Bioefficacy of beta-carotene dissolved in oil studied in children in Indonesia

Background: More information on the bioefficacy of carotenoids in foods ing ested by humans is needed. Objective: We aimed to measure the time required for isotopic enrichment of beta -carotene and retinol in serum to reach a plateau, the extent of conv ersion of beta -carotene dissolved in oil with use of beta -carotene and re tinol specifically labeled with 10 C-13 atoms, and the intraindividual vari ation in response. Design: Indonesian children aged 8-11 y (n = 35) consumed 2 capsules/d, 7 d /wk, for less than or equal to 10 wk. Each capsule contained 80 mug [12,13, 14,15,20,12',13',14',15',20'-C-13(10)]beta -carotene and 80 mug [8,9,10,11, 12,13,14,15,19,20-C-13(10)]retinyl palmitate. Three blood samples were draw n per child over a period of less than or equal to 10 wk, HPLC coupled with atrnosphrric pressure chemical ionization liquid chromatography-mass spect rometry was used to measure the isotopic enrichment in serum of retinol wit h [C-13,]retinol and [C-13(10)]retinol and of beta -carotene with [C-13(10) ]beta -carotene. The beta -carotene in the capsules used had a cis-trans ra tio of 3:1, Results: Plateau isotopic enrichment was reached by day 21. The amount or p -carotene in oil required to form 1 mug retinol was 2.4 mug (95% CI: 2.1, 2 .7). The amount of all-trans-beta -carotene required to form 1 mug retinol may be lower. Conclusions: The efficiency of conversion of this beta -carotene in oil was 27% better than that estimated previously (1.0 mug retinol from 3.3 mug be ta -carotene with an unknown cis-trans ratio). The method described can be extended to measure the bioefficacy of carotenoids in foods with high preci sion, requiring fewer subjects than other methods.