Comparison of plasma α and γ tocopherol levels following chronic oral administration of either all-rac-α-tocopheryl acetate or RRR-α-tocopheryl acetate in normal adult male subjects

Open Access
Publisher Website
Google Scholar
Abstract
Vitamin E was administered orally (400 IU twice a day) to adult male humans for 28 days as either dl-α-tocopheryl acetate (all-rac-α-tocopheryl acetate) or d-α-tocopheryl acetate (RRR-α-tocopheryl acetate). Plasma α-tocopherol rose rapidly and fell at the same rate following cessation of supplementation with both forms of vitamin E. No significant differences in plasma α- or γ-tocopherol levels were found between the two forms of vitamin E following their administration. The results confirm the currently accepted biopotencies of 1.0 IU/mg and 1.36 IU/mg, respectively for the two forms of vitamin E. Supplementation with either form of α-tocopheryl acetate resulted in depressing plasma γ-tocopherol to <⅓ of initial levels; also the γ/α ratio was depressed to less than 1/7 of the initial value. The study suggests that the γ/α vitamin E ratio might also serve as a sensitive index of α-tocopherol ingestion.