Human vitamin E requirements assessed with the use of apples fortified with deuterium-labeled alpha-tocopheryl acetate

Am J Clin Nutr. 2006 Feb;83(2):299-304. doi: 10.1093/ajcn/83.2.299.


Background: Little is known about factors that modulate dietary alpha-tocopherol bioavailability.

Objectives: The study aimed to assess the efficacy of vitamin E-fortified apples as a low-fat vitamin E delivery system, the influence of fat on vitamin E absorption, and human vitamin E requirements by using plasma alpha-tocopherol kinetics at a dosage of alpha-tocopherol found in food.

Design: Apples fortified with deuterium-labeled alpha-tocopheryl acetate were consumed by 5 participants at a breakfast containing 0%, 6%, or 21% kcal from fat in 3 sequential trials. The trials were separated by a 2-wk washout period. Blood samples were obtained up to 72 h, and plasma was analyzed for labeled and unlabeled alpha-tocopherol.

Results: Compared with observations in the 0% fat trial, the maximum observed plasma d6-alpha-tocopherol concentrations (Cmax) and the areas under the curve increased 2- and 3-fold during the 6% and 21% fat trials, respectively. The mean (+/-SD) estimated percentage d6-alpha-tocopherol absorbed increased from 10 +/- 4% during the 0% fat trial to 20 +/- 3% and 33 +/- 5% during the 6% and 21% fat trials, respectively. The mean time to Cmax (9 +/- 2 h), fractional disappearance rates (0.022 +/- 0.003 pools/d), and half-lives (32 +/- 4 h) did not differ significantly between the trials. With the use of fractional disappearance rates and baseline plasma alpha-tocopherol concentrations, the estimated daily plasma alpha-tocopherol efflux was 13-14 mg. The estimated rate of alpha-tocopherol delivery to tissues was 5 mg/d.

Conclusions: Given an estimated 33% absorption, the amount of dietary vitamin E needed daily to replace irreversible losses is </=15 mg. These estimates support the current human vitamin E requirements despite the claims that the median amount of vitamin E that Americans consume is 7 mg/d.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Antioxidants / pharmacokinetics*
  • Area Under Curve
  • Biological Availability
  • Cross-Over Studies
  • Deuterium
  • Dietary Fats / pharmacology*
  • Dose-Response Relationship, Drug
  • Female
  • Food, Fortified*
  • Humans
  • Intestinal Absorption / drug effects
  • Male
  • Malus*
  • Nutritional Requirements
  • Tocopherols
  • Vitamin E / blood
  • Vitamin E / pharmacokinetics*
  • alpha-Tocopherol / analogs & derivatives
  • alpha-Tocopherol / pharmacokinetics


  • Antioxidants
  • Dietary Fats
  • Vitamin E
  • Deuterium
  • alpha-Tocopherol
  • Tocopherols