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.

[Effect of vitamin A supplements on iron metabolic homeostasis for preschoolers].

OBJECTIVE: To explore the effect of vitamin A (VA) combined iron supplements on iron metabolic homeostasis for preschoolers. METHODS: About 445 preschoolers with aged 3-6 years old from eight kindergartens in Pixian county, Chengdu were recruited into this trial from March to September, 2011. All subjects met the inclusion criteria were randomly divided into four groups using random number table: sole VA supplementation group (VA group, a single oral dose of VA at about 200 000 units), sole iron supplementation group (FE group, daily oral supplementation with the element iron 1-2 mg·kg(-1)·d(-1) for five days a week, lasting for 6 months), the combined supplementation of VA and iron group (VF group) and control group (CO group, no VA and iron supplementation). The concentration of serum VA, serum ferritin (SF), serum transferring receptor (sTfR), C-reactive protein (CRP) and hemoglobin (Hb) were measured from 3 ml vein blood. The sTfR-SF index (TFR-F index) and total body iron content (TBIC) before and after intervention were calculated. The differences of these indexes between groups before and after intervention were analyzed. RESULTS: The level of sTfR before intervention in VA group ((1.78 ± 0.17) mg/L) was significantly higher than that of after intervention ((1.18 ± 0.11)mg/L) (t = 28.88, P < 0.01). The levels of TFR-F index and TBIC in FE and VF groups before intervention ( (1.59 ± 0.37), (1.63 ± 0.40) and (9.04 ± 2.71), (9.26 ± 2.33) mg/kg, respectively) were all lower than those of after intervention (TFR-F index:(1.84 ± 0.51), (1.87 ± 0.45) and TBIC:(12.42 ± 3.49), (13.01 ± 2.98)mg/kg) (t values were 3.93, 3.78, 7.57 and 9.41, respectively, all P values were <0.01). The incidence of iron deficiency in VA, FE, and VF groups before intervention were 26% (25/95), 31% (30/98) and 31% (28/90) and were 41% (39/95), 10% (10/98) and 18% (16/90) for after intervention, respectively. The difference of this index in VA, FE and VF groups were significant (χ(2) values were 4.59, 12.50 and 4.31, respectively, all the P values were <0.05). CONCLUSION: Combined VA and iron was as effective as VA alone or iron alone in decreasing the iron deficiency, the impact of VA intervention on iron metabolic homeostasis was mainly manifested in iron usage and mobilization, but showed no effect on total body iron content.

Effect of simultaneous supplementation of vitamin A and iron on diarrheal and respiratory tract infection in preschool children in Chengdu City, China.

OBJECTIVE: The goal of this study was to investigate whether vitamin A combined with iron supplementation for preschool children resulted in improved changes in children's infectious morbidity. METHOD: In this randomized placebo-controlled and blinded field intervention trial, totally 445 preschoolers, ages 3 to 6 y old, were randomly selected. All children were randomly divided into four groups: vitamin A supplement-only group (group I), iron supplement-only group (group II), vitamin A and iron supplement group (group III), and no vitamin A and ferrous sulfate as placebo-control (group IV) for 6 mo. The morbidity of diarrhea and respiratory infections, were collected during supplementation. RESULTS: There was evidence of the lowest incidence rate of respiratory-related illnesses and fewest symptoms of runny nose, cough, and fever for children in group III compared with children in groups I, II and IV (P < 0.05). Moreover, despite the undistinguished incidence rate of vomiting, nausea, and stomach pain, the rate of diarrhea-related illness was significantly lower for children in group III than for those in the other three groups. CONCLUSION: The beneficial affects on infectious morbidity over 6 mo, highlight the potential of vitamin A plus an iron supplement for preschool-aged children.