Protection of vitamin A status in Chinese children by a dietary intervention with vegetables

A study of seasonal fluctuation of serum vitamin A concentrations in children in northern China showed that the prevalence of low serum levels of vitamin A was due to seasonal changes in the intakes of carotenoids. To determine whether plant carotenoids could sustain or improve children's vitamin A status during the fall and winter seasons, we performed an intervention with vegetables starting in the fall in Shandong, China. At a kindergarten, the serum vitamin A concentration was less than 1.05 μmol/L in 39% of the children. For five days per week for 10 weeks, 22 children were each provided with approximately 238 g/day of green and yellow vegetables and 34 g/day of light-coloured vegetables. Nineteen children maintained their customary dietary intake in the fall season, which included 56 g/day of green and yellow vegetables and 224 g/day of light-coloured vegetables. Vitamins A-d₈ and A-d₄ were given before and after the interventions, respectively, and their enrichments in the circulation were determined by gas chromatography/mass spectrometry to investigate vitamin A body stores. The serum concentration of β-carotene improved in the group fed mainly green and yellow vegetables but decreased in the group fed mainly light-coloured vegetables. The serum concentration of retinol was sustained in the group fed mainly green and yellow vegetables but decreased in the group fed mainly light-coloured vegetables (p < .01). The isotope dilution tests confirmed that total body stores of vitamin A were sustained in the group fed mainly green and yellow vegetables but decreased by 27 μmol (7,700 μg), on average, per child in the group fed mainly light-coloured vegetables (p<.06). Dietary green and yellow vegetables can provide adequate vitamin A nutrition to kindergarten children and protect them from becoming vitamin A deficient during seasons when the provitamin A food source is limited.