IMPACT OF HARD WATER CONSUMPTION AND ZINC SUPPLEMENTATION ON THE ZINC STATUS OF A GROUP OF PRESCHOOLERS IN NORTHWEST INDIANA
Abstract
Zinc is critical to normal growth in children. In this country mild levels of zinc undernutrition have been observed in healthy preschoolers from widely varying socioeconomic levels. However the implications of these observations for clinical practice and for dietary adjustment or zinc supplementation are unclear since few studies have related dietary zinc levels as well as zinc complexing factors to growth and other measures of zinc status. Poor zinc status in children has been associated with depressed growth, reduced taste acuity and lowered concentrations of zinc in hair. In this study these parameters were used as measures of zinc status of 3- to 6-year-old males and females before and after zinc supplementation. Children were fed cereal supplemented with 3.75 mg zinc/ounce or a non-zinc-supplemented cereal over a period of 3 months. Total zinc intake was evaluated at the beginning and end of the study period by use of 3-day diet records. Levels of phytate and calcium, two dietary components known to interfere with absorption of zinc, were also assessed. Estimates of calcium intake included amounts of calcium in water used in food preparation and beverages. Children who consumed water from supplies considered very hard (CaCO3 above 200 ppm) were significantly lower in height-for-age centiles than children who consumed softer drinking water. However, total calcium intake did not differ significantly between the two groups. Mean dietary zinc of the preschoolers before zinc supplementation was 7.02 $\pm$ 0.5 mg/day. After zinc-supplemented cereal was fed for 3 months mean zinc intake of this group of preschoolers was 9.05 $\pm$ 0.4 mg/day whereas the non-zinc-supplemented group showed no change in zinc intake. Concomitant with zinc supplementation dietary phytate:zinc and calcium:zinc ratios decreased significantly, suggesting less potential for zinc complexing during absorption. Taste acuity improved and concentrations of zinc in hair increased with zinc supplementation. In males the increase in height over the 3-month study period was significantly correlated with dietary zinc. The greatest response was observed among those males who initially showed multiple markers of poor zinc status. Hence the results of this study indicated that zinc-supplemented cereals helped improve the zinc status of preschoolers who showed some signs of zinc inadequacy.
Degree
Ph.D.
Subject Area
Nutrition
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