ABSTRACT
BACKGROUND: Deficiencies of vitamin A and its precursors, the carotenoids are common problems in developing countries. Plasma levels of these components are used as biomarkers of their availability. The study was conducted to evaluate whether blood plasma obtained from capillaries can be compared with plasma obtained from venous blood with regard to its levels of retinol, carotenoids and alpha-tocopherol and secondly to apply this technique to evaluate the levels of these components in children in a region with possible deficiencies. METHODS: The survey was conducted in a region of Laos in 81 children (age 35 to 59 months). Dietary intake was assessed by a questionnaire. Retinol, carotenoids and alpha-tocopherol were determined by HPLC. Blood plasma was obtained either from capillary blood collected into microcapillaries and for reasons of methodological comparison in 14 adults from venous blood. RESULTS: The comparison between capillary and venous blood revealed that all components except zeaxanthin were 9-23 % higher in plasma obtained from capillary blood. Results in Laotian children showed that all investigated components except retinol were significantly lower (P < 0.01) compared to European children of slightly older age. Contrary to children in Europe, most components were significantly lower in boys compared to girls. In children from Laos, lutein was the dominant carotenoid, while in children in Europe, beta-carotene was dominant. Within the Laotian children only a few differences were observed between stunted and non-stunted children and between children from lowland areas and high land areas. CONCLUSIONS: Results show that in consideration of slightly lower levels than in venous blood, capillary blood can be used to evaluate retinol, carotenoids and alpha-tocopherol as biomarkers of intake or status and to evaluate the possible effect of diet on absolute and relative carotenoid composition in children from Europe and Laos. Observed sex related differences might not be related to diet and would need further investigation.
