| A novel extrinsic reference method for assessing the vitamin A value of plant foods. | |
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MedLine Citation:
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PMID: 11522559 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: The amounts of vitamin A that are metabolically derived from specific carotene-containing foods are largely unknown. OBJECTIVE: We sought to develop an improved method for estimating the metabolic vitamin A potential of provitamin A carotenoids by using [2H4]retinyl acetate (d4-RA) as an extrinsic reference standard. DESIGN: Healthy subjects consumed a standardized test meal containing 6 mg beta-carotene as either raw carrot or spinach, either 20 or 1 g added fat, and 6.0 micromol d4-RA. Concentrations of unlabeled (d0) retinyl esters (RE), labeled (d4) RE, and carotenoids in the plasma triacylglycerol-rich lipoprotein fraction (d < 1.006 kg/L) were determined in serial blood samples with HPLC and gas chromatography-mass spectrometry. Baseline-corrected areas under the curve for d0-RE, d4-RE, and carotenoids were calculated, and the masses of absorbed d0-retinol and carotenes were estimated assuming 80% absorption of the d4-RA reference dose. RESULTS: In trials with ample (20 g) fat (n = 6), 7 +/- 4% of the 6 mg beta-carotene ingested was taken up as beta-carotene plus RE with 0.3 +/- 0.1 mg as retinol. Test meals without carotenes yielded no beta-carotene or d0-RE response and there was no effect of treatment (either fat amount or vegetable, n = 6) on the mean d4-RE area under the curve. The lower-than-expected vitamin A yields were attributed to poor intestinal uptake rather than to low conversion of beta-carotene to RE. CONCLUSION: The triacylglycerol-rich lipoprotein and d4-RA method, which controls for variation in chylomicron kinetics in vivo and RE recovery during analysis, is useful for obtaining quantitative estimates of the vitamin A potential of single meals. |
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Authors:
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A J Edwards; C S You; J E Swanson; R S Parker |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: The American journal of clinical nutrition Volume: 74 ISSN: 0002-9165 ISO Abbreviation: Am. J. Clin. Nutr. Publication Date: 2001 Sep |
Date Detail:
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Created Date: 2001-08-27 Completed Date: 2001-09-27 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0376027 Medline TA: Am J Clin Nutr Country: United States |
Other Details:
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Languages: eng Pagination: 348-55 Citation Subset: AIM; IM |
Affiliation:
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Division of Nutritional Sciences and the Department of Food Science, Cornell University, Ithaca, NY 14853, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Antioxidants / analysis, metabolism, pharmacokinetics Area Under Curve Biological Availability Chromatography, High Pressure Liquid Daucus carota / chemistry Female Gas Chromatography-Mass Spectrometry Humans Intestinal Absorption Isotope Labeling Male Nutritive Value Plants, Edible / chemistry* Reference Standards Spinacia oleracea / chemistry Triglycerides / blood, chemistry Vitamin A / analogs & derivatives, analysis, metabolism, pharmacokinetics* beta Carotene / analysis, metabolism, pharmacokinetics* |
| Chemical | |
Reg. No./Substance:
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0/Antioxidants; 0/Triglycerides; 11103-57-4/Vitamin A; 127-47-9/retinol acetate; 7235-40-7/beta Carotene |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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