Serum carotenoid concentrations and their reproducibility in children in Belize

Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood sample 2 wk after the first collection from a subset of children (n = 23) who consumed their habitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26% and 24% of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoxanthin, constituted 51% of median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentration indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrations determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-carotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggests both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or = 2 wk without significant bias.