Effect of supplemental beta-carotene on plasma concentrations of carotenoids, retinol, and alpha-tocopherol in humans

Am J Clin Nutr. 1998 Sep;68(3):642-7. doi: 10.1093/ajcn/68.3.642.


High doses of beta-carotene, a lipid-soluble nutrient, may affect the plasma concentrations of other lipid-soluble nutrients. The purpose of this study was to assess the effects of long-term daily supplementation with beta-carotene (50 mg/d) on circulating concentrations of other carotenoids, retinol, and alpha-tocopherol over time. Data were available from 259 men and women participating in the Carotene Prevention Trial, a 2-center chemoprevention trial designed to determine whether supplemental beta-carotene can prevent second malignant tumors in patients cured of an early stage cancer of the oral cavity, pharynx, or larynx. Up to 2 blood samples were obtained before the intervention (before and after a 1-mo placebo run-in), with postrandomization samples obtained at 3, 12, 24, 36, 48, and 60 mo. Supplementation with beta-carotene produced a persistent 9- to 10-fold increase in median plasma beta-carotene concentrations (225 nmol/L at baseline to 2255 nmol/L at 3 mo) and a persistent 2-fold increase in median plasma alpha-carotene concentrations (45 nmol/L at baseline to 95 nmol/L at 3 mo). Concentrations of retinol, alpha-tocopherol, lycopene, and lutein/zeaxanthin were not affected by supplemental beta-carotene. Up to 5 y of daily supplementation with beta-carotene increased circulating concentrations of alpha- and beta-carotene, but did not alter concentrations of lycopene, lutein/zeaxanthin, retinol, or alpha-tocopherol.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carotenoids / blood*
  • Dietary Supplements*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / prevention & control
  • Vitamin A / blood*
  • Vitamin E / blood*
  • beta Carotene / administration & dosage*
  • beta Carotene / therapeutic use


  • beta Carotene
  • Vitamin A
  • Vitamin E
  • Carotenoids