Vitamin A and iron supplementation of Indonesian pregnant women benefits vitamin A status of their infants.

Many Indonesian infants have an inadequate nutritional status, which may be due in part to inadequate maternal nutrition during pregnancy. This study was designed to investigate whether infant nutritional status could be improved by maternal vitamin A and Fe supplementation during gestation. Mothers of these infants from five villages had been randomly assigned on an individual basis, supervised and double-blind, to receive supplementation once weekly from approximately 18 weeks of pregnancy until delivery. Supplementation comprised 120 mg Fe and 500 microg folic acid with or without 4800 retinol equivalent vitamin A. Mothers of infants from four other villages who participated in the national Fe and folic acid supplementation programme were also recruited; intake of tablets was not supervised. Anthropometric and biochemical parameters of infants and their mothers were assessed approximately 4 months after delivery. Infants of mothers supplemented with vitamin A plus Fe had higher serum retinol concentrations than infants of mothers supplemented with Fe alone. However, the proportion of infants with serum retinol concentrations <0.70 micromol/l was >70 % in all groups. Maternal and infant serum retinol concentrations were correlated. Fe status, weight and length of infants were similar in all groups. Fe status of girls was better than that of boys, but boys were heavier and longer. We conclude that supplementation with vitamin A in conjunction with Fe supplementation of women during pregnancy benefits vitamin A status of their infants. However, considering the large proportion of infants with marginal serum retinol concentrations, it may still be necessary to increase their vitamin A intake.     

Vitamin A and iron status are improved by vitamin A and iron supplementation in pregnant Indonesian women

In Indonesia, deficiencies of vitamin A and iron are of public health concern during pregnancy. We sought to determine the effects of vitamin A and iron supplementation on the vitamin A and iron status of pregnant Indonesian women. The women (n = 27) were randomly assigned to four groups. The modified relative dose response (MRDR) test for vitamin A status and hemoglobin, hematocrit and ferritin values were determined at baseline. Thereafter, daily supplements were administered: placebo [Pl] (n = 7), 8.4 micromol vitamin A [A] (n = 7), 1.07 mmol iron [Fe] (n = 5), and 8.4 micromol vitamin A plus 1.07 mmol iron [A + Fe] (n = 8). Post-treatment tests were performed after 8 wk. The MRDR value was reduced, i.e., vitamin A status improved, more markedly by the combination of vitamin A and iron than by either nutrient alone (P = 0.034). The decrease in the MRDR relative to baseline was significant in the A + Fe group (P = 0.008). Iron status was also significantly improved in these women (P < 0.05) with both iron and vitamin A supplementation. The mechanism of the enhancing effect of iron on the vitamin A-induced reduction in the MRDR is not known.     

Weekly vitamin A and iron supplementation during pregnancy increases vitamin A concentration of breast milk but not iron status in Indonesian lactating women

Studies on the effect of vitamin A and iron supplementation during pregnancy on maternal iron and vitamin A status postpartum are scarce. We investigated whether retinol and iron variables in breast milk and in serum postpartum were enhanced more with weekly vitamin A and iron supplementation during pregnancy than with weekly iron supplementation. During pregnancy, subjects were randomly allocated to two groups and received either (n = 88) a weekly supplement of iron (120 mg Fe as FeSO(4)) and folic acid (500 microg) or (n = 82) the same amount of iron and folic acid plus vitamin A [4800 retinol equivalents (RE)]. Transitional milk (4-7 d postpartum) had higher (P < 0.001) concentrations of retinol and iron than mature milk (3 mo postpartum). Compared with the weekly iron group, the weekly vitamin A and iron group had a greater (P < 0.05) concentration of retinol in transitional milk (as micromol/L) and in mature milk (as micromol/g fat). Although serum retinol concentrations approximately 4 mo postpartum did not differ significantly, the weekly vitamin A and iron group had significantly fewer (P < 0.01) subjects with serum retinol concentrations < or = 0.70 micromol/L than the weekly iron group. Iron status and concentrations of iron in transitional and mature milk did not differ between groups. We have shown that weekly vitamin A and iron supplementation during pregnancy enhanced concentrations of retinol in breast milk although not in serum by approximately 4 mo postpartum. However, no positive effects were observed on iron status and iron concentration in breast milk.     

A community-based randomized controlled trial of iron and zinc supplementation in Indonesian infants: interactions between iron and zinc

BACKGROUND: Combined supplementation with iron and zinc during infancy may be effective in preventing deficiencies of these micronutrients, but knowledge of their potential interactions when given together is insufficient. OBJECTIVE: The goal was to compare the effect in infants of combined supplementation with iron and zinc and of supplementation with single micronutrients on iron and zinc status. DESIGN: Indonesian infants (n = 680) were randomly assigned to daily supplementation with 10 mg Fe (Fe group), 10 mg Zn (Zn group), 10 mg Fe + 10 mg Zn (Fe+Zn group), or placebo from 6 to 12 mo of age. Venous blood samples were collected at the start and end of the study. Five hundred forty-nine infants completed the supplementation and had both baseline and follow-up blood samples available for analysis. RESULTS: Baseline prevalences of anemia, iron deficiency anemia (anemia and low serum ferritin), and low serum zinc (< 10.7 micromol/L) were 41%, 8%, and 78%, respectively. After supplementation, the Fe group had higher hemoglobin (119.4 compared with 115.3 g/L; P < 0.05) and serum ferritin (46.5 compared with 32.3 microg/L; P < 0.05) values than did the Fe+Zn group, indicating an effect of zinc on iron absorption. The Zn group had higher serum zinc (11.58 compared with 9.06 micromol/L; P < 0.05) than did the placebo group. There was a dose effect on serum ferritin in the Fe and Fe+Zn groups, but at different levels. There was a significant dose effect on serum zinc in the Zn group, whereas no dose effect was found in the Fe+Zn group beyond 7 mg Zn/d. CONCLUSION: Supplementation with iron and zinc was less efficacious than were single supplements in improving iron and zinc status, with evidence of an interaction between iron and zinc when the combined supplement was given.     

Effects of iron and zinc supplementation in Indonesian infants on micronutrient status and growth.

In this study the effects of supplementation of iron and zinc, alone or combined, on iron status, zinc status and growth in Indonesian infants is investigated. Micronutrient deficiencies are prevalent in infants in developing countries, and deficiencies often coexist; thus, combined supplementation is an attractive strategy. However, little is known about interactions between micronutrients. In a randomized, double-blind, placebo-controlled supplementation trial, 478 infants, 4 mo of age, were supplemented for 6 mo with iron (10 mg/d), zinc (10 mg/d), iron + zinc (10 mg of each/d) or placebo. Anthropometry was assessed monthly, and micronutrient status was assessed at the end of supplementation. Supplementation significantly reduced the prevalence of anemia, iron deficiency anemia and zinc deficiency. Iron supplementation did not negatively affect plasma zinc concentrations, and zinc supplementation did not increase the prevalence of anemia or iron deficiency anemia. However, iron supplementation combined with zinc was less effective than iron supplementation alone in reducing the prevalence of anemia (20% vs. 38% reduction) and in increasing hemoglobin and plasma ferritin concentrations. There were no differences among the groups in growth. The growth of all groups was insufficient to maintain the same Z-scores for height for age and weight for height. There is a high prevalence of deficiencies of iron and zinc in these infants, which can be overcome safely and effectively by supplementation of iron and zinc combined. However, overcoming these deficiencies is not sufficient to improve growth performance in these infants.     

A community-based randomized controlled trial of iron and zinc supplementation in Indonesian infants: effects on growth and development

BACKGROUND: Deficiencies of iron and zinc are associated with delayed development, growth faltering, and increased infectious-disease morbidity during infancy and childhood. Combined iron and zinc supplementation may therefore be a logical preventive strategy. OBJECTIVE: The objective of the study was to compare the effects of combined iron and zinc supplementation in infancy with the effects of iron and zinc as single micronutrients on growth, psychomotor development, and incidence of infectious disease. DESIGN: Indonesian infants (n = 680) were randomly assigned to daily supplementation with 10 mg Fe (Fe group), 10 mg Zn (Zn group), 10 mg Fe and 10 mg Zn (Fe+Zn group), or placebo from 6 to 12 mo of age. Anthropometric indexes, developmental indexes (Bayley Scales of Infant Development; BSID), and morbidity were recorded. RESULTS: At 12 mo, two-factor analysis of variance showed a significant interaction between iron and zinc for weight-for-age z score, knee-heel length, and BSID psychomotor development. Weight-for-age z score was higher in the Zn group than in the placebo and Fe+Zn groups, knee-heel length was higher in the Zn and Fe groups than in the placebo group, and the BSID psychomotor development index was higher in the Fe group than in the placebo group. No significant effect on morbidity was found. CONCLUSIONS: Single supplementation with zinc significantly improved growth, and single supplementation with iron significantly improved growth and psychomotor development, but combined supplementation with iron and zinc had no significant effect on growth or development. Combined, simultaneous supplementation with iron and zinc to infants cannot be routinely recommended at the iron-to-zinc ratio used in this study.     

Mental and psychomotor development in Indonesian infants of mothers supplemented with vitamin A in addition to iron during pregnancy

Maternal nutrition is important for fetal development, but its impact on the functional outcome of infants is still unclear. The present study investigated the effects of vitamin A and Fe supplementation during gestation on infant mental and psychomotor development. Mothers of infants from five villages in Indonesia were randomly assigned to supervised, double-blind supplementation once per week from approximately 18 weeks of pregnancy until delivery. Supplementation comprised 120 mg Fe+500 microg folic acid with (n 94) or without (n 94) 4800 microg retinol in the form of retinyl acetate. Mothers of infants who participated in the national Fe+folic acid supplementation programme, but whose intake of supplements was not supervised, were recruited from four other villages (n 88). The mental and psychomotor development of infants was assessed, either at 6 or 12 months of age, using the Bayley Scales of Infant Development (BSID). We found no impact of vitamin A supplementation on mental or psychomotor development of infants. In addition, infants whose mothers had received weekly Fe supplementation had similar mental and psychomotor indices as those whose mothers had participated in the governmental Fe supplementation programme. The study population was moderately Fe and vitamin A deficient. The size of the treatment groups was large enough to detect a mean difference of 10 points on the BSID, which is less than 1 sd (15 points) of the average performance of an infant on the BSID. In conclusion, the present study did not find an impact of weekly supplementation of 4800 RE vitamin A in addition to Fe during gestation on functional development of Indonesian infants. However, smaller improvements in development may be seen if studied in a larger and/or more deficient population.     

Weekly supplementation with iron and vitamin A during pregnancy increases hemoglobin concentration but decreases serum ferritin concentration in Indonesian pregnant women

We investigated whether weekly iron supplementation was as effective as the national daily iron supplementation program in Indonesia in improving iron status at near term in pregnancy. In addition, we examined whether weekly vitamin A and iron supplementation was more efficacious than weekly supplementation with iron alone. One group of pregnant women (n = 122)was supplemented weekly with iron (120 mg Fe as FeSO4) and folic acid (500 microg); another group (n = 121) received the same amount of iron and folic acid plus vitamin A [4800 retinol equivalents (RE)]. A third ("daily") group (n = 123), participating in the national iron plus folic acid supplementation program, was also recruited. Data on subjects with complete biochemical data are reported (n = 190). At near term, hemoglobin concentrations increased, whereas serum ferritin concentrations decreased significantly in the weekly vitamin A and iron group, suggesting that vitamin A improved utilization of iron for hematopoiesis. Iron status in the weekly iron group was not different from that of the "daily" group. However, iron status decreased with daily supplementation if <50 iron tablets were ingested. Serum transferrin receptor concentrations increased in all groups (P < 0.01). Serum retinol concentrations were maintained in the weekly vitamin A and iron group, but decreased in the other two groups (P < 0.01). Thus, delivery of iron supplements on a weekly basis can be as effective as ona daily basis if compliance can be ensured. Addition of vitamin A to the supplement improved hemoglobin concentration.     

Zinc supplementation and plasma concentration of vitamin A in preterm infants

To assess the effect of zinc supplementation on plasma retinol levels, 24 preterm infants were randomly assigned to receive 400 micrograms.kg-1.d-1 of intravenous Zn or no Zn supplementation. Intakes of protein, energy, and vitamin A were similar for both groups as were day 0 plasma concentrations of retinol, retinol-binding protein (RBP), and Zn. Zn concentrations were not significantly different between groups at any time during the 3-wk study; however, retinol values in wk 1 increased more in the supplemented group (delta = 10.0 vs 0.9 micrograms/dL, or 0.35 vs 0.031 mumol/L; p less than 0.005). RBP appeared to increase more in the supplemented group but did not reach statistical significance. We hypothesize that the increase in plasma retinol levels noted in the preterm infants receiving Zn supplementation may be mediated by an increased production of RBP in the liver that in turn enhances the hepatic release of retinol.     

Effect of vitamin A supplementation on measles vaccination in nine-month-old infants

Objective: Childhood immunization programs have been suggested as an infrastructure to deliver vitamin A supplements to children in developing countries. The effects of giving vitamin A, a potent immune enhancer, with measles immunization to nine-month-old infants is unknown.Methods: A randomized, double-masked, placebo-controlled clinical trial of vitamin A, 100 000 IU at the time of standard titer Schwarz measles immunization was conducted with nine-month-old infants in Bogor District, West Java, Indonesia. Antibody titers to measles were measured at baseline and one and six months following immunization.Results: 394 infants received measles immunization, and 37 infants (9.4%) had baseline antibody titers > 1:120, which is consistent with previous natural measles infection. Of the remaining infants, 98.8% seroconverted to measles, and 99.3% had titers consistent with protection against measles six months postimmunization. Seroconversion rates were similar in vitamin A and placebo treatment groups.Conclusion: High dose vitamin A supplementation can be given without reducing seroconversion to standard titer Schwarz measles immunization in nine-month-old infants.     

Reduced production of immunoregulatory cytokines in vitamin A- and zinc-deficient Indonesian infants

OBJECTIVE: To determine effects of vitamin A, zinc and iron deficiency in Indonesian infants on the ability to produce immunoregulatory cytokines. DESIGN, SETTING AND SUBJECTS: Immunological assessment was done in 59 infants participating in a cross-sectional nutritional survey in rural West Java, Indonesia. Production of T-helper cell type-1 (Th1, cell-mediated) cytokines interferon-gamma (IFN-gamma), interleukin-12 (IL-12), interleukin-18 (IL-18) and T-helper cell type-2 (Th2, humoral) cytokine interleukin-6 (IL-6) were measured after stimulation with lipopolysaccharide and phytohemagglutinin in an ex vivo whole blood culture system. Circulating neopterin concentrations were determined as an indicator of in vivo macrophage activity. RESULTS: Of the infants, 48% were vitamin A deficient, 44% were anemic (with 17% having iron deficiency anemia), and 17% were zinc deficient. Vitamin-A deficient infants had significantly reduced ex vivo production of IFN-gamma, but also significantly higher circulating neopterin concentrations. Production of IFN-gamma and IL-12 were strongly correlated, IFN-gamma and IL-18 production were not. Zinc deficiency was accompanied by significantly reduced white blood cell counts and reduced ex vivo production of IL-6. Iron status was not related to cytokine production. CONCLUSIONS: This study shows that in vitamin A deficiency there is Th1 dominance in a steady state, combined however with impairment of the Th1 response after stimulation, whereas in zinc deficiency, there is a decreased Th2 response. Overall, vitamin A deficiency and zinc deficiency have marked albeit different effects on the immunocompetence of infants, affecting both cell-mediated and humoral components of the immune system.     

补充维生素A对健康成人铁营养状况的影响

目的观察健康成人补充维生素A(VA)后铁营养状况的变化。方法选择115名健康成人志愿者,按血清视黄醇浓度用区组设计方法将男女志愿者随机分入4组(男、女各半),在日常膳食的基础上,分别补充不同剂量的VA,干预剂量(以视黄醇计)分别为600μg/d(A组)、400μg/d(B组)、200μg/d(C组)和0μg/d(D组),干预期4个月。补充剂为微胶囊化的视黄酰乙酸酯,将5日剂量装入1粒胶囊,每5日口服1粒。胶囊外包装只标注剂量类型,现场实验人员和受试者均不知道每一种胶囊的补充类型。干预期内,受试者接受常规膳食,每月进行1次24h回顾性膳食调查。干预试验前后,采集空腹上臂静脉血,取血清测定血液血红蛋白(Hb)浓度,血清视黄醇、血清铁(SI)、铁蛋白(SF)和转铁蛋白受体(TfR)浓度。结果共有108名受试者完成干预试验,A、B、C和D组各为27、28、27和26名。干预期内,4组受试者膳食能量营养素、视黄醇当量(RE)和铁摄入量无显著性差异(P>0.05)。干预结束后,A组受试者血清视黄醇浓度从干预前的(1.63±0.55)μmol/L升高到了(1.93±0.52)μmol/L(P<0.05);B和C组血清视黄醇浓度分别平均升高了0.29μmol/L和0.14μmol/L(均为P<0.05);而对照组D组变化不显著(P>0.05)。干预试验前后各组Hb差异没有显著性(P>0.05);高剂量VA组受试者干预后SI浓度比干预前显著升高,而SF和TfR浓度则显著降低(均为P<0.05);中剂量组和低剂量组在干预前后SF和TfR未见显著性变化。结论铁营养状况正常的成人,在没有专门给予膳食铁干预的情况下,通过较大剂量VA补充干预,铁营养状况仍然得到进一步提高。     

Efficacy of iron supplementation with or without vitamin A for anemia control

This study aimed to evaluate the efficacy of weekly iron supplementation with or without vitamin A in the treatment of iron deficiency anemia, using an experimental, randomized, non-placebo-controlled design in 1999. 267 schoolchildren 6 to 14 years of age were randomized to two treatment groups: one group (144) received 200mg iron sulfate alone, with 40 mg of elemental iron, while the other (123) received the same iron supplementation dose plus 10,000 IU of vitamin A (both groups for 30 weeks). Final anemia prevalence was reduced from 48.4% to 17.7% (p < 0.001) in the group receiving iron supplementation alone and 58.1% to 14.3% (p < 0.001) in the group receiving iron plus vitamin A. There was no significant difference between the groups at the end of the study according to mean Hb (p = 0.355) and anemia (p = 0.479). There was a significant correction for iron deficiency anemia with weekly iron-alone supplementation, but with no additional advantage of vitamin A. New studies on the synergism between these two micronutrients are recommended.     

不同剂量维生素D补充在早产儿中的应用研究

目的 评估不同剂量维生素D补充对胎龄≤34周早产儿出院时维生素D水平的影响,为早产儿生后合理补充维生素D提供依据。方法 选择2019年1月—2020年6月在博罗县妇幼保健计划生育服务中心出生的胎龄≤34周早产儿67例,在完全肠内喂养后开始口服维生素D,并随机分为维生素D低剂量组(n=32)和高剂量组(n=35),比较两组患儿出院时25(OH)D水平、维生素D缺乏/不足的比例及相关不良反应发生率。结果 两组患儿出生时脐带血25(OH)D水平、维生素D缺乏/不足发生率比较,差异无统计学意义(P＞0.05);出院时高剂量组血清25(OH)D水平明显高于低剂量组、维生素D缺乏/不足发生率明显低于低剂量组(t=2.872、χ²=4.189,P＜0.05),但高剂量组出院时维生素D缺乏/不足发生率仍为28.6%。结论 对于胎龄≤34周的早产儿,给予补充维生素D 800 U/d可明显改善患儿出院时维生素D缺乏或不足的情况,但对于胎龄更小、出生体重更低的超低出生体重儿,可能需要更大剂量的维生素D补充。     

Does iron supplementation compromise zinc nutrition in healthy infants?

Iron supplements are commonly administered to infants in order to prevent iron deficiency. We wished to determine whether iron administration could compromise zinc nutrition as might be suspected from previous studies. Measures of iron nutrition, serum zinc, and serum copper were measured before and after randomization of 291 healthy 1-yr-old infants to a 3 mo course of placebo or iron treatment (30 mg iron as ferrous sulfate given before a meal). There was no significant difference in serum zinc or copper in the two groups before or after treatment; thus iron administration did not result in any evidence of zinc deficiency in a healthy, well-nourished group of T-yr-old infants.     

Vitamin E and vitamin C plasma levels in premature infants following supplementation of vitamin C

Our preliminary data suggest that supplementation of premature neonates with vitamin C is required to maintain adequate ascorbate plasma levels and may have a sparing effect on vitamin E metabolism. Further studies are required to validate our findings and evaluate the possible antioxidant advantage of ascorbic acid administration.     

Randomised double-blind trial of the effect of vitamin A supplementation of Indonesian pregnant women on morbidity and growth of their infants during the first year of life

OBJECTIVE: To investigate whether supplementation with vitamin A together with iron of Indonesian pregnant women decreases morbidity and improves growth of their infants during the first year of life. DESIGN: Women from a rural area in West Java, Indonesia, were randomly assigned on an individual basis to double-blind supplementation once weekly from approximately 18 weeks of pregnancy until delivery. Supplementation comprised 120 mg iron and 500 microg folic acid with or without 4800 RE vitamin A. Their newborn infants were followed up during the first year of life: weight, length, morbidity and food intake were assessed monthly. RESULTS: Infants whose mothers had taken vitamin A supplements during pregnancy had similar weight, length, weight gain and growth as their counterparts during the follow-up period. The proportions of infants with reported symptoms of morbidity were similar in the vitamin A plus iron group and the iron group. In addition immunisation coverage and feeding mode did not differ between the groups. All infants were breast-fed, but exclusive breast-feeding rapidly declined at 4 months of age. Infants with serum retinol concentrations >0.70 micromol/l increased their weight and length more during the first 6 months of life and had higher weight-for-age Z-scores during the first year of life than infants with serum retinol concentrations 相似文献   

Randomized controlled safety and efficacy trial of 2 vitamin A supplementation schedules in Tanzanian infants

BACKGROUND: Vitamin A supplementation reduces morbidity and mortality in children living in areas endemic for vitamin A deficiency. Routine vitamin A supplementation usually starts only at age 9 mo, but high rates of illness and mortality are seen in the first months of life. OBJECTIVE: The objective of the study was to evaluate the safety and efficacy of vitamin A supplementation at the same time as routine vaccination in infants aged 1-3 mo. DESIGN: We recruited 780 newborn infants and their mothers to a randomized double-blind controlled trial in Ifakara in southern Tanzania. In one group, mothers received 60,000 microg vitamin A palmitate shortly after delivery, and their infants received 7500 microg at the same time as vaccinations given at approximately 1, 2, and 3 mo of age. In the other group, mothers received a second 60,000-microg dose when their infant was aged 1 mo, and their infants received 15,000 microg at the same time as the routine vaccinations. VAD was defined as a modified relative dose-response test result of >or=0.060. RESULTS: High-dose vitamin A supplementation was well tolerated. The relative risk of VAD at 6 mo in the high-dose group compared with the lower dose group was 0.91 (95% CI: 0.76, 1.09; P=0.32). Serum retinol and incidence of illness did not differ significantly between the 2 groups. Some vitamin A capsules degraded toward the end of the study. CONCLUSIONS: Doubling the doses of vitamin A to mothers and their young infants is safe but unlikely to reduce short-term morbidity or to substantially enhance the biochemical vitamin A status of infants at age 6 mo. The stability of vitamin A capsules merits further investigation.     

补充维生素A与铁对改善学龄前儿童贫血和免疫功能的影响

目的为观察学龄前儿童亚临床维生素A(VA)缺乏状态缺铁时,机体免疫功能的变化以及VA与铁同时补充对改善儿童铁营养状况和免疫功能的影响.方法检测北京农村270名3～7岁儿童血清VA含量和血红蛋白(Hb)、血清铁(SI)、运铁蛋白饱和度(TS)及血清铁蛋白(SF)后,将其分为正常、低 VA、低铁和低VA低铁4组,每组选40人,检测血清免疫球蛋白IgA、IgG、IgM 与白细胞介素-2(IL-2).然后将低VA低铁组儿童随机分为补铁组 (每日口服相当于30 mg元素铁的硫酸亚铁,连续8周)和补VA+铁组(口服VA胶丸12 500 IU /次,2次/周,连续8周;口服铁量同补铁组,连续8周),分别进行干预.干预后重复检测血清VA、血液铁生化指标和以上免疫指标,进行两组间比较,并与干预前比较. 结果低VA低铁组儿童血清IgM为(1 260±310) mg/L显著高于正常组的(1 0 7 0±170) mg/L.对其实施VA+铁联合干预后,血清TS为(26.5±8.6)%,明显高于补铁前的(16.2±1.6)%和单纯补铁组的(22.3±3.8)%;IL-2在VA与铁同时补充后为(2 78.9±117.7) ng/L,显著高于补充前的(161.6±90.3) ng/L和单纯补铁组的(189 .5 ±89.3)ng/L的水平;其他铁生化指标和免疫指标无明显变化.结论对存在亚临床VA缺乏状态的缺铁儿童实施一定剂量的VA+铁联合干预,对改善机体铁营养状况和免疫功能有明显作用.