Retinol Deficiency Research Articles

Both human immunodeficiency virus–infected and human immunodeficiency virus–exposed, uninfected children living in Brazil, Argentina, and Mexico have similar rates of low concentrations of retinol, β-carotene, and vitamin E

Our objective was to describe the prevalence of low concentrations of retinol, beta-carotene, and vitamin E in a group of human immunodeficiency virus (HIV)-infected Latin American children and a comparison group of HIV-exposed, uninfected children. Our hypothesis was that the rates of low concentrations of these micronutrients would be higher in the HIV-infected group than those in the HIV-exposed, uninfected group. This was a cross-sectional substudy of a larger cohort study at clinical pediatric HIV centers in Latin America. Serum levels of micronutrients were measured in the first stored sample obtained after each child's first birthday by high-performance liquid chromatography. Low concentrations of retinol, beta-carotene, and vitamin E were defined as serum levels below 0.70, 0.35, and 18.0 micromol/L, respectively. The population for this analysis was 336 children (124 HIV-infected, 212 HIV-exposed, uninfected) aged 1 year or older to younger than 4 years. Rates of low concentrations were 74% for retinol, 27% for beta-carotene, and 89% for vitamin E. These rates were not affected by HIV status. Among the HIV-infected children, those treated with antiretrovirals were less likely to have retinol deficiency, but no other HIV-related factors correlated with micronutrient low serum levels. Low concentrations of retinol, beta-carotene, and vitamin E are very common in children exposed to HIV living in Brazil, Argentina, and Mexico, regardless of HIV-infection status.

Impact of a Multiple-micronutrient Fortified Salt on the Nutritional Status and Memory of Schoolchildren

This study was conducted to test the efficacy of a multiple micronutrient-fortified cooking salt. A randomized controlled trial with a pre- and post-test design was used to study children 5 to 18 years of age, with an experimental (n=213) and control group (n=189). The children were sampled from 3 residential schools and were studied for 9 months. The experimental group received a multiple micronutrient-fortified salt containing vitamins A, B(1), B(2), B(6), B(12), as well as folic acid, niacin, iron, iodine, and zinc. The control group received iodized salt. Biochemical measurements [hemoglobin, serum ferritin (SF), serum transferrin receptor (sTfR), C-reactive protein (CRP), alpha-1 acid glycoprotein (AGP), serum retinol, serum vitamin B(12), serum folic acid, serum zinc, and urinary iodine (UI)] were measured at baseline and post-intervention. Hemoglobin was measured in all the children three times during the study period, while the remaining biochemical measurements were performed in a subsample of children. Children between 11 and 18 years of age were given cognitive tests to assess memory and attention. There was a significant improvement (p<0.05) in all the biochemical measurements and memory tests in the experimental group when compared with the control group. Post-intervention in the experimental group, the increase in hemoglobin was 0.67 g/dL (p<0.05). Iron status and body iron stores increased significantly (p<0.05) in the experimental group compared to the control group, while serum zinc increased by 50 mug/dL (p<0.05), and the prevalence of retinol deficiency decreased from 57.1 % at baseline to 16 % post-intervention (p<0.05). The multiple micronutrients from the multiple micronutrient-fortified cooking salt were absorbed in the children and helped in combating micronutrient deficiencies.

Comparative effects of β-carotene and fucoxanthin on retinol deficiency induced oxidative stress in rats

This study aimed at comparing antioxidant potential of fucoxanthin (FUCO) with beta-carotene in relieving lipid peroxidation (Lpx) caused by retinol deficiency (RD) in rats. RD rats (n = 45) were fed a dose of either beta-carotene (0.81 mumol) or FUCO (0.83 mumol). Plasma and liver lipid peroxide levels and activity of antioxidant enzymes catalase (CAT) and glutathione transferase (GST) were measured for 8 h. Results revealed that RD increased (P < 0.05) Lpx in plasma and liver by 34.3% and 19.4%, while the CAT activity in plasma (89%) and liver microsomes (91%) and GST in liver homogenate (31%) and liver microsomes (30%) were decreased (P < 0.05) compared to control (rats fed basal diet). FUCO suppressed (P < 0.05) the Lpx level by 7-85% (plasma) and 24-72% (liver) as compared to beta-carotene (51-76%, 33-65%) over a period of 8 h. The activity of CAT in plasma and liver microsomes was higher (P < 0.05) in FUCO (90-95%, 85-93%) and beta-carotene (87-96%, 79-91%) groups as compared to RD group. Similarly, the activity of GST in liver and its microsomes was also elevated (P < 0.05) in FUCO (44-51%, 22-51%) and beta-carotene (19-54%, 30-43%) groups as compared to RD group. Results demonstrate that FUCO has greater potential than beta-carotene in modulating Lpx, CAT, GST in plasma and liver of RD rats.

Fucoxanthin restrains oxidative stress induced by retinol deficiency through modulation of Na+K+-ATPase and antioxidant enzyme activities in rats

Fucoxanthin restrains oxidative stress induced by retinol deficiency through modulation of Na+K+-ATPase and antioxidant enzyme activities in rats

Fucoxanthin restrains oxidative stress induced by retinol deficiency through modulation of Na+Ka+-ATPase and antioxidant enzyme activities in rats

Retinol deficiency is a major public health problem world wide, affecting children and women, in particular. It causes a variety of disorders in the body affecting various cellular functions. To study the effect of fucoxanthin (FUCO), a non-provitamin-A carotenoid in comparison with retinol (ROH) on changes in antioxidant molecules, lipid peroxidation and membrane bound enzymes in tissue and microsomes, induced by ROH deficiency in rats. After induction of ROH deficiency by feeding a diet devoid of ROH for 8 weeks, rats were divided into two groups (n = 20/group) and administered orally a dose of either FUCO (0.83 micromol) or ROH (0.87 micromol). A group of ROH deficient rats (n = 5) and rats (n = 5) fed with ROH sufficient diet was considered as baseline and control groups respectively. Over a period of 8 h, activity of catalase (CAT), glutathione transferase (GST), level of lipid peroxidation (LPx), fatty acids in plasma, liver and liver microsomes and activity of Na(+)K(+)-ATPase in liver microsomes were evaluated. ROH restriction increased LPx (P < 0.05) in liver (~19%) and plasma (~34%) while the activities of CAT (90 +/- 1%) and GST (17 +/- 4%) decreased compared to control. Significant elevation (91%) was observed for Na(+)K(+)-ATPase activity in liver microsomes of ROH deficient when compared to control group and levels were lowered on administration of ROH (37-69%) and FUCO (51-57%), towards control over a period of 8 h. ROH and FUCO suppressed (P < 0.05) the LPx level (%) in plasma (34-62, 7-85), liver homogenate (9-71, 24-72) and liver microsomes (83-92, 61-87), while the activities of CAT in plasma (89-97%, 91-95%) and liver microsomes (84-93%, 85-93%) and GST in liver homogenate (43-53%, 44-51%) and liver microsomes (36-52%, 22-51%) were increased (P < 0.05) compared to ROH deficient group. Results show that FUCO, a non-provitamin-A carotenoid protects cell membrane by modulating Na(+)K(+)-ATPase (51-57% lowering) and the activities of CAT and GST at the tissue and microsomal level which are affected by ROH deficiency. This may be due to its antioxidant nature. These in turn reduce LPx caused by ROH deficiency.

Retinol and Riboflavin Supplementation Decreases the Prevalence of Anemia in Chinese Pregnant Women Taking Iron and Folic Acid Supplements 3

In rural China, many pregnant women in their third trimester suffer from anemia (48%) and iron deficiency (ID; 42%), often with coexisting deficiencies of retinol and riboflavin. We investigated the effect of retinol and riboflavin supplementation in addition to iron plus folic acid on anemia and subjective well-being in pregnant women. The study was a 2-mo, double-blind, randomized trial. Subjects (n = 366) with anemia [hemoglobin (Hb) ≤ 105 g/L] were randomly assigned to 4 groups, all receiving 60 mg/d iron and 400 μg/d folic acid. The iron+folic acid (IF) group (n = 93) served as reference, the iron+folic acid+retinol group (IFA) (n = 91) was treated with 2000 μg retinol, the iron+folic acid+riboflavin group (IFB) (n = 91) with 1.0 mg riboflavin, and the iron+folic acid+retinol+riboflavin group (IFAB) (n = 91) with retinol and riboflavin. After the 2-mo intervention, the Hb concentration increased in all 4 groups (P < 0.001). The increase in the IFAB group was 5.4 ± 1.1 g/L greater than in the IF group (P < 0.001). The reduced prevalence of anemia (Hb < 110g/L) and ID anemia were significantly greater in the groups supplemented with retinol and /or riboflavin than in the IF group. Moreover, gastrointestinal symptoms were less prevalent in the IFA group than in the IF group (P < 0.05) and improved well-being was more prevalent in the groups receiving additional retinol and/or riboflavin than in the IF group (P < 0.05). Thus, a combination of iron, folic acid, retinol, and riboflavin was more effective than iron plus folic acid alone. Multimicronutrient supplementation may be worthwhile for pregnant women in rural China.

Retinol levels, iron status, malaria and intestinal parasites: TH1/TH2 cytokines relationship.

Introduction: Malaria infection, anaemia and intestinal parasitism, are important public health problems in Colombia. Available data suggests that these are not separate conditions, but interrelated. On the other hand, retinol supplementation successfully decreases mortality in children. In malaria endemic areas, this supplement reduces severe malaria in children, due to immune modulation by retinol. For example, retinoic acid induced a bias towards a TH2 immune response, an event that is associated with protection against severe anaemia. This review aimed at describing some relationships, reported in global biomedical literature, between retinol and malaria; retinol and anaemia; retinol, malaria and intestinal parasites; anaemia and malaria; and to how the TH1/TH2 cytokine pattern in individuals with malaria changes according to retinol supplementation. Methods: The following biomedical literature databases were consulted: Medline, Lilacs, Spingerlik, Md. Consultant, Web of Science, Ovid, Scient Direct, Ebsco and Cochrane. Information documenting prevalence of malnutrition, subclinical retinol deficiency, anaemia and malaria in Colombian children, as well as papers on the anti-infectious role of retinol were also. Results: A relationship between malaria and intestinal parasitic infections was reported. Some studies indicate that helminth infection predispose children to suffer malaria. On the other hand, these intestinal parasites have also been associated with anaemia and low retinol plasma concentrations, which in turn are associated with malaria. No co-relation regarding a simultaneous link between all these conditions, and the TH1/TH2 balance was observed. Conclusions: The study of associations between malaria, anaemia, intestinal parasite infections and low retinol level, with the TH1/TH2 cytokine response as centerpiece is essential to prevent or provide early treatment.

Relación entre vitamina A y alteraciones mucocutáneas y pilosas en niños de zonas palúdicas

Objetivo: conocer la clase y frecuencia de las alteraciones mucocutáneas y del cabello en niños de zonas maláricas de Antioquia (Colombia). Metodología: diseño experimental, balanceado, no ciego, con 93 niños con paludismo, seguidos durante 30 días. Resultados: 61% de los niños presentaron desnutrición crónica o global o ambas según la antropometría. Antes del tratamiento hubo alteraciones de la piel (41%), mucosa labial (12%), mucosa oral (2%), lengua (15%) y cabello (16%). El día 30 hubo mejoría en todos estos sitios corporales, excepto en la piel (alteraciones: 42%). El retinol plasmático fue menor de 20 ìg/dL en 56,5% (el día 1, cuando tenían malaria) y en 4,5% el día 30 (sin paludismo). A lo largo del seguimiento el retinol (ìg/dL) fue de 19,1 ± 6,8 el día 1; 32,6 ± 7,4 el día 8 y 31,2 ± 7,9 el día 30. El estado de la piel, las mucosas labial y bucal, la lengua y el cabello no se asoció con el retinol en los días 1 y 30, excepto el del cabello al día 30: 50% con retinol por debajo de 20 ìg/dL no tenían el cabello sano, comparados con 9% de los que tenían el retinol en 20 o más ìg/dL; tampoco se asoció con el riesgo de desnutrición, excepto por la asociación entre piel alterada y desnutrición crónica + global: 60% de los niños con piel anormal tenían desnutrición crónica + global, contra 20% de los que tenían la piel normal que presentaron esa desnutrición. Conclusiones: fueron muy frecuentes las alteraciones mucocutáneas y capilares en estos niños de zonas maláricas de Antioquia, quienes además presentaron elevada prevalencia de desnutrición crónica, global o ambas (61%) y baja frecuencia de déficit de retinol sérico (4,5%). En general las alteraciones mucocutáneas y capilares no se asociaron con el estado del retinol ni con el estado nutricional.

Disturbance of retinol transportation causes nitrofen-induced hypoplastic lung

Purpose Retinoids play a key role in lung development. Recent studies suggest that retinoid signalling pathway may be disrupted in the nitrofen model of congenital diaphragmatic hernia (CDH), but the exact mechanism is not clearly understood. We hypothesized that nitrofen interferes with cellular uptake of retinol during lung morphogenesis and therefore designed this study to examine total retinol levels in lung, liver, and serum, and the gene expression of main components of the retinoid pathway in the nitrofen model of CDH. Methods Pregnant rats were exposed to vehicle or 100 mg of nitrofen on day 9 of gestation. Term fetuses were divided in control and nitrofen with CDH and without CDH groups. Retinol levels in serum, lungs, and liver were measured using high-performance liquid chromatography. Reverse transcriptase–polymerase chain reaction was performed to evaluate the relative amount of cellular retinol-biding protein I, retinal dehydrogenase 1a2 and 1a3 (Aldh1a2 and Aldh1a3), retinoic acid receptors α and β (RAR α, RAR β), and retinoid X receptor α (RXR α) expression in the lung. Results Total retinol levels in the lungs were significantly lower in both nitrofen with CDH (1.78 ± 0.37 μg/g) and nitrofen without CDH (1.61 ± 0.24 μg/g) groups compared with controls (2.43 ± 0.31 μg/g) ( P < .001), whereas serum retinol levels were significantly higher in nitrofen with and without CDH groups (0.77 ± 0.13 and 0.75 ± 0.11 μg/g, respectively) compared with controls (0.58 ± 0.12 μg/g) ( P < .001). There was no significant difference in liver retinol levels between the 3 groups. Relative expression of cellular retinol-biding protein I, Aldh1a3, RAR α, RAR β, and RXR α were significantly up-regulated in the lungs of the nitrofen with CDH group (0.70 ± 0.15, 3.94 ± 0.91, 2.15 ± 0.47, 3.49 ± 1.00, 1.88 ± 0.42, respectively) and the nitrofen without CDH group (0.61 ± 0.14, 3.72 ± 0.31, 1.66 ± 0.20, 3.28 ± 1.02, 1.38 ± 0.24, respectively) compared with controls (0.43 ± 0.11, 2.71 ± 0.47, 0.79 ± 0.42, 1.85 ± 0.69, 0.57 ± 0.22, respectively) ( P < .05). Conclusion Our data clearly show that lung retinol storage is decreased in the nitrofen model of CDH. The associated increase in gene expressions of most downstream components of the retinoid signalling pathway may be a feedback reaction to the deficiency of lung retinol. These results suggest that nitrofen acts by interfering with the cellular uptake of retinol during lung morphogenesis resulting in pulmonary hypoplasia in this model.

Incidence of Vitamin Deficiency after Laparoscopic Roux-en-Y Gastric Bypass in a University Hospital Setting

Vitamin deficiency after gastric bypass surgery is a known complication. The purpose of this study was to measure the incidence of vitamin deficiency after laparoscopic Roux-en-Y gastric bypass in a university hospital setting. All patients who underwent laparoscopic Roux-en-Y gastric bypass from January 2002 to December 2004 and completed a 1- and 2-year follow-up after surgery were selected. Of the total 493 patients, 318 (65%) had vitamin results at 1-year follow-up. Of the 366 eligible for the 2-year follow-up, 141 (39%) had vitamin results. Patients were further grouped based on gender, race, and Roux limb length, and incidence of vitamin deficiencies were studied. The incidence of vitamin A (retinol) deficiency was 11 per cent, vitamin C was 34.6 per cent, vitamin D25OH was 7 per cent, vitamin B1 was 18.3 per cent, vitamin B2 was 13.6 per cent, vitamin B6 was 17.6 per cent, and vitamin B12 was 3.6 per cent 12 months after surgery. There was no statistical difference in the incidence of vitamin deficiencies between 1 and 2 years. In univariate and multivariate logistic regression of 1- and 2-year follow up, black patients (vitamins A, D, and B1 for 1 year and B1 and B6 for 2 years) and women (vitamin C at 1 year) were more likely to have vitamin deficiencies. Vitamin deficiencies after laparoscopic Roux-en-Y gastric bypass are more common and involve more vitamins, even those that are water soluble, than previously appreciated. Black patients tend to have more deficiencies than other groups. The bariatric surgeon should be committed to the long-term follow-up and care of these patients. Further prospective and randomized studies are necessary to provide appropriate guidelines for supplementation.

Molecular Screening for GS2 Lipase Regulators: Inhibition of Keratinocyte Retinylester Hydrolysis by TIP47

Retinoic acid at nanomolar concentrations modulates epidermal functions by serving as a transcription factor ligand. Under conditions of retinol sufficiency, it is imperative to limit retinoic acid biosynthesis from serum-derived retinol. In the epidermis, this is accomplished by esterifying retinol with long-chain fatty acids. Retinylester (RE) pools serve as a source of retinol for retinoic acid production under retinol deficiency and when required for proper differentiation. We have recently reported that GS2 lipase is expressed in keratinocytes and has the enzymatic properties of keratinocyte RE hydrolase. As GS2 lipase has a robust activity that can affect the intracellular retinol levels, we postulated that its activity must be regulated. Therefore, we screened keratinocyte cDNA expression libraries for the putative inhibitor. Herein, we report the identity of an inhibitor, TIP47, which prevents RE hydrolysis catalyzed by GS2 lipase and hormone-sensitive lipase. This protein was known to transport mannose-6-phosphate receptors from endosome to trans-Golgi and to be distributed between the cytoplasm and lipid droplets. Using a series of deletion mutants, we found two regions involved in the inhibitory activity. Residues within the carboxyl alpha3-alpha4 helices are essential in the context of the full-length protein. Residues within the amino-terminal also contribute depending on the context.

Recommended dose for repair of serum vitamin A levels in patients with HIV infection/AIDS may be insufficient because of high urinary losses

Objective Retinol deficiency is quite frequent in the population of human immunodeficiency virus (HIV)-infected individuals. Serum retinol levels of less than 1.05 μmol/L determine a 3.5 to five times higher death risk. However, studies evaluating the efficacy of retinol supplementation in HIV-seropositive individuals have reported conflicting results. The World Health Organization recommends the treatment of vitamin A deficiency in seropositive individuals in the same manner as for seronegative individuals, but clinical studies proving the efficacy of this scheme are lacking. The proposal of the present study was to assess the efficacy of supplementation with high retinol doses in HIV-infected patients with vitamin A deficiency. Methods Twenty-five adult HIV-seropositive individuals were monitored over a period of 9 months, with determination of serum and urinary retinol every 3 months. The subjects received retinol palmitate doses ranging from 300,000 IU to 600,000 IU. Patients whose retinol levels were higher than 1.60 μmol/L were only observed. Results Eighteen patients received supplementation during clinical monitoring. The dose of 600,000 IU induced a significant mean increase in serum levels of 0.47 μmol/L ( P = 0.049) within a period of three months. Those who received 300,000 IU presented a mean increase of 0.29 μmol/L. In contrast, the patients who did not receive replacement therapy presented a significant decrease ( P = 0.017) in serum retinol levels, with initial and final values of 1.77 μmol/L and 1.55 μmol/L. The individuals with the worst response to supplementation presented a higher urinary loss of retinol at the beginning of the study. Even with a mean retinol supplementation of 771,428 IU during the study period, six patients had marginal serum retinol levels at the end of the study. Conclusion We conclude that, in view of the high urinary loss of this nutrient, there is the need to redefine the ideal dose for the treatment of HIV-infected individuals.

Global effects of vitamin A deficiency on gene expression in rat liver: evidence for hypoandrogenism

Vitamin A (retinol) metabolites are ligands for transcription factors that regulate many genes. The liver is the main storage depot for retinol and plays a role in vitamin A homeostasis. To better understand the effects of vitamin A deficiency on liver gene expression, we produced retinol deficiency in male rats by feeding a diet low in retinol for 53 days after weaning and examined the effects on gene expression in liver using Affymetrix oligonucleotide microarrays. We detected expression of 41% of the 8799 probe sets represented on the RGU-34A GeneChips. Vitamin A deficiency resulted in major changes in liver gene expression: 805 genes (22% of all genes detected) differed at P≤.05 (false discovery rate <0.143). Genes involved in fatty acid metabolism, peroxisomal function, glycolysis, glutamate metabolism and the urea cycle were altered. The expression of many sexually dimorphic genes was altered toward a feminized or senescent pattern of gene expression in the liver. Retinol deficiency also produces a shift toward increased protein and fat catabolism and decreased fatty acid synthesis.

Biochemical basis for retinol deficiency induced by the I41N and G75D mutations in human plasma retinol-binding protein

Retinol-binding protein (RBP) is the retinol-specific carrier protein present in plasma, where it circulates almost entirely bound to thyroxine-binding transthyretin (TTR). Recently, depressed plasma retinol and RBP levels in carriers of the I41N and G75D RBP point mutations have been reported. We show here that although recombinant human N41 and D75 RBPs can form complexes with retinol and TTR in vitro, the retinol-mutated RBP complexes are significantly less stable than human normal holo-RBP, as revealed by the markedly facilitated retinol release by mutated holo-RBPs to phospholipid membranes, in accordance with the location of mutated residues inside the RBP retinol-binding cavity. Taken together, the data are consistent with the I41N and G75D point mutations being the cause of an altered interaction of retinol with RBP, resulting in a remarkably reduced stability of the retinol–RBP complex, which in turn can lead to the lowering of plasma retinol and RBP levels.

Níveis plasmáticos de vitamina A em crianças carentes com pneumonia na fase aguda e após recuperação

OBJETIVO: Comparar os níveis plasmáticos de retinol em crianças de baixo nível socioeconômico com pneumonia, antes e depois da resolução do processo infeccioso; investigar a associação entre os níveis plasmáticos de retinol, após a resolução da infecção, com algumas variáveis socioeconômicas, a condição nutricional e a gravidade da pneumonia. MÉTODOS: Estudo de coorte prospectivo desenvolvido com 40 crianças, hospitalizadas por pneumonia, na faixa etária de 6 meses a 5 anos. Foram avaliados o nível plasmático de retinol na fase aguda e após a resolução da infecção, a escolaridade do chefe da família, a renda per capita, o peso ao nascer, a condição nutricional, os níveis de hemoglobina e a gravidade da pneumonia. RESULTADOS: O valor médio de retinol plasmático após a resolução do processo infeccioso foi maior em relação à fase aguda da infecção (1,4±0,6 versus 1,7±0,6 µmol/l, p = 0,03). A freqüência de níveis inadequados de retinol (< 1,05 µmol/l) foi de 32,5 e 17,5% na fase aguda e na resolução do processo infeccioso, respectivamente. Não se verificou relação estatisticamente significante entre a deficiência retinol e as variáveis clínico-epidemiológicas estudadas. A pneumonia mais grave foi observada em 30/40 (75%) dos pacientes. Não houve diferença estatisticamente significante entre a inadequação dos níveis plasmáticos de retinol, após a resolução do processo infeccioso, com a gravidade da pneumonia (4/30 - 13,3% versus 3/10 - 30,0%, p = 0,34). CONCLUSÃO: Os níveis plasmáticos de retinol foram mais altos após a resolução do processo infeccioso em relação à fase aguda, não havendo associação com as variáveis clínico-epidemiológicas estudadas.

Plasma vitamin A levels in deprived children with pneumonia during the acute phase and after recovery

The aim of this study was to examine the plasma retinol of children in the acute phase of pneumonia and after recovery and to investigate the association between plasma levels of retinol after recovery with socioeconomic variables, nutritional status and severity of pneumonia. A prospective cohort study which included 40 low-income hospitalized children with pneumonia, aged 6 months to 5 years. We evaluated: plasma retinol level during the acute phase and after recovery, years of schooling of the head of the family, per capita income, birth weight, nutritional status, hemoglobin levels and severity of pneumonia. Mean plasma retinol levels were significantly higher after recovery than during the acute phase of infection (1.4+/-0.6 vs. 1.7+/-0.6 micromol/l, p = 0.03). The frequency of inadequate plasma retinol levels (< 1.05 micromol/l) was 32.5 and 17.5% for the acute phase and after recovery, respectively. There were no statistically significant associations between plasma retinol deficiency and the clinical and epidemiological variables studied. More severe pneumonia was observed in 30/40 (75%) of the patients. There was no statistically significant association between plasma retinol inadequacy after recovery and severity of pneumonia (4/30 - 13.3% vs. 3/10 - 30.0%, p = 0.34). Serum retinol levels were significantly higher after recovery than during the acute phase of pneumonia. There was no statistically significant association between the deficiency of serum retinol and the clinical and epidemiological variables studied.

Critical role for retinol in the generation/differentiation of angioblasts required for embryonic blood vessel formation.

Numerous studies demonstrate that vitamin A (retinol) deficiency causes abnormal cardiovascular morphogenesis. We evaluated the impact of retinol deficiency on the regulation of the numbers of endothelial cells and angioblasts (endothelial progenitors) produced during embryonic quail development. At the one-somite stage, there were no discernible differences in the mean number of endothelial cells or angioblasts in normal and retinol-deficient embryos. However, retinol-deficient embryos at the three-somite stage had an increase in the mean number of endothelial cells but no difference in the mean number of angioblasts. By contrast, retinol-deficient embryos at the five-somite stage have 61% of the normal number of endothelial cells and 12% of the normal number of angioblasts. Similarly, retinol-deficient embryos at the 10-somite stage had 71% and 60% of normal numbers of endothelial cells in capillary-like networks and the sinuses venosus, respectively. Furthermore, we show that retinol deficiency did not elicit a global reduction in mesodermal cell numbers but was specific to cells of the endothelial lineage. Taken together, our findings suggest that vascular abnormalities observed under conditions of retinol deficiency are due to reduction in the number of angioblasts and consequently an insufficiency in the number of endothelial cells required to build complex vascular networks.

Vitamin A status and nutritional intake of carotenoids of preschool children in Ijaye Orile community in Nigeria.

This study was carried out to determine the vitamin A status and nutritional intake of carotenoids of 213 children between the ages of 6 months and 6 years in a rural community in Nigeria. There were 109 males and 104 females. A total of 57 (26.8 per cent) children were deficient in serum retinol levels (< 10 microg/dl) while 102 (47.9 per cent) had low levels (10-19 microg/dl). The highest prevalence of serum retinol deficiency was in the 6-12 months age group, most of whom were breastfeeding and there was poor correlation between duration of breastfeeding and serum retinol levels. The prevalence of night-blindness was 1.5 per cent; however, none of the children had xerophthalmia. Chronically malnourished children had lower mean serum retinol levels than well nourished children. There was a high consumption of carotenoid-containing food, but despite this there was a high prevalence of vitamin A deficiency. We therefore suggest that measures to combat vitamin A deficiency should include vitamin A supplementation on a short-term basis. On a long-term basis parents should be educated on the importance of the consumption of locally available sources of provitamin A and pre-formed vitamin A rich foods, and the avoidance of overcooking. Parents should also be encouraged to grow more beta-carotene containing foods.

Micronutrient deficiency and its alleviation: The case of Malaysia

Since attaining independence in 1957, Malaysia has achieved marked socio‐economic development including advances made in the health care delivery system. Vital statistics over the decades showed much improvement in the health status of Malaysians in general. For example, the infant, toddler and maternal mortality rates have declined to levels reflective of developed countries namely, 9.5, 0.7 and 0.2 per 1,000 live births respectively in 1997. The nutritional status of Malaysians mirrors a society that is undergoing nutrition transition. Consequences of the dual burden of under‐ and over‐nutrition are evident in various age groups in rural and urban areas. Nutrition problems which persist include underweight and stunting in children, anaemia in young children, women and the elderly, iodine deficiency disorders in interior population groups in Sarawak and Sabah, folic acid deficiency among pregnant women, and subclinical retinol deficiency in young children. The Ministry of Health has played a pivotal role in implementing various nutrition intervention programmes towards the alleviation of these problems. These programmes will be elaborated.

Vitamin A deficiency and genital viral burden in women infected with HIV-1

The relation between vitamin A (retinol) deficiency and perinatal transmission of HIV-1, if it exists, might be mediated through an increased viral load in the mother's genital tract. To ascertain whether or not such an association is present, we measured the serum concentration of retinol with high performance liquid chromatography, and correlated the results with concurrent quantified HIV-1 RNA concentrations in cervicovaginal lavage fluid in 301 women infected with the virus. We noted no association between retinol status and genital HIV-1 load. Our findings lend support to those of studies that reported no association between retinol deficiency and perinatal HIV-1 transmission.