MILD-TO-MODERATE ZINC-DEFICIENCY IN SHORT CHILDREN - EFFECT OF ZINC SUPPLEMENTATION ON LINEAR GROWTH VELOCITY

Twenty-one prepubertal, short Japanese children (11 boys) without endo crine abnormalities were identified as having mild-to-moderate zinc de ficiency by zinc kinetics studies (zinc body clearance greater-than-or -equal-to 20 ml/kg per hour). Only one child had a serum zinc level <6 5 mug/dl (cutoff level). A total of 10 children (5 boys) received 5 mg /kg per day of zinc sulfate for 6 months; 11 untreated children (6 boy s) served as control subjects. During treatment, calorie intake (p <0. 01), growth velocity (p <0.01), serum zinc, calcium, and phosphorus co ncentrations, alkaline phosphatase activity (p <0.001), percentage of tubular reabsorption of phosphorus (p <0.05), ratio of maximal tubular reabsorption rate for phosphorus to the glomerular filtration rate (p <0.05), serum osteocalcin level (p <0.01), and plasma insulin-like gr owth factor 1 (p <0.05) were significantly increased, but urinary excr etion of growth hormone was unchanged in the zinc-supplemented group. All these values were unchanged in the untreated children. We conclude that zinc supplementation is effective for inducing growth in short c hildren with zinc deficiency, and that body zinc clearance tests facil itate detection of marginal zinc deficiency.