Marginal Vitamin A Deficiency Research Articles

High prevalence of xerophthalmia linked to socio-demographic and nutritional factors among vitamin A-deficient rural primary schoolchildren in Malaysia

Vitamin A deficiency (VAD) remains a major health issue in developing nations, contributing to preventable childhood blindness. However, there is lack of recent data on xerophthalmia, especially among school-aged children in Malaysia. We hypothesized that xerophthalmia persists among rural schoolchildren in Malaysia and potentially associated with socio-demographic status and malnutrition. We conducted a cross-sectional study on 596 schoolchildren (8-12 years) from ten rural primary schools located in five states across Malaysia. Children meeting the criteria for xerophthalmia assessment included those diagnosed with vitamin A deficiency (VAD) (plasma retinol < 0.70 µmol/L) and marginal VAD (plasma retinol 0.70 to < 1.05 µmol/L). The overall prevalence of xerophthalmia was 48.8%, with the most common ocular sign being conjunctival xerosis (38.9%). The occurrence of xerophthalmia was negatively associated with retinol-binding protein 4 (RPB4) (P=0.003), alpha-carotene (P=0.04), hemoglobin (P=0.004), weight (P=0.02), body mass index (BMI) (P=0.04) and WAZ (weight-for-age z-score) (P=0.04) status. Based on multivariate logistic regression analysis, a higher risk of xerophthalmia was observed in boys (Adjusted odd ratio [AOR]: 1.7, 95% confidence interval [CI]: 1.2-2.5) and Orang Asli (OA, indigenous) schoolchildren (AOR: 2.0, 95% CI: 1.3-3.0), while schoolchildren with overweight/obesity status (AOR: 0.5, 95% CI: 0.3-0.8) were associated with a reduced risk of xerophthalmia. The present study unveils a high prevalence of xerophthalmia among vitamin A-deficient primary schoolchildren in rural areas of Malaysia, especially among the indigenous community. The identified socio-demographic and nutritional factors associated to xerophthalmia would facilitate the implementation of more targeted interventions in addressing these issues.

Relationship of Vitamin A and Thyroid Function in Individuals With Obesity and After Laparoscopic Sleeve Gastrectomy.

Vitamin A deficiency (VAD) occurs in obesity and may be associated with thyroid dysfunction. We aimed to investigate the association of VA with thyroid function in obesity and after laparoscopic sleeve gastrectomy (LSG). Nine hundred and seventy-six obese subjects were enrolled for this study and were divided into VAD, marginal vitamin A deficiency (MVAD), and vitamin A normal (NVA) groups. VAD was defined as VA ≤ 200 ng/ml, MVAD was defined as VA > 200 but <300 ng/ml, and NVA was defined as VA ≥ 300 ng/ml. Thyroid function was compared among groups and the relationship of VA and thyroid function was analyzed. Two hundred and forty-four of the 976 obese subjects underwent LSG, and the change in thyroid function and VA at 3, 6, and 12 months after surgery was measured. Results showed that 37% of all the subjects had subclinical hypothyroidism (SH), and the SH group had lower VA levels than the non-SH group (P = 0.008). Forty-nine percent of all the subjects had MVAD, 9% had VAD, while the MVAD or VAD group had lower FT4 than the NVA group (P = 0.005 and P = 0.001). The VAD group also had higher TSH than NVA group (P = 0.037). VA was significantly negatively associated with TSH (r = −0.151, P = 0.006) and positively associated with FT4 (r = 0.228, P < 0.001). TSH was significantly decreased at 3, 6, and 12 months (3M: from 4.43 ± 2.70 to 2.63 ± 1.46 mU/l, P < 0.001; 6M: from 4.43 ± 2.70 to 3.84 ± 2.34 mU/l, P = 0.041; 12M: from 4.43 ± 2.70 to 2.85 ± 1.68 mU/l, P = 0.024). After LSG surgery, VA levels were slightly increased, when compared to pre-surgery levels, at 3, 6, and 12 months (3M: from 262.57 ± 68.19 to 410.33 ± 76.55 ng/ml, P = 0.065; 6M: from 262.57 ± 68.19 to 281.36 ± 93.23 ng/ml, P = 0.343; 12M: from 262.57 ± 68.19 to 300.37 ± 86.03 ng/ml, P = 0.083). SH group also had lower TSH and higher VA than the non-SH group at 3 months post-surgery [TSH: −1.4(−2.3, −0.3) vs. −0.2(−0.8, −0.2) mU/l, P < 0.001; VA: 163.99 ± 32.58 vs. 121.69 ± 27.59 ng/ml, P = 0.044]. In conclusion VA, which is related to thyroid hormone production, protects against thyroid dysfunction in obese subjects. The improvement of thyroid function in subjects with SH after LSG may be related to the increased VA levels observed post-surgery.Clinical Trial RegistrationClinicalTrial.gov ID: NCT04548232.

Vitamin A status and its hematological correlates among preschool children in Beijing, China.

Vitamin A is vital for the growth and health of children. This study aimed to estimate the current vitamin A status and the prevalence of vitamin A deficiency (VAD) among preschool children and explore the correlation between serum vitamin A concentration and changes in hematological parameters. The study included 697 children aged 1-6 years, presenting for routine checkups at the Department of Pediatrics, Peking University Shougang Hospital, Beijing, from April 2017 to December 2020. We obtained the complete laboratory test data of 630 children. The mean serum vitamin A concentration among preschool children was 0.29±0.08 mg/L, with a median of 0.29 mg/L. The proportion of children with VAD and marginal VAD (MVAD) was 9.84% and 43.49%, respectively. The highest prevalence of VAD and MVAD was in the 3- to 4-year age group. Compared with the normal vitamin A serum concentration group, other groups had lower mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and higher red blood cell distribution width. The mean serum vitamin A concentration among anemic children was significantly lower (0.27±0.07 mg/L) than among those children who were not anemic (p<0.05). VAD constitutes a public health problem in northern China. The prevalence of VAD is highest, and the serum vitamin A concentration was the lowest among preschool children aged 3-4 years. Vitamin A serum concentration was associated with red blood cell indices. We should attach more importance to those children aged 3-4 years.

Serum Vitamin A Nutritional Status of Children and Adolescents Aged 6-17 Years - China, 2016-2017.

Summary What is already known on this topic? Vitamin A deficiency (VAD) in children is still a global public health problem, which needs continuous monitoring and timely intervention. What is added by this report? Using surveillance data from China Nutrition and Health Surveillance of Children and Lactating Mothers in 2016−2017, the prevalence of VAD and marginal deficiency was 0.96% and 14.71%, respectively. The vitamin A nutritional status of children and adolescents from urban areas and those aged 12−17 years were better than those from rural areas and aged 6−11 years. What are the implications for public health practice? Marginal VAD was a major form of VAD in Chinese children. The monitoring of vitamin A status in key populations should be continuously strengthened, and the public should be encouraged to consume foods rich in vitamin A or vitamin A supplements.

Metabolomics Reveals Altered Hepatic Bile Acids, Gut Microbiome Metabolites, and Cell Membrane Lipids Associated with Marginal Vitamin A Deficiency in a Mongolian Gerbil Model.

This study is designed to provide a broad evaluation of the impacts of vitamin A (VA) deficiency on hepatic metabolism in a gerbil model. After 28 days of VA depletion, male Mongolian gerbils (Meriones unguiculatus) are randomly assigned to experimental diets for 28 days. Groups are fed a white-maize-based diet with ≈50µL cottonseed oil vehicle either alone (VA-, n=10) or containing 40µg retinyl acetate (VA+, n=10) for 28 days. Liver retinol is measured by high-performance liquid chromatography. Primary metabolomics, aminomics, lipidomics, bile acids, oxylipins, ceramides, and endocannabinoids are analyzed in post-mortem liver samples by liquid chromatography-mass spectrometry. Liver retinol is lower (p<0.001) in the VA- versus VA+ group, with concentrations indicating marginal VA deficiency. A total of 300 metabolites are identified. Marginal VA deficiency is associated with lower bile acids, trimethylamine N-oxide, and a variety of acylcarnitines, phospholipids and sphingomyelins (p<0.05). Components of DNA, including deoxyguanosine, cytidine, and N-carbomoyl-beta-alanine (p<0.05), are differentially altered. Hepatic metabolomics in a marginally VA-deficient gerbil model revealed alterations in markers of the gut microbiome, fatty acid and nucleotide metabolism, and cellular structure and signaling.

Interaction between dietary vitamin A, gut microbes, and host vitamin A status

Micronutrient deficiency during childhood, impairs microbiome development and establishment, ultimately affecting nutrient absorption and promoting inflammatory responses, especially in the gut, in a sort of vicious cycle1. Vitamin A is an essential micronutrient that regulates many critical biological functions, such as vision, reproduction and immunity, and that more generally contributes to the integrity of the epithelia by modulating cellular proliferation and differentiation 2. Vitamin A‐deficiency (VAD) is an overwhelming and still intractable public health problem3. The essential nutrient vitamin A regulates intestinal functions by modulating inflammation, gut immunity, and intestinal cell proliferation. Thus, the vitamin A status has a profound impact on intestinal health and, indeed, VAD is often associated with pathological conditions of the gut. On the other hand, a healthy intestine is critical to support a “healthy” microbiome which in turn helps maintaining proper intestinal functions in a feedback loop.To gain further understanding of the complex interplay between vitamin A, host physiology and microbiome, we used Lrat−/−Rbp−/−mice as a model of marginal VAD 4, when maintained on a vitamin A‐sufficient diet, and of severe VAD when deprived of dietary vitamin A. Due to the absence of lecithin:retinol acyltransferase (LRAT) and retinol‐binding protein (RBP), these mice cannot store and mobilize, respectively, hepatic vitamin A towards the periphery of the body. Thus, they rely exclusively on dietary vitamin A to support vitamin A‐dependent functions4. At 6 weeks of age, Lrat−/−Rbp−/− and WT mice were placed on either vitamin A‐sufficient or ‐deficient diet for 4 weeks and then returned to the initial regular chow regimen for 1 week. Various tissues, including intestine, and feces were collected at different time points throughout the experiment. We confirmed that VAD impairs intestinal vitamin A homeostasis and barrier functions (reduced antimicrobial defense and mucus production; increased oxidative stress; leaky gut). Genomic sequencing of the fecal 16S RNA showed that fecal dysbiosis is concomitant with the VAD status rather than the dietary vitamin A content per se, even though the degree of deficiency (marginal vs severe) did not further affect the dysbiosis. Instead, a preliminary analysis of microbial functionalities showed a significant separation of the microbial populations between vitamin A sufficient, marginal VAD and severe VAD.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Marginal Vitamin A Deficiency Affects the Expression Levels and Localization of Retinoic Acid Receptor and Retinoid X Receptor in Rats Meibomian Gland

ABSTRACTPurpose: To assess the effects of marginal vitamin A deficiency (MVAD) on rat Meibomian gland morphology as well as retinoic acid receptor (RAR) and retinoid X receptor (RXR) amounts and localization.Methods: Eight adult female rats were randomized into MVAD and vitamin A normal (VAN) groups, and fed vitamin A-deficient and normal control diets, respectively, for 3 weeks before mating. At postnatal week 4 (P4w), eight newborn animals in both groups were euthanized, respectively. Then, serum retinol levels were analyzed. Meibomian glands from P4w animals were further assessed upon hematoxylin and eosin staining. RAR and RXR gene and protein expression amounts were detected by real time polymerase chain reaction (qRT-PCR), immunofluorescence and western blotting, respectively.Results: Secretory cell nuclei had reduced areas, while the multilayered squamous epithelium of the ductule was overtly thinner in MVAD rats compared with VAN animals. RXR-α showed highest mRNA amounts among all RA receptors; compared with control values, RXR-α showed overtly decreased mRNA amounts in animals with MVAD. In addition, compared with normal rats, MVAD rats had starkly lower RXR-α and RXR-γ expression levels. Furthermore, only the RXR-α protein was detected in the nucleus of cells forming the multilayered squamous epithelium of the ductule in VAN rats.Conclusion: RARs and RXRs may be involved in the regulation of Meibomian gland function. RXR-α and 9-cis RA signaling affects Meibomian gland function, and the mechanisms of retinoids on secretory cells and the ductule epithelium may differ.Abbreviations: MVAD: marginal vitamin A deficiency; RAR: retinoic acid receptor; RXR: retinoid X receptor; VAN: vitamin A normal; RA: retinoic acid; RAREs: retinoic acid responsive elements; HPLC: high performance liquid chromatography; atRA: all-trans retinoic acid; MGD: Meibomian gland dysfunction; CRABPs: cellular retinoic acid-binding proteins

The Prevalence of Vitamin A Deficiency in Chinese Children: A Systematic Review and Bayesian Meta-Analysis.

Vitamin A deficiency (VAD), a leading cause of preventable childhood blindness, has been recognized as an important public health problem in many developing countries. In this study, we conducted a systematic review to identify all population-based studies of VAD and marginal VAD (MVAD) in Chinese children published from 1990 onwards. Hierarchical Bayesian meta-regressions were performed to examine the effects of age, sex, setting and year on the prevalence of VAD and MVAD, separately. The estimated prevalence was applied to the Chinese pediatric population in the year 2015 to generate prevalence estimates of VAD and MVAD for defined age groups, with 95% credible intervals (CrIs). Fifty-four studies met the inclusion criteria. The prevalence of VAD and MVAD both decreased with increasing age, and rural children had a higher prevalence of VAD and MVAD than urban children. In 2015, the prevalence of VAD was 5.16% (95% CrI: 1.95–12.64) and that of MVAD was 24.29% (95% CrI: 12.69–41.27) in Chinese children aged 12 years and under. VAD remains a public health problem in China. Efforts to reduce VAD in younger children are needed, especially for those in rural areas.

Marginal Vitamin A Deficiency Exacerbates Memory Deficits Following Aβ1-42 Injection in Rats.

BackgroundAlthough clinical vitamin A deficiency (VAD), which is a public health problem developing throughout the world, has been well controlled, marginal vitamin A deficiency (MVAD) is far more prevalent, especially among pregnant women and preschool children in China. Increasing evidence suggests that VAD is involved in the pathogenesis of Alzheimer’s disease (AD). However, whether MVAD, beginning early in life, increases the risk of developing AD has yet to be determined.ObjectiveThe goal of this study was to investigate the long-term effects of MVAD on the pathogenesis of AD in rats.MethodAn MVAD model was generated from maternal MVAD rats and maintained with an MVAD diet after weaning. The males were bilaterally injected with aggregated amyloid β (Aβ)1–42 into the CA3 area of the hippocampus, and the AD-associated cognitive and neuropathological phenotypes were examined.ResultsWe found that MVAD feeding significantly aggravated Aβ1-42-induced learning and memory deficits in the Morris water maze test. MVAD did not induce the mRNA expression of retinoic acid receptors (RARs), a disintegrin and metalloprotease 10 (ADAM10) or insulin-degrading enzyme (IDE) in Aβ1-42-injected rats. Moreover, RARα and RARγ mRNA were positively correlated with ADAM10 mRNA, whereas RARβ mRNA was positively correlated with IDE mRNA.ConclusionOur study suggests that MVAD beginning from the embryonic period perturbs the AD-associated genes, resulting in an enhanced risk of developing AD.

Study on vitamin A nutritional status of Chinese urban elderly residents in 2010-2012

Objective: To assess the vitamin A nutritional status of the Chinese urban elderly population by analyzing serum retinol level in 2010-2012. Methods: Data were collected from the Chinese National Nutrition and Health Survey in 2010-2012. Using the multi-stage stratified cluster sampling method, serum samples from elderly residents aged ≥60 years old were obtained from 34 metropolis and 41 middle-sized and small cities. Demographic data were collected using a questionnaire survey. The serum retinol concentration was determined by high-performance liquid chromatography. Vitamin A deficiency (VAD) was determined using the World Health Organization guidelines. A total of 3 200 elderly residents were included in the study. The serum retinol levels and prevalence of VAD and marginal VAD were also compared. Results: The serum retinol concentration (P(50)(P(25)-P(75))) of Chinese urban elderly residents was 1.83 (1.37-2.39) μmoL/L. Compared with middle-sized and small cities (1.91 (1.47-2.48) μmol/L), the retinol level of senior citizens in metropolis (1.70 (1.25-2.25) μmol/L) was significantly lower (P<0.001). The serum retinol levels of elderly male (1.89 (1.37-2.47) μmoL/L) was significantly higher than that of female (1.80 (1.36-2.28) μmoL/L) (P=0.001). The serum retinol concentration was 1.87 (1.42-2.43), 1.78 (1.32-2.33), and 1.71 (1.24-2.24) μmol/L for 60-69, 70-79, and ≥80 years olds, respectively. The retinol level in elderly people ≥70 years olds was significantly lower than that of 60-69 years olds (P<0.001). The overall prevalence of VAD among Chinese urban elderly residents was 4.22% (135/3 200); 6.00% (81/1 350) for metropolis residents and 2.92% (54/1 850) for middle-sized and small city residents. The overall marginal VAD rate of Chinese urban elderly residents was 8.19% (262/3 200); 10.51% (142/1 350) for metropolis residents and 6.49% (120/1 850) for medium-sized and small city residents. The prevalence of VAD and marginal VAD for males was 3.87% (61/1 577) and 8.24% (130/1 577), respectively (P<0.05). The prevalence of VAD according to age group was 3.65% (72/1 975), 4.96% (50/1 008), and 5.99% (13/217), respectively(P=0.097). The prevalence of marginal VAD according to age group was 6.99% (138/1 975), 9.82% (99/1 008), and 11.52% (25/217), respectively(P=0.05). Conclusion: Chinese urban elderly residents showed various levels of VAD, although marginal VAD was quite common. As VAD was more common in metropolis residents and older residents, specific strategies should target these populations.

Marginal vitamin A deficiency facilitates Alzheimer's pathogenesis.

Deposition of amyloid β protein (Aβ) to form neuritic plaques in the brain is the unique pathological hallmark of Alzheimer's disease (AD). Aβ is derived from amyloid β precursor protein (APP) by β- and γ-secretase cleavages and turned over by glia in the central nervous system (CNS). Vitamin A deficiency (VAD) has been shown to affect cognitive functions. Marginal vitamin A deficiency (MVAD) is a serious and widespread public health problem among pregnant women and children in developing countries. However, the role of MVAD in the pathogenesis of AD remains elusive. Our study showed that MVAD is approximately twofold more prevalent than VAD in the elderly, and increased cognitive decline is positively correlated with lower VA levels. We found that MVAD, mostly prenatal MVAD, promotes beta-site APP cleaving enzyme 1 (BACE1)-mediated Aβ production and neuritic plaque formation, and significantly exacerbates memory deficits in AD model mice. Supplementing a therapeuticdoseof VA rescued the MVAD-induced memory deficits. Taken together, our study demonstrates that MVAD facilitates AD pathogenesis and VA supplementation improves cognitive deficits. These results suggest that VA supplementation might be a potential approach for AD prevention and treatment.

Prevalence and factors associated with vitamin A deficiency in children and adolescents

ObjectiveTo identify the prevalence and factors associated with vitamin A deficiency (VAD) in children and adolescents. MethodsThis was a cross‐sectional study involving 546 schoolchildren, aged between 7 and 14 years, of both genders, enrolled in public elementary schools. Blood was collected for measurement of serum retinol. The retinol concentration in the samples was determined by high performance liquid chromatography (HPLC). Data were collected on anthropometrics, dietary, demographic, and socioeconomic factors. Polytomous logistic regression was used to evaluate the associations of interest. ResultsApproximately 27.5% of the students had retinol values<30μg/dL. The multivariate analysis showed, after the appropriate adjustments, a positive and statistically significant association of moderate/severe VAD (OR=2.19; 95% CI 1.17 to 4.10) and marginal VAD (OR=2.34; 95% CI 1.47 to 3.73) with age<10 years. There was also association of VAD moderate/severe (OR=2.01; 95% CI 1.01 to 5.05) and borderline VAD (OR=2.14; 95% CI: 1.08 to 4.21) with the anthropometric status of underweight. Lower intake of retinol was detected among those with severe VAD. ConclusionVAD is a health concern among children and adolescents. Lower weight and younger schoolchildren had greater vulnerability to VAD.

Prevalence and factors associated with vitamin A deficiency in children and adolescents

ObjectiveTo identify the prevalence and factors associated with vitamin A deficiency (VAD) in children and adolescents. MethodsThis was a cross-sectional study involving 546 schoolchildren, aged between 7 and 14 years, of both genders, enrolled in public elementary schools. Blood was collected for measurement of serum retinol. The retinol concentration in the samples was determined by high performance liquid chromatography (HPLC). Data were collected on anthropometrics, dietary, demographic, and socioeconomic factors. Polytomous logistic regression was used to evaluate the associations of interest. ResultsApproximately 27.5% of the students had retinol values<30μg/dL. The multivariate analysis showed, after the appropriate adjustments, a positive and statistically significant association of moderate/severe VAD (OR=2.19; 95% CI 1.17 to 4.10) and marginal VAD (OR=2.34; 95% CI 1.47 to 3.73) with age<10 years. There was also association of VAD moderate/severe (OR=2.01; 95% CI 1.01 to 5.05) and borderline VAD (OR=2.14; 95% CI: 1.08 to 4.21) with the anthropometric status of underweight. Lower intake of retinol was detected among those with severe VAD. ConclusionVAD is a health concern among children and adolescents. Lower weight and younger schoolchildren had greater vulnerability to VAD.

Effect of marginal vitamin A deficiency during pregnancy on retinoic acid receptors and N-methyl- d-aspartate receptor expression in the offspring of rats

This study examined whether pregnancy-related marginal vitamin A deficiency (MVAD) influences postnatal development of retinoic acid receptors (RARs) and N-methyl- d-aspartate (NMDA) receptor subunit 1 (NR1) in hippocampus of rat pups. Sixteen female rats were randomized equally into control and MVAD groups. Dams and pups were fed with either a normal control diet or one deficient in vitamin A. Eight female pups in each group were killed at 1 day, 2 weeks, 4 weeks and 8 weeks after birth, respectively. Serum retinol levels were monitored. The messenger RNA (mRNA) and protein expressions and subcellular localization of RARα, RARβ and NR1 in postnatal hippocampus were detected. At 1 day, 2 weeks and 8 weeks after birth, serum retinol levels in the MVAD group were significantly lower than those in the control group. Results of Morris water maze test at 7 weeks of age showed that spatial learning and memory in the MVAD group were affected. Vitamin A deficiency resulted in decreased mRNA levels of RARα, RARβ and NR1 ( P<.05). The protein level of RARα and NR1 in the MVAD group was lower than that of the control group ( P<.05). There was no significant difference in RARβ between the groups ( P>.05). A mass of RARα and NR1 colocalized in hippocampal cell cytoplasm on postnatal day 1. Our data suggested that vitamin A deficiency in pregnancy may affect the postnatal expression of RARα and NR1, affecting learning and memory function in the hippocampus and synaptic plasticity of the calcium signaling pathway.

Use of bitot's spot in screening for Vitamin A deficiency in Nigerian children

A total of 2,905 children between 6 and 71 months of age were selected using a 2 stage stratified sampling method and screened for xerophthalmia using World Health Organisation (WHO) criteria and vitamin a deficiency (VAD) using serum retinol < 20 ìg/dl (low/marginal). Only 33 cases of xerophthalmia were seen representing a national prevalence of 1.1%. Only 8 children presented with Bitot’s spots (XIB) representing 0.3% of the total number of children screened for marginal VAD and 24.2% of xerophthalmic cases. Corneal xerosis (stage X2) was the commonest (0.8%) ocular presentation amongst the total number of children screened and also amongst cases of xerophthalmia where it was responsible for 66.7%. 3 children with VAD (serum retinol < 10 ìg/dl) presented with Bitot’s spot, corneal xerosis and corneal scar respectively. All of these 3 children were severely malnourished and sick while one of them was moribund. No cases of conjunctival xerosis (X1A), corneal ulcer (X3A) or keratomalacia (X3B) were encountered in the study. Corneal scars (XS) attributable VAD was responsible to 0.1%. Stages X3A (corneal xerosis) and XS(corneal scars attributable toVAD) of xerophthalmia were above the WHO cut-off points. The national prevalence of marginal VADdefined as serum retinol was 28.1%. Despite its low prevalence, Bitot’s spot can be a useful screening tool particularly in a fieldsurvey involving a large population of children because of the characteristic cluster distribution of VAD. The implication of this is thata single case of Bitot’s spot points to a whole community at risk of VAD.

Co-assessment of iron, vitamin A and growth status to investigate anemia in preschool children in suburb Chongqing, China

Anemia is a widespread public health problem, which is due to many factors, nutritional or non-nutritional. Iron, vitamin A and growth status were assessed to investigate anemia of preschool children in suburb Chongqing, China. A descriptive, cross-sectional survey was performed on 459 preschool children aged 2 to 7 years randomly chosen from the kindergartens in 6 suburban districts of Chongqing. Weight and height levels, hemoglobin, erythrocyte protoporphyrin, serum retinol, and ferritin concentrations were measured to evaluate the anthropometric and nutritional status. The rates of stunt, underweight, overweight, wasting, obesity, anemia, iron deficiency, vitamin A deficiency (VAD), and marginal VAD were 6.3%, 3.9%, 3.7%, 1.5%, 3.1%, 23.5%, 15.0%, 6.3% and 25.9%, respectively. Serum retinol concentration was significantly lower in children with anemia than in those without anemia (P=0.003), and the retinol concentration was associated with hemoglobin (Pearson's correlation coefficient, r=0.22, P<0.01). Children with VAD had a significantly increased risk for anemia (odds ratio, 2.56; 95% confident interval, 1.15-5.70). In all 108 children with anemia, only 42 were related to VAD and 12 related to iron deficiency, suggesting that almost half of the anemia children cannot be explained solely by iron deficiency or VAD. Vitamin A and iron deficiency are still public health problems in some localities of China. Public health interventions in anemia control should be used to eliminate deficiencies of vitamin A, iron, and other micronutrients by deliberate supplementation. Attention must be paid to such deficiencies in high-risk groups, especially in preschool children.

Marginal Vitamin A Deficiency Affects Lung Maturation in Rats from Prenatal to Adult Stage

Mild or marginal vitamin A deficiency (MVAD) is still a serious and widespread public health problem in pregnant women and children in developing countries. This study investigated rat lung maturation from prenatal to adult stage during pregnancy and postnatal MVAD and the recovery after postnatal vitamin A supplementation (VAS). Adult female rats and their offspring were randomized into three groups. 1. the mothers and offspring received a normal diet.2. MVAD: The mothers and offspring received a MVAD diet.3. VAS: the mothers received MVAD diet till parturition, and then received the normal diet. The offspring of the VAS group were given low-dose vitamin A from postnatal day 1 to day 7 and received the normal diet after weaning. The lung development, structure, and collagen and elastic fiber of offspring were monitored by morphometric analysis at age 1 d, 2 and 8 wk, respectively. Lower body weight, lung weight, reduced numbers of alveoli and total alveolar surface area as well as increased alveoli septa thickness was observed in MVAD compared to that in the control animals. Increased collagen deposits and decreasing elastic fiber were found in MVAD rats. However, all of these were significantly improved in VAS-treated animals. These data suggest that the rat lung is sensitive to MVAD during the developing stage. Early postnatal vitamin A supplementation can partially restore the normal lung structure.

A new approach to the assessment of marginal vitamin A deficiency in children in suburban Guwahati, India: hydrolysis of retinoyl glucuronide to retinoic acid

The objective of the present study was to determine marginal vitamin A deficiency (VAD) by testing the hydrolysis of retinoyl glucuronide (RAG) to retinoic acid (RA) in children. Previous studies in rats showed that hydrolysis occurred when rats were vitamin A deficient. Children (n 61) aged 3-18 years, were divided into two groups, I and II. Blood was collected from the children in Group I (n 19) who were not dosed with RAG. Children in Group II (n 42) were administered all-trans retinoyl glucuronide (RAG) orally, and blood was collected 4 h after the dose. All serum samples were analysed for retinoids and carotenoids. RA was detected in serum only when serum retinol was < 0.85 micromol/l. Thus, hydrolysis of RAG to RA occurred in children with VAD or marginal VAD. Serum retinol was < 0.35 micromol/l in twenty-one children, 0.35-0.7 micromol/l in twenty-three children, 0.7-0.9 micromol/l in eleven children and >1 micromol/l in six children. Mean serum retinol in sixty-one children was 0.522 (sd 0.315) micromol/l. Mean beta-carotene (0.016 (sd 0.015) micromol/l) was far below normal compared to the level of lutein (0.176 (sd 0.10) micromol/l) in sixty-one children. A low beta-carotene level might be due to a low intake of carotene but high demand for vitamin A. The RAG hydrolysis test may prove to be a useful approach for the determination of marginal VAD with no clinical or subclinical signs of VAD. High prevalence of VAD amongst certain communities in Assam cannot be ruled out.

EFFECTS OF MARGINAL VITAMIN A DEFICIENCY ON LONG-TERM POTENTIATION IN YOUNG RATS

INTRODUCTION: Vitamin A is an essential micronutrient for brain development. Marginal vitamin A deficiency (MVAD) remains a subclinical public health problem in children, but little is known about the mechanism by which it affects brain development beginning from embryonic period and early postnatal period. OBJECTIVE: The objective of this study was to study the effects of MVAD on the hippocampal CA1 long-term potentiation (LTP) in young rats. METHODS: The MVAD group was fed a vitamin A–deficient diet (400 IU/kg vitamin A), and the control group was fed a vitamin A–sufficient diet (6500 IU/kg vitamin A) at 3 weeks before coitus. Serum vitamin A was assessed by high-performance liquid chromatography. Hippocampal CA1 LTP was detected by electrophysiologic technique, and the ultrastructure of synapses was observed by electron microscope. RESULTS: The changes of field excitatory postsynaptic potentials slope (25.4% ± 2.01%) in MVAD rats aged 7 weeks was much lower than that in the control group (57.5% ± 8.6%). The changes of slope of field excitatory postsynaptic potentials induced by MVAD in young rats could be replenished after addition of retinoic acid (RA); however, LTP impairment was observed again after addition of RA antagonist into the solution of the control group. No differences of LTP were found after addition of FeSO4 or ZnSO4. The curvature of the synaptic interface of the MVAD group was less than that of the MVAD group that was supplemented with RA and of the control group. CONCLUSIONS: MVAD during the embryonic and early postnatal period can directly impair the hippocampal CA1 LTP of young rats.

EFFECTS OF VITAMIN A ON LUNG DEVELOPMENT IN THE RAT FROM EARLY AGE TO ADULTHOOD

INTRODUCTION: Epidemiologic studies show that nutritional deficiency can alter lung development and have later adverse effects on lung function and respiratory health. Vitamin A is an important nutrient and is considered important in lung development and maturation. Additional studies are required to address whether vitamin A deficiency adversely affects lung development from early age to adulthood and whether such effects can be blocked or reversed. OBJECTIVE: Our aim was to study the effect of vitamin A on lung development in the rat from early age to adulthood. METHODS: Female rats were divided into control, marginal vitamin A deficiency (MVAD), and vitamin A intervention (VAI) groups. Control dams and pups were fed a normal diet (6500 U/kg vitamin A). MVAD rats were fed an MVAD diet (400 U/kg vitamin A). VAI rats were fed an MVAD diet until the birth of the pups and thereafter were fed with normal diet while the pups were given vitamin A through intragastric administration. All pups were killed at 8 weeks of age. Blood serum vitamin A levels were measured. Lungs were weighed and stained for light microscopy. RESULTS: The vitamin A level of the MVAD group was lower than that of the control group. Lung weight of MVAD rats was lower than that of the controls. Morphometric measurements showed that the alveolar number in MVAD rats was less than that of the controls, and alveolar septa were thicker than those of the controls. All results in VAI group were better than those in the MVAD group and showed no difference from the controls. CONCLUSIONS: Vitamin A status in early life can affect the lung development from early age to adulthood. Such effects can be reversed by dietary intervention after birth.