| Autor: |
Shawna L. Lemke, Stephen R. Dueker, Jennifer R. Follett, Yumei Lin, Colleen Carkeet, Bruce A. Buchholz, John S. Vogel, Andrew J. Clifford |
| Jazyk: |
angličtina |
| Rok vydání: |
2003 |
| Předmět: |
|
| Zdroj: |
Journal of Lipid Research, Vol 44, Iss 8, Pp 1591-1600 (2003) |
| Druh dokumentu: |
article |
| ISSN: |
0022-2275 |
| DOI: |
10.1194/jlr.M300116-JLR200 |
| Popis: |
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. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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