Udomkesmalee E, Dhanamitta S, Sirisinha S, Charoenkiatkul S, Tuntipopipat S, Banjong O, Rojroongwasinkul N, Kramer T R, Smith J C
Institute of Nutrition, Mahidol University at Salaya, Nakorn Pathom, Thailand.
Am J Clin Nutr. 1992 Jul;56(1):50-7. doi: 10.1093/ajcn/56.1.50.
Previous surveys suggested that young children in Northeast Thailand may benefit from vitamin A and/or zinc supplementation. One hundred thirty-three children aged 6-13 y with marginal plasma retinol (less than 1.05 mumol/L) and Zn (less than 12.2 mumol/L) concentrations participated in a double-blind study. They were randomly assigned and supplemented with either zinc (25 mg/d), vitamin A (1500 RE/d), zinc plus vitamin A, or placebo for 6 mo. Biochemical indices of vitamin A (plasma vitamin A, retinol-binding protein) and zinc status (plasma zinc, alkaline phosphatase) increased significantly. The children had adequate liver stores of vitamin A (relative dose response less than 20%). Zinc supplementation resulted in an improvement in vision restoration time (VRT) in dim light (dark adaptometry). Vitamin A and zinc synergistically normalized conjunctival epithelium as measured by conjunctival impression cytology (CIC). Both functional indices, VRT and CIC, showed significant correlations with plasma zinc and vitamin A, respectively. The data suggest that functional improvements in populations with suboptimal vitamin A and zinc nutriture can be accomplished by supplementation with less than two times the recommended dietary allowance of these nutrients.
以往的调查表明，泰国东北部的幼儿可能从维生素A和/或锌补充剂中获益。133名6至13岁的儿童参与了一项双盲研究，这些儿童的血浆视黄醇（低于1.05μmol/L）和锌（低于12.2μmol/L）浓度处于边缘水平。他们被随机分配，分别补充锌（25毫克/天）、维生素A（1500视黄醇当量/天）、锌加维生素A或安慰剂，为期6个月。维生素A（血浆维生素A、视黄醇结合蛋白）和锌状态（血浆锌、碱性磷酸酶）的生化指标显著提高。这些儿童肝脏中的维生素A储备充足（相对剂量反应低于20%）。补充锌使暗光下的视力恢复时间（VRT，暗适应测量法）得到改善。通过结膜印片细胞学检查（CIC）测量，维生素A和锌协同使结膜上皮恢复正常。两项功能指标，即VRT和CIC，分别与血浆锌和维生素A显示出显著相关性。数据表明，对于维生素A和锌营养状况欠佳的人群，补充低于这些营养素推荐膳食摄入量两倍的剂量即可实现功能改善。
