Physiological Factors Influencing Vitamin E Biokinetics

doi:10.1196/annals.1331.006

Limited information is available on factors that can influencevitamin E bioavailability. In several studies we have investigatedthe influence of dietary, biochemical, and genetic factors onvitamin E biokinetics. In these studies, subjects ingested acapsule containing 150 mg deuterated RRR- ${alpha}$ -tocopheryl acetate,blood was taken up to 48 hr, and tocopherols were analyzed byliquid chromatography and mass spectroscopy. There was significantlygreater plasma-labeled ${alpha}$ -tocopherol concentrations when the capsulewas consumed with a high-fat meal (17.5 g) versus a low-fatmeal (2.7 g), and there was also a difference between a high-fattoast and butter and a cereal with full-fat milk meal (both17.5 g fat), indicating that both the amount of fat and foodmatrix is important for vitamin E absorption. Dyslipidemic subjectsdisplayed a reduced plasma uptake of newly absorbed ${alpha}$ -tocopherol,and differences were also apparent in individual lipoproteins.A decreased uptake of labeled ${alpha}$ -tocopherol was also observedin erythrocytes, platelets, and lymphocytes of dyslipidemics.Following vitamin E supplementation (400 mg/day, 4 weeks), theuptake of newly absorbed ${alpha}$ -tocopherol was decreased, presumablybecause of saturation of ${alpha}$ -tocopherol transfer protein. We alsofound that apoE3 subjects displayed a considerably reduced uptakeof newly absorbed labeled ${alpha}$ -tocopherol compared to apoE4 subjects,which may be a consequence of the reduced low-density lipoproteincatabolic rate in these subjects. Taken together, these datashow that several physiological factors influence the uptakeof newly absorbed ${alpha}$ -tocopherol, and that this is an importantconsideration in the design of future vitamin E supplementationstudies.

				X. Gao, A. Martin, H. Lin, O. I. Bermudez, and K. L. Tucker {alpha}-Tocopherol Intake and Plasma Concentration of Hispanic and Non-Hispanic White Elders Is Associated with Dietary Intake Pattern J. Nutr., October 1, 2006; 136(10): 2574 - 2579. [Abstract] [Full Text] [PDF]