The effect of vitamin A fortification of sugar on iron metabolism in preschool children in Guatemala.

The effect of improvement in vitamin A nutriture on biochemical indicators of iron nutrition during national vitamin A fortification of sugar was investigated longitudinally. Four "paired-comparison-subgroups" of preschoolers were studied before fortification (survey I) and, respectively, at 6 months (survey I versus II), at 1 yr (survey I versus III), at 1 1/2 yr (survey I versus IV), and at 2 yr (survey I versus V) after fortification began. Comparing I versus II gave a positive correlation (p less than 0.001) between changes in serum retinol or retinol-binding protein and changes in iron, total iron binding capacity, and percentage transferrin saturation. In contrast, changes in serum ferritin correlated negatively (p less than 0.05). Comparing V with I, retinol, retinol-binding protein, iron, and percentage transferritin saturation increased, but ferritin also increased (p less than 0.05). Consequently, the distribution of serum iron and ferritin values of the children improved (p less than 0.05). Because dietary iron did not change through the study period, the results suggest that vitamin A fortification had a favorable effect on iron metabolism and nutritional status.