In a cross-sectional survey of 86 elderly persons, it was observed that subjects with elevated plasma
alpha-tocopherol levels had depressed plasma
gamma-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-
alpha-tocopherol daily for 8 wk, plasma
gamma-tocopherol and
beta-tocopherol decreased in all subjects.
After supplementation,
gamma-tocopherol values were typically 30-50% of initial values, and
alpha-tocopherol values were typically 200-400% of initial values.
These results suggest that intestinal
uptake and/or plasma
transport make more efficient use of
alpha-tocopherol than of
gamma- or
beta-tocopherol.
Moreover, the results indicate that the ratio of
gamma- to
alpha-tocopherol in plasma would be a more satisfactory index to measure compliance in trials involving supplementation with
alpha-tocopherol.