No enhancing effect of vitamin A administration on iron absorption or body total iron content in preschool children from Chengdu, China.

To explore the effect of vitamin A supplements on iron metabolic homeostasis for preschoolers. This was a randomized, placebo-controlled and blinded intervention trial with 3- to 6-y old preschoolers. A total of 445 subjects were randomly divided into four groups: a vitamin A supplementation group (group 1, a single oral dose of vitamin A as retinol 200,000 IU), an iron supplement group (group 2, daily oral supplement with the elemental iron 1-2 mg/kg/d for 5 d a week, lasting for 6 mo) a combined vitamin A and iron (group 3) and administration of no vitamin A or iron as a placebo-control (group 4). A total of 387 (95, 98, 90 and 104 from groups 1, 2, 3 and 4) children completed the intervention. After intervention, serum retinol levels of children in group 1 and group 3 was markedly higher than those of children in groups 2 and 4 (p<0.05). The serum ferritin level of children in group 1 significantly decreased after intervention (p<0.05), but increased in group 2 (p<0.05). The sTfR-SF index (TFR-F) and total body iron content (BTIC) showed the same change after intervention. In group 2 and group 3, the levels of TRF-F index and BTIC had statistically increased to the same degree after intervention (p<0.05). The impact of vitamin A intervention on iron metabolic homeostasis was mainly manifested in storage and mobilization; there was no direct effect on total body iron content or iron absorption in the intestine.