The effect of long-term beta-carotene and vitamin A administration on serum concentrations of alpha-tocopherol
Many micronutrients are currently being tested for cancer prevention activity. A short-term study recently suggested that two of these nutrients, beta-carotene and alpha-tocopherol, may have an adverse interaction, with beta-carotene supplementation leading to markedly decreased serum concentrations...
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Published in | Cancer epidemiology, biomarkers & prevention Vol. 3; no. 5; p. 429 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
American Association for Cancer Research
01.07.1994
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Subjects | |
Online Access | Get full text |
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Summary: | Many micronutrients are currently being tested for cancer prevention activity. A short-term study recently suggested that
two of these nutrients, beta-carotene and alpha-tocopherol, may have an adverse interaction, with beta-carotene supplementation
leading to markedly decreased serum concentrations of alpha-tocopherol. We have analyzed the effect of beta-carotene supplementation
on serum concentrations of alpha-tocopherol in 2319 participants enrolled in the Carotene and Retinol Efficacy Trial who have
taken beta-carotene and vitamin A for up to 6 years. One thousand thirty-five participants enrolled in two pilot trials to
the Carotene and Retinol Efficacy Trial had serum collected at yearly intervals; an additional 1284 recently recruited participants
had serum collected at biennial intervals. Using standard high pressure liquid chromatography techniques, with attention to
quality control, these samples were analyzed for beta-carotene and alpha-tocopherol. After up to 6 years of supplementation
with beta-carotene (30 mg/day) and vitamin A (25,000 international units/day) we found a small but statistically significant
increase in the serum concentration of alpha-tocopherol in participants taking the active agents. No evidence of a decrease
was found in any of the subpopulations examined. We conclude that long-term supplementation with the combination of beta-carotene
and vitamin A does not decrease serum concentrations of alpha-tocopherol. Our long-term trial validates results from several
shorter trials conducted by others. The concept of adverse interactions between supplemental micronutrients is important.
All cancer prevention trials should closely monitor serum concentrations of micronutrients, as well as the incidence of other
significant disease. |
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ISSN: | 1055-9965 1538-7755 |