Vitamin A equivalency and apparent absorption of beta-carotene in ileostomy subjects using a dual-isotope dilution technique.
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.
Department of Gastroenterology and Hepatology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. Carolien.VanLooBouwman@hotmail.com
Carolien A
CA
Van Loo-Bouwman
Ton H J
TH
Naber
Richard B
RB
van Breemen
Dongwei
D
Zhu
Heleen
H
Dicke
Els
E
Siebelink
Paul J M
PJ
Hulshof
Frans G M
FG
Russel
Gertjan
G
Schaafsma
Clive E
CE
West
D000328:Adult; D002214:Capsules; D018592:Cross-Over Studies; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage*; D004224:Diterpenes; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D007081:Ileostomy; D007201:Indicator Dilution Techniques; D007408:Intestinal Absorption; D007554:Isotopes; D008297:Male; D008875:Middle Aged; D000084562:Retinyl Esters; D014801:Vitamin A / Q000031:analogs & derivatives / Q000032:analysis* / Q000097:blood; D019207:beta Carotene / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*
D002214:Capsules; D004041:Dietary Fats; D004224:Diterpenes; D007554:Isotopes; D000084562:Retinyl Esters; D019207:beta Carotene; D014801:Vitamin A; C014794:retinol palmitate