近年来的研究结果表明,轻度维生素A缺乏(夜盲和/或毕脱氏斑)与儿童肠道、呼吸道等感染性疾病的发病率和死亡率明显相关。已知维生素A与维持正常视觉有密切关系,并对上皮细胞的正常分化和生长起重要作用,许多研究也证实维生素A对维持机体正常免疫功能是必需的,它的缺乏不仅影响体液、细胞免疫和其它免疫功能,也与抗感染、抗肿瘤免疫密切相关。儿童维生素A缺乏是目前大多数发展中国家普遍存在的营养问题,它对这些国家和地区儿童身体和生长发育所带来的不良后果,已受到人们的日益关注。世界卫生组织(WHO)正在进行一顶为期十年 In recent years, the results show that mild vitamin A deficiency (night blindness and / or Bild’s spot) and intestinal infectious diseases such as children, respiratory morbidity and mortality were significantly correlated. It is known that vitamin A is closely related to the maintenance of normal vision and plays an important role in the normal differentiation and growth of epithelial cells. Many studies also confirm that vitamin A is necessary for maintaining the normal immune function of the body, and its deficiency not only affects humoral and cellular immunity And other immune functions, but also with anti-infection, anti-tumor immunity are closely related. The lack of vitamin A in children is a common nutritional problem in most developing countries. Its adverse consequences on the physical and growth of children in these countries and regions have drawn increasing attention. The World Health Organization (WHO) is undergoing a ten-year period