Author(s):
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Loo-Bouwman, C.A. Van;
Naber, T.H.
; Breemen, R.B. van; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.;
Russel, F.G.M.
; Schaafsma, G.; West, C.E.
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Subject:
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IGMD 2: Molecular gastro-enterology and hepatology NCMLS 5: Membrane transport and intracellular motility Synthetic Organic Chemistry |
Organization:
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Gastroenterology IMM - Institute for Molecules and Materials Pharmacology-Toxicology |
Journal title:
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British Journal of Nutrition
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Abstract:
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The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, cross-over intervention study. Each subject followed both diets for 2 weeks: a diet containing vegetables low in beta-carotene content with supplemental beta-carotene in salad dressing oil ('oil diet'; mean beta-carotene intake 3.1 mg/d) and a diet containing vegetables and fruits high in beta-carotene content ('mixed diet'; mean beta-carotene intake 7.6 mg/d). Daily each subject consumed a mean of 190 microg [13C10]beta-carotene and 195 microg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of beta-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum. Apparent absorption of beta-carotene was determined with oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]beta-carotene in oil of 3.6:1 (95 % CI 2.8, 4.6) regardless of dietary matrices differences. The apparent absorption of (labelled and dietary) beta-carotene from the 'oil diet' (30 %) was 1.9-fold higher than from the 'mixed diet' (16 %). This extrinsic labelling technique can measure precisely the vitamin A equivalency of beta-carotene in oil capsules, but it does not represent the effect of different dietary matrices.
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