Children with Sub-Clinical Vitamin-A Deficiency are at Risk for Significant Nutritional Iron and Zinc Deficiencies

Nutrient interaction and vitamin A deficiency were studied using several biochemical markers of nutritional deficiency in 100 socio-economically deprived children living in the slums of Mumbai, India. The purpose of the study was to examine whether children with sub-clinical vitamin A deficiency are at risk for nutritional iron and zinc deficiencies. Children were originally identified to suffer from sub-clinical vitamin A deficiency as manifested by the presence of abnormal conjunctival impression cytology for early epithelial changes with/without associated (1) night blindness (XN), (2) conjunctival xerosis (XIA) or (3) bitot's spots (XIB). Twenty five per cent of these children had adequate serum vitamin A levels (>0.698μmol/L) thereby suggesting that vitamin A levels were insensitive for determining likelihood of clinical disease. In contrast Retinol Binding Protein (RBP) measurements more accurately profiled the clinical disease status. All children with sub-clinical vitamin A deficiency had significantly lower RBP values compared to control children. In addition, these children had significant iron-deficiency anemia (hemoglobin 99.5 g/dL) and low serum iron along with low serum zinc compared to control children. These results suggest that malnourished children with sub-clinical evidence of vitamin A deficiency, despite normal vitamin A levels were at risk of inadequate iron and zinc nutriture. Children with sub-clinical vitamin A deficiency should receive vitamin A therapy that includes iron and zinc supplementation. Furthermore, this points to a significant under-reported health problem that impacts intellectual development of many of the world's children.