QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Proteggente, A. R. Articles by Lodge, J. K. Search for Related Content PubMed PubMed Citation Articles by Proteggente, A. R. Articles by Lodge, J. K.

---

Human Nutrition and Metabolism

Noncompetitive Plasma Biokinetics of Deuterium-Labeled Natural and Synthetic -Tocopherol in Healthy Men with an apoE4 Genotype^1,2

Anna R. Proteggente, Rufus Turner^*, Jonathan Majewicz^*, Gerald Rimbach^*, Anne Marie Minihane^*, Klaus Krämer and John K. Lodge³

Centre for Nutrition and Food Safety, School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK; ^* Hugh Sinclair Human Nutrition Unit, School of Food Biosciences, University of Reading, Reading RG6 6AP, UK; and BASF Aktiengesellschaft, Fine Chemicals, 67056 Ludwigshafen, Germany

³To whom correspondence should be addressed. E-mail: j.lodge{at}surrey.ac.uk.

Previous studies comparing the biokinetics of deuterated natural (RRR) and synthetic (all-rac) -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--tocopheryl and all-rac--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 -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 -tocopherol concentrations (P < 0.001), but decreased the plasma response to newly absorbed deuterated RRR or all-rac -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.

KEY WORDS: • tocopherol • natural • synthetic • biokinetics • bioavailability • apoE4