Noncompetitive plasma biokinetics of deuterium-labeled natural and synthetic alpha-tocopherol in healthy men with an apoE4 genotype

Proteggente, Anna R., Turner, Rufus, Majewicz, Jonathan, Rimbach, Gerald, Minihane, Anne Marie, Krämer, Klaus and Lodge, John K. (2005) Noncompetitive plasma biokinetics of deuterium-labeled natural and synthetic alpha-tocopherol in healthy men with an apoE4 genotype. Journal of Nutrition, 135 (5). pp. 1063-1069. ISSN 0022-3166

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Abstract

Previous studies comparing the biokinetics of deuterated natural (RRR) and synthetic (all-rac) alpha-tocopherol (vitamin E) used a simultaneous ingestion or competitive uptake approach and reported relative bioavailability ratios close to 2:1, higher than the accepted biopotency ratio of 1.36:1. The aim of the current study was to compare the biokinetics of deuterated natural and synthetic vitamin E using a noncompetitive uptake model both before and after vitamin E supplementation in a distinct population. Healthy men (n = 10) carrying the apolipoprotein (apo)E4 genotype completed a randomized crossover study, comprised of two 4-wk treatments with 400 mg/d (RRR-alpha-tocopheryl and all-rac-alpha-tocopheryl acetate) with a 12-wk washout period between treatments. Before and after each treatment period, the subjects consumed a capsule containing 150 mg deuterated alpha-tocopheryl acetate in either the RRR or all-rac form depending on their treatment regimen. Blood was obtained up to 48 h after ingestion, and tocopherols analyzed by LC/MS. After deuterated all-rac administration, plasma deuterated tocopherol maximum concentrations and area under the concentration vs. time curves (AUC) were lower than those following RRR administration. The RRR:all-rac ratios determined from the deuterated biokinetic profiles (maximum concentration; C(max)) and AUCs were 1.35:1 +/- 0.17 and 1.33:1 +/- 0.18, respectively. The 4-wk supplementation with either RRR or all-rac significantly increased plasma alpha-tocopherol concentrations (P < 0.001), but decreased the plasma response to newly absorbed deuterated RRR or all-rac alpha-tocopherol. Using a noncompetitive uptake approach, the relative bioavailability of natural to synthetic vitamin E in apoE4 males was close to the currently accepted biopotency ratio of 1.36:1.

Item Type:	Article
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Groups > Cardiovascular and Metabolic Health Faculty of Medicine and Health Sciences > Research Groups > Nutrition and Preventive Medicine Faculty of Medicine and Health Sciences > Research Centres > Lifespan Health
Depositing User:	Rhiannon Harvey
Date Deposited:	01 Jun 2011 08:17
Last Modified:	06 Feb 2025 03:09
URI:	https://ueaeprints.uea.ac.uk/id/eprint/31646
DOI:	10.1093/jn/135.5.1063

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