Effects of vitamin A, vitamin A plus iron and multiple micronutrient-fortified seasoning powder on preschool children in a suburb of Chongqing, China.

Preschool children in developing countries are likely to have multiple, concurrent micronutrient deficiencies. This study was designed to evaluate the effectiveness of different combinations of nutritional fortified diet to improve the blood levels of iron, vitamin A and other essential micronutrients in the preschool population of Banan District of Chongqing, China. From December 2005 to June 2006, a total of 226 2-6 y old preschool children were recruited from three nurseries in the area, and they were randomly assigned to three different fortified diet groups for 6 mo. Group I was fortified with vitamin A; groups II and III were fortified with vitamin A plus iron and vitamin A plus iron, thiamine, riboflavin, folic acid, niacinamide, zinc and calcium, respectively. Subjects' weight and height were measured for assessing the children's growth and development. Blood samples were taken at the beginning and the end of the 6-mo study period for measuring serum levels of micronutrients. Group III with the multiple micronutrient fortified diet was the most effective to improve the serum level of retinol from [media (P25, P75): 1.06 (0.89, 1.32)] micromol/L to 1.29 (1.04, 1.39) micromol/L (p<0.05) and retinol binding protein from 17.0 (12.6, 25.6) mg/L to 31.6 (24.4, 44.0) mg/L (p<0.05) and to mobilize the stored iron in the liver (p<0.05). In addition, the three groups' hemoglobin levels were elevated from 117.0 (109.0, 124.1) g/L, 114.0 (109.2, 119.7) g/L and 115.0 (109.5, 122.7) g/L to 125.7 (119.2, 133.1) g/L, 126.5 (122.2, 135.9) g/L and 125.1 (119.8, 131.6) g/L over the 6 mo of intervention period, but there were no difference among the three groups (p>0.05). Nevertheless, unexpected results were obtained when comparing the effects on growth status among the different supplement groups. Our study has demonstrated that a multiple micronutrient fortified diet for 6 mo is more effective to improve the levels of hemoglobin, serum retinol, and RBP as well as to facilitate the mobilization of iron storage in preschool children.