Sex differences in the inhibition of γ-tocopherol metabolism by a single dose of dietary sesame oil in healthy subjects

Background: γ-Tocopherol has unique properties that may be beneficial in sustaining optimal human health, but hepatic vitamin E metabolism enhances γ-tocopherol turnover. Objective: Our aim was to determine the extent to which dietary sesame lignans alter human α- and γ-tocopherol metabolism and elimination as carboxyethyl hydroxychromanols (CEHCs). Design: Healthy participants (n = 5 women and 5 men) in a randomized, crossover study (with 4-wk washout) consumed muffins prepared with either corn oil or unrefined sesame oil (sesamin, 94 mg; sesamolin, 42 mg), along with a capsule containing a 1:1 molar ratio of deuterium-labeled d₆-α- and d ₂-γ-tocopherol acetates (≈50 mg each). Plasma and urine were collected up to 72 h; unlabeled and labeled tocopherol and CEHC concentrations were determined by liquid chromatography-mass spectrometry. Results: Sesame oil muffin consumption in men, but not in women, decreased (P < 0.05) areas under plasma d₂-γCEHC concentration-time curves (area under the curve) and maximum concentrations. However, in both sexes urinary d ₂-γ-CEHCs were decreased for 24 h following sesame oil muffin consumption. Conclusions: In humans, γ-tocopherol metabolism can be inhibited by the simultaneous consumption of γ-tocopherol and sesame lignans. The observed differences between men and women with respect to vitamin E metabolism warrant further investigation.