactory index to measure compliance in trials involving supplementation with α-tocopherol.