1 Concentrations of carotenoids and tocopherols in 2 breast milk from urban Chinese mothers and their 3 associations with maternal characteristics : a 4 cross - sectional study 5

This study aims to quantify carotenoids and tocopherols in human milk from healthy 19 Chinese women, and to explore their associations with region, lactation stage, and maternal 20 socio-economic and obstetric factors. Human milk was obtained from 509 healthy mothers and the 21 compounds of carotenoids and tocopherols were analyzed by high-performance liquid 22 chromatography after mild saponification and solvent extraction. Socio-economic and obstetric 23 characteristics of the mothers and their dietary intakes through a single 24-hour dietary recall were 24 evaluated. The median content of each component [μg/100mL, median (interquartile range)] in 25 colostrum and mature milk was, respectively, β-carotene 8.0 (4.7-15.2) and 1.8 (1.4-2.7), 26 β-cryptoxanthin 6.2 (2.4-12.9) and 1.8 (1.1-3.4), lutein 5.7 (2.9-10.2) and 3.4 (1.5-6.0), lycopene 6.3 27 (4.0-9.9) and 1.4 (1.1-2.0), zeaxanthin 1.0 (0.6-1.5) and 1.0 (0.6-1.4), α-tocopherol 645 (388-1176) and 28 211 (131-321), γ-tocopherol 68 (48-121) and 77 (45-120). The levels of all those vitamins presented 29 regional differences, and decreased as lactation stage increased except for zeaxanthin and 30 γ-tocopherol. Associations of carotenoid contents with maternal education, delivery mode, and 31 present body mass index were found in multivariate analyses. These results suggest that some 32 region, lactation stage, obstetric and socio-economic factors are associated with human milk 33 concentrations of carotenoids and tocopherols in healthy Chinese mothers. 34