Effect of supplemental β-carotene on plasma concentrations of carotenoids, retinol, and α-tocopherol in humans

Abstract

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.

Circulating levels of retinol, tocopherol and carotenoid in Nepali pregnant and postpartum women following long-term β-carotene and vitamin A supplementation

“…The circulating lutein zeaxanthin level in this Nepali population was similar (Ribaya-Mercado et al, 1995;Rock et al, 1995) or higher (Ascherio et al, 1992;Forman et al, 1996;Can®eld et al, 1997Can®eld et al, ,1998Mayne et al, 1998) than reported among American adults. This comparability, between a markedly malnourished population in Nepal and wellnourished groups in the United States, is unexplainable.…”

“…The b-cryptoxanthin level in our pregnant women was similar to those reported in Malawian pregnant women (Lan et al, 1999), but lower than seen in American populations (Forman et al, 1996;Can®eld et al, 1997Can®eld et al, ,1998Rock et al, 1995). Circulating a-tocopherol levels were 45 ± 75% lower in our population than in well-nourished lactating women or other healthy American men or women (Ascherio et al, 1992;Mayne et al, 1998;Ribaya-Mercado et al, 1995).…”

“…These ®ndings contrast with mixed results from trials in well-nourished populations. A recent study by Mayne et al (1998) reported that up to 60 months of b-carotene supplementation (50 mgaday) did not affect serum retinol, a-tocopherol, lycopene and lutein zeaxanthin concentrations. The serum a-carotene level was increased 2-fold after supplementation, but the authors suggested that this might have been due to contamination of capsules with a-carotene (Mayne et al, 1998).…”

“…A recent study by Mayne et al (1998) reported that up to 60 months of b-carotene supplementation (50 mgaday) did not affect serum retinol, a-tocopherol, lycopene and lutein zeaxanthin concentrations. The serum a-carotene level was increased 2-fold after supplementation, but the authors suggested that this might have been due to contamination of capsules with a-carotene (Mayne et al, 1998). Wahlqvist et al (1994) observed an increase in serum b-carotene, lycopene, and a-carotene following b-carotene supplementation (20 mgaday) for 2 y.…”

Increases in Plasma Carotenoid Concentrations in Response to a Major Dietary Change in the Women's Healthy Eating and Living Study

“…It is important to compare the carotenoid increases achieved in this study with increases achieved with dietary h-carotene supplementation studies. Mayne et al (37) reported on the effect of daily administration of one capsule containing 50 mg h-carotene in patients with a history of cancers of the oral cavity, pharynx, or larynx. The first difference of note between this study and the WHEL Study relates to baseline h-carotene concentrations.…”