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Absorption and retinol equivalence of β-carotene in humans is influenced by dietary vitamin A intake
- Source :
- Journal of Lipid Research, Vol 44, Iss 8, Pp 1591-1600 (2003)
- Publication Year :
- 2003
- Publisher :
- Elsevier, 2003.
-
Abstract
- The effect of vitamin A supplements on metabolic behavior of an oral tracer dose of [14C]β-carotene was investigated in a longitudinal test-retest design in two adults. For the test, each subject ingested 1 nmol of [14C]β-carotene (100 nCi) in an emulsified olive oil-banana drink. Total urine and stool were collected for up to 30 days; concentration-time patterns of [14C]β-carotene, [14C]retinyl esters, and [14C]retinol were determined for 46 days. On Day 53, the subjects were placed on a daily vitamin A supplement (10,000 IU/day), and a second dose of [14C]β-carotene (retest) was given on Day 74. All 14C determinations were made using accelerator mass spectrometry. In both subjects, the vitamin A supplementation was associated with three main effects: 1) increased apparent absorption: test versus retest values rose from 57% to 74% (Subject 1) and from 52% to 75% (Subject 2); 2) an ∼10-fold reduction in urinary excretion; and 3) a lower ratio of labeled retinyl ester/β-carotene concentrations in the absorptive phase. The molar vitamin A value of the dose for the test was 0.62 mol (Subject 1) and 0.54 mol (Subject 2) vitamin A to 1 mol β-carotene. Respective values for the retest were 0.85 and 0.74.These results show that while less cleavage of β-carotene occurred due to vitamin A supplementation, higher absorption resulted in larger molar vitamin A values.
- Subjects :
- accelerator mass spectrometry
isotope
kinetic
Biochemistry
QD415-436
Subjects
Details
- Language :
- English
- ISSN :
- 00222275
- Volume :
- 44
- Issue :
- 8
- Database :
- Directory of Open Access Journals
- Journal :
- Journal of Lipid Research
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.27ddc422992d4cbf9db7b7762290c7ab
- Document Type :
- article
- Full Text :
- https://doi.org/10.1194/jlr.M300116-JLR200