Predictors of serum retinol in children with shigellosis

Vitamin A biomarkers were associated with α(1)-acid glycoprotein and C-reactive protein over the course of a human norovirus challenge infection

Retinol binding protein (RBP) is used as a proxy for retinol in population-based assessments of vitamin A deficiency (VAD) for cost-effectiveness and feasibility. When the cut-off of < 0·7 μmol/l for retinol is applied to RBP to define VAD, an equivalence of the two biomarkers is assumed. Evidence suggests that the relationship between retinol and RBP is not 1:1, particularly in populations with a high burden of infection or inflammation. The goal of this analysis was to longitudinally evaluate the retinol:RBP ratio over 1 month of follow-up among fifty-two individuals exposed to norovirus (n 26 infected, n 26 uninfected), test whether inflammation (measured as α-1-acid glycoprotein (AGP) and C-reactive protein (CRP)) affects retinol, RBP and the ratio between the two and assess whether adjusting vitamin A biomarkers for AGP or CRP improves the equivalence of retinol and RBP. We found that the median molar ratio between retinol and RBP was the same among infected (0·68) and uninfected (0·68) individuals. AGP was associated with the ratio and RBP individually, controlling for CRP, and CRP was associated with both retinol and RBP individually, controlling for AGP over 1 month of follow-up. Adjusting for inflammation led to a slight increase in the ratio among infected individuals (0·71) but remained significantly different from the expected value of one. These findings highlight the need for updated recommendations from the WHO on a cut-off value for RBP and an appropriate method for measuring and adjusting for inflammation when using RBP in population assessments of VAD.

Consequences of Shigella infection in young children: a systematic review

OBJECTIVES

We conducted a systematic review of the longitudinal consequences of Shigella infection in children to inform the value proposition for an effective vaccine.

METHODS

We searched PubMed and Embase for studies published from January 01, 1980 to December 12, 2022 and conducted in low- and middle-income countries that included longitudinal follow-up after Shigella detection among children aged <5 years, irrespective of language. We collected data on all outcomes subsequent to Shigella detection, except mortality.

RESULTS

Of 2627 papers identified, 52 met inclusion criteria. The median sample size of children aged <5 years was 66 (range 5-2172). Data were collected in 20 countries; 56% (n = 29) of the publications included Bangladesh. The most common outcomes related to diarrhea (n = 20), linear growth (n = 14), and the mean total cost of a Shigella episode (n = 4; range: $ 6.22-31.10). Among children with Shigella diarrhea, 2.9-61.1% developed persistent diarrhea (≥14 days); the persistence was significantly more likely among children who were malnourished, had bloody stool, or had multidrug-resistant Shigella. Cumulative Shigella infections over the first 2 years of life contributed to the greatest loss in length-for-age z-score.

CONCLUSION

We identified evidence that Shigella is associated with persistent diarrhea, linear growth faltering, and economic impact to the family.

Investigation of Vitamin a and 25(OH)D3 Levels in Cattle with Pneumonia Detected Mycoplasma bovis

This study investigated the presence of Mycoplasma bovis in nasal swabs taken from cattle with pneumonia, to reveal the clinical and biochemical findings of positive animals, and determine the levels of vitamin A and 25(OH)D3. In the study were included 103 infected cattle and 10 healthy cattle, all aged 1-4 years, as the control group. Quantitative clinical evaluations and clinical examinations were performed on each animal, and 5 ml blood samples and nasal swabs were taken. Serum biochemistry, vitamin A and 25(OH)D3 levels were determined in both positive and control samples. The clinical signs were identified by qualitative scoring in M. bovis positive animals. Regarding the clinical findings, respiratory frequency, heart rate, and rectal temperature were significantly higher in positive than control group animals (p<0.001). Regarding the biochemistry findings, albumin (ALB) and glucose (GLU) levels were lower in cattle infected with M. bovis (p<0.001) whereas total protein (TP) and alkaline phosphatase (ALP) levels were higher (p<0.001). While serum 25(OH)D3 levels were lower in infected animals (p<0.001), there was no significant difference (p>0.05) in serum vitamin A levels. In this study, clinical findings in cattle naturally infected with M. bovis were expressed qualitatively and quantitatively. In addition, it has been revealed that the disease does not only cause lung involvement, but also causes changes in biochemical and vitamin levels. Although these parameters cannot be used as a biomarker in the diagnosis of pneumonia, they are thought to provide benefits in terms of diagnosis, treatment and prophylaxis in practice.

Frequency of Vitamin a Deficiency in Children Hospitalized for Pneumonia: An Integrative Review

Objective: To identify the frequency of vitamin A deficiency in children aged 6 months to 5 years hospitalized for pneumonia. Methods: An integrative literature review was carried out, where searches were made by two independent researchers, with no language limits or publication time in the databases PubMed, LILACS, Web of Science, Scopus and CINAHL, and in the gray literature-OpenGrey, Proquest and Google Scholar. In the eligibility phase, the screened studies were read in full and those that did not answer the research question were excluded. Methodological quality was assessed using the Downs & Black (1998) checklist. Results: 1642 articles were identified, after all stages of screening and selection, 10 studies were included, of which 5 were longitudinal, 4 were intervention and 1 transversal. All studies identified subclinical vitamin A deficiency in children hospitalized with pneumonia; the highest frequency of subclinical vitamin A deficiency was 93.2%. All studies evaluated showed frequencies of subclinical vitamin A deficiency >20%. Conclusion: There is a high frequency of subclinical vitamin A deficiency in children with pneumonia; these data need to be further explored in terms of their associations. For this reason, new studies that evaluate this topic are of fundamental importance.

Influence of Vitamin A supplementation on inflammatory biomarkers in adults: a systematic review and meta-analysis of randomized clinical trials

Vitamin A is an anti-oxidant which has been presumed to act as an anti-infective vitamin in many studies. This study aimed to evaluate the association between vitamin A supplementation and c-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) levels in randomized control trials (RCTs) studies on adults. A systematic search was performed on databases including PUBMED, SCOPUS, and the Cochrane library. The studies included were considered for data extraction and subsequently assessed for effect. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were evaluated. Among 13,219 articles 13 studies were included for analysis of CRP and TNF-α, as well as 9 studies included for IL-6 in quality and quantity. The pooled WMD analysis of CRP demonstrated that vitamin A supplementation significantly increased CRP concentration with (WMD: 0.84 mg/L; 95% CI 0.29-1.39, I² = 0.96.2% and p value < 0.003). However, there was no significant correlation between vitamin A supplementation and lower plasma TNF-α (p < 0.45)). Subgroup analysis by dosage demonstrate significant association between vitamin A supplementation and IL-6 in dosage with 50,000 with (WMD: - 1.53 mg/L; 95% CI - 2.36 to - 0.71, p value < 0.00001) as well as a negative significant association was seen at 44 weeks of supplementation with 50,000 IU/day retinyl palmitate and TNF-a in chronic hepatitis B conditions with (- 0.94 (- 1.19, - 0.69) p < 0.0001). The result of this study demonstrates that supplementation of vitamin A at low and high dosages for short and long durations increases the CRP plasma concentrations on adults and vitamin A supplementation decreases the TNF-α concentrations in chronic hepatitis B on adults. Therefore, there is an inverse association between vitamin A supplementation and plasma and fecal IL-6 concentrations in many infection conditions.

Essential metals, vitamins and antioxidant enzyme activities in COVID-19 patients and their potential associations with the disease severity

The role of micronutrient deficiency in the pathogenesis of COVID-19 has been reviewed in the literature; however, the data are limited and conflicting. This study investigated the association between the status of essential metals, vitamins, and antioxidant enzyme activities in COVID-19 patients and disease severity. We recruited 155 patients, who were grouped into four classes based on the Adults guideline for the Management of Coronavirus Disease 2019 at King Faisal Specialist & Research Centre (KFSH&RC): asymptomatic (N = 16), mild (N = 49), moderate (N = 68), and severe (N = 22). We measured serum levels of copper (Cu), zinc (Zn), selenium (Se), vitamin D₃, vitamin A, vitamin E, total antioxidant capacity, and superoxide dismutase (SOD). Among the patients, 30%, 25%, 37%, and 68% were deficient in Se (< 70.08 µg/L), Zn (< 0.693 µg/mL), vitamin A (< 0.343 µg/mL), and vitamin D₃ (< 20.05 µg/L), respectively, and SOD activity was low. Among the patients, 28% had elevated Cu levels (> 1.401 µg/mL, KFSH&RC upper reference limit). Multiple regression analysis revealed an 18% decrease in Se levels in patients with severe symptoms, which increased to 30% after adjusting the model for inflammatory markers. Regardless of inflammation, Se was independently associated with COVID-19 severity. In contrast, a 50% increase in Cu levels was associated with disease severity only after adjusting for C-reactive protein, reflecting its possible inflammatory and pro-oxidant role in COVID-19 pathogenesis. We noted an imbalance in the ratio between Cu and Zn, with ~ 83% of patients having a Cu/Zn ratio > 1, which is an indicator of inflammation. Cu-to-Zn ratio increased to 45% in patients with mild symptoms and 34%–36% in patients with moderate symptoms compared to asymptomatic patients. These relationships were only obtained when one of the laboratory parameters (lymphocyte or monocyte) or inflammatory markers (neutrophil-to-lymphocyte ratio) was included in the regression model. These findings suggest that Cu/Zn might further exacerbate inflammation in COVID-19 patients and might be synergistically associated with disease severity. A 23% decrease in vitamin A was seen in patients with severe symptoms, which disappeared after adjusting for inflammatory markers. This finding may highlight the potential role of inflammation in mediating the relationship between COVID-19 severity and vitamin A levels. Despite our patients’ low status of Zn, vitamin D₃, and antioxidant enzyme (SOD), there is no evidence of their role in COVID-19 progression. Our findings reinforce that deficiency or excess of certain micronutrients plays a role in the pathogenesis of COVID-19. More studies are required to support our results.

Vitamin A status, inflammation adjustment, and immunologic response in the context of acute febrile illness: A pilot cohort study among pediatric patients

BACKGROUND

Vitamin A is necessary for an adequate immune response to infections. Infection also alters vitamin A biomarkers, which interferes with assessment of vitamin A deficiency and thus impairs clinical management. Here we apply multiple strategies to adjust vitamin A biomarkers for inflammation during acute infection and evaluate associations between adjusted vitamin A status and immunologic response markers.

METHODS

We measured biomarkers in pediatric patients presenting with acute febrile illness in Guayaquil, Ecuador at paired acute and convalescent visits. Four adjustment strategies were applied to retinol-binding protein (RBP) concentrations: Thurnham correction factor (TCF), BRINDA regression correction (BRC), CRP-only adjustment factor (CRP), and proof-of-concept for a proposed interleukin 6 regression model (IL-6 RM). Adjusted RBP concentrations were compared between visits using the paired Wilcoxon signed-rank test. Multivariate regression analysis was used to assess associations between adjusted vitamin A status and immunologic response markers.

RESULTS

A sample of 57 participants completed the acute visit 1, and 18 of these individuals completed the convalescent visit 2. The IL-6 RM was the only strategy resulting in adjusted RBP concentrations that were not significantly different between paired visits (p = 0.20). Following RBP adjustment, 0.0% of participants were classified as vitamin A deficient (RBP ≤ 0.70 μmol/L) and 14.0% were classified as vitamin A insufficient (RBP ≤ 1.05 μmol/L). Adjusted vitamin A insufficiency was associated with an increase in macrophage inflammatory protein 1-alpha (MIP-1α, p = 0.03) and a pro-inflammatory immune response profile (p = 0.03) during the acute visit.

CONCLUSIONS

We introduce a strategy for adjusting vitamin A in the context of clinical illness based on IL-6 concentrations that will need to be validated in larger studies. Assessment of vitamin A during infection allows for further understanding of how vitamin A status modulates immunopathology and enables targeted strategies for vitamin A supplementation in the context of infection among children in settings with high burdens of undernutrition and infectious diseases.

Rubella Virus Infection, the Congenital Rubella Syndrome, and the Link to Autism

Rubella is a systemic virus infection that is usually mild. It can, however, cause severe birth defects known as the congenital rubella syndrome (CRS) when infection occurs early in pregnancy. As many as 8%-13% of children with CRS developed autism during the rubella epidemic of the 1960s compared to the background rate of about 1 new case per 5000 children. Rubella infection and CRS are now rare in the U.S. and in Europe due to widespread vaccination. However, autism rates have risen dramatically in recent decades to about 3% of children today, with many cases appearing after a period of normal development ('regressive autism'). Evidence is reviewed here suggesting that the signs and symptoms of rubella may be due to alterations in the hepatic metabolism of vitamin A (retinoids), precipitated by the acute phase of the infection. The infection causes mild liver dysfunction and the spillage of stored vitamin A compounds into the circulation, resulting in an endogenous form of hypervitaminosis A. Given that vitamin A is a known teratogen, it is suggested that rubella infection occurring in the early weeks of pregnancy causes CRS through maternal liver dysfunction and exposure of the developing fetus to excessive vitamin A. On this view, the multiple manifestations of CRS and associated autism represent endogenous forms of hypervitaminosis A. It is further proposed that regressive autism results primarily from post-natal influences of a liver-damaging nature and exposure to excess vitamin A, inducing CRS-like features as a function of vitamin A toxicity, but without the associated dysmorphogenesis. A number of environmental factors are discussed that may plausibly be candidates for this role, and suggestions are offered for testing the model. The model also suggests a number of measures that may be effective both in reducing the risk of fetal CRS in women who acquire rubella in their first trimester and in reversing or minimizing regressive autism among children in whom the diagnosis is suspected or confirmed.

Does India Need a Universal High-Dose Vitamin A Supplementation Program?

High dose vitamin A (HDVA) concentrate began to be distributed in India in 1970 as a short-term, stop-gap approach to reduce clinical signs of vitamin A deficiency. As this problem declined globally, the purpose of distributing them changed to the reduction of young child mortality. However, their impact on this has also declined, if not disappeared, as suggested in India by the enormous DEVTA study. This may be because of improved protection against and treatment of the main morbidity involved, measles and diarrhea. At the same time, semi-annual provision of mega-doses of vitamin A is not without risks, in particular linked to children's vaccination status. While a single dose is inexpensive, large-scale implementation of HDVA programs is expensive, particularly the opportunity cost involved in reducing the time health workers involved have to deal with their other commitments. Balancing potential benefits, risks and costs leads us to recommend an immediate cessation of the distribution of HDVA in India.

Within-individual differences in plasma ferritin, retinol-binding protein, and zinc concentrations in relation to inflammation observed during a short-term longitudinal study are similar to between-individual differences observed cross-sectionally

BACKGROUND

Cross-sectional (CS) surveys indicate that individuals with acute inflammation have higher plasma ferritin (pF), and lower retinol-binding protein (RBP) and zinc (pZn) concentrations than those without. In populations with a high burden of infection, correction factors (CFs) or regression corrections (RCs) are applied to biomarkers to estimate the prevalence of micronutrient (MN) deficiencies adjusted for inflammation. This assumes that individuals with and without inflammation have the same nutritional status, which may not be the case.

OBJECTIVES

The aim of this study was to investigate relations between short-term, longitudinal within-individual changes in acute phase proteins (C-reactive protein [CRP], α-1-acid glycoprotein [AGP]) and biomarkers of MN status (pF, soluble transferrin receptor [sTfR], RBP, and pZn), and compare them to CS differences.

METHODS

Two blood samples were obtained 21 d apart from 451 asymptomatic Burkinabé children aged 6-23 mo. To calculate CFs, inflammation was defined as CRP >5 mg/L or AGP >1 g/L, or both. The RC approach adjusted MN biomarkers to a presumably healthy reference point within the study population (10th percentile CRP or AGP concentration). CS CFs and RCs were estimated from a naive regression model, treating observations from the same children as independent. Longitudinal CFs and RCs, to estimate effects of within-individual changes in CRP and/or AGP, were estimated from general linear models, accounting for repeated measures.

RESULTS

In CS models, geometric mean pF and sTfR concentrations were 8-340% greater, and RBP and pZn 2-18% lower, in children with inflammation than those without. Except for sTfR, biomarker concentrations differed in the same direction and by similar magnitude within individuals whose inflammation status changed during the observation period. Although geometric mean MN concentrations differed significantly when adjusted with CS compared with longitudinal models, the estimated prevalence of MN deficiencies in CS and longitudinally adjusted models was similar.

CONCLUSIONS

The CF and RC approaches to adjust MN biomarkers for inflammation between individuals in CS surveys are valid approaches for data collection and programmatic decisions in comparable populations. This study was registered at clinicaltrials.gov as NCT00944853.

Association of HCV Infection with C-Reactive Protein: National Health and Nutrition Examination Survey (NHANES), 2009⁻2010

The relationship between hepatitis C virus (HCV) infection and C-reactive protein (CRP), which is an inflammatory biomarker, is limited in studies with the general population. It was hypothesized that changes in CRP levels are genotype-dependent in the general population with HCV infection. Thus, this study aimed to assess the prevalence of HCV infection and compare CRP levels with an anti-HCV antibody, HCV-RNA status, and HCV genotypes. A total of 5611 adult participants from the National and Health Nutrition Examination (NHANES), 2009⁻2010 survey were analyzed. Proc survey frequency, means, and multivariate regression were used due to the complex survey design of NHANES. The prevalence of HCV infection among the study population was 1.6%. There were lower mean CRP levels among people with anti-HCV antibody positive status compared to those with antibody negative status (0.12 ± 0.08 vs. 0.24 ± 0.02, p = 0.08, 95% Confidence Intervals, CI: -1.12 to 0.07). Mean CRP levels were also lower in people with HCV-RNA positive status compared to those with HCV-RNA negative status (0.56 ± 0.03 vs. 0.48 ± 0.05, p = 0.62 and 95% CI: -1.37 to 0.86). However, these differences were non-significant. With respect to HCV genotypes, significantly higher CRP levels were noted among people infected with HCV genotype 2 vs. genotype 1 (0.53 ± 0.06 vs. 0.23 ± 0.05, p < 0.01, 95% CI: -0.58 to -0.02) and those with HCV genotype 2 vs. HCV genotype 3 (0.53 ± 0.06, 0.28 ± 0.04, p < 0.01, 95% CI: 0.02 to 0.48). Further studies are needed to confirm this finding.

Plasma Retinol Levels and High-Sensitivity C-Reactive Protein in Prepubertal Children

The relationship between C-reactive protein (CRP) levels and plasma antioxidants has been established in adults. However, the association has been rarely investigated in healthy children. Thus, we examined the cross-sectional association of high-sensitivity CRP (hs-CRP) levels with fat-soluble plasma antioxidant concentrations in a cohort of healthy prepubertal children. We determined hs-CRP levels in 543 healthy six⁻eight-year-old children using a high-sensitivity CRP enzyme-linked immuno sorbent assay (ELISA) kit. The plasma concentrations of lipids, apolipoproteins and lipid-soluble antioxidants (α-tocopherol, γ-tocopherol, lycopene, α-carotene, β-carotene and retinol) were determined using standardized methods. Pearson correlation analysis showed significant correlations between plasma hs-CRP and α-carotene and retinol concentrations. After adjusting by sex, body mass index (BMI) and lipid levels, only the association with retinol remains significant, with children in the highest hs-CRP tertile group (hs-CRP ≥ 0.60 mg/dL) showing significantly lower levels of retinol than those from the tertiles 1 and 2. A stepwise linear regression selected retinol, BMI, apo A-I and sex as predictors of hs-CRP levels, in a model explaining 19.2% of the variability of hs-CRP. In conclusion, in healthy prepubertal children, after adjusting by sex, BMI and lipid levels, hs-CRP concentrations were highly associated with plasma retinol, which is transported in blood bound to retinol-binding protein but were not associated with the lipoprotein-bound antioxidants.

Low plasma vitamin A concentration is associated with tuberculosis in Moroccan population: a preliminary case control study

BACKGROUND

Vitamin A plays numerous roles in immune system. Its deficiency alters both the innate and adaptive immunity. Previous results reported that the micronutrients deficiency, particularly vitamin A, is observed in patients with tuberculosis. Thus, we aimed in this study to assess vitamin A concentrations in Moroccan patients with tuberculosis to set up a large efficacy study of vitamin A supplementation for TB infected patients. Plasma retinol concentration was measured by HPLC in 44 recently diagnosed TB patients and 40 healthy controls.

RESULTS

We showed that plasma vitamin A is significantly lower in tuberculosis patients as compared to healthy controls (p < 0.0001). Moreover, no significant association was found between vitamin A deficiency and, TB severity and patients' ages.

CONCLUSION

Our study confirms the association between low vitamin A levels and tuberculosis disease.

Current Capabilities and Limitations of Stable Isotope Techniques and Applied Mathematical Equations in Determining Whole-Body Vitamin A Status

BACKGROUND

Retinol isotope dilution (RID) methodology provides a quantitative estimate of total body vitamin A (VA) stores and is the best method currently available for assessing VA status in adults and children. The methodology has also been used to test the efficacy of VA interventions in a number of low-income countries. Infections, micronutrient deficiencies (eg, iron and zinc), liver disease, physiological age, pregnancy, and lactation are known or hypothesized to influence the accuracy of estimating total body VA stores using the isotope dilution technique.

OBJECTIVE

Our objectives were to review the strengths and limitations of RID methods, to discuss what is known about the impact of various factors on results, and to summarize contributions of model-based compartmental analysis to assessing VA status.

METHODS

Relevant published literature is reviewed and discussed.

RESULTS

Various equations and compartmental modeling have been used to estimate the total body VA stores using stable isotopes, including a newer 3-day equation that provides an estimate of total body VA stores in healthy adults. At present, there is insufficient information on absorption of the isotope tracer, and there is a need to further investigate how various factors impact the application of RID techniques in field studies.

CONCLUSIONS

Isotope dilution methodology can provide useful estimates of total body VA stores in apparently healthy populations under controlled study conditions. However, more research is needed to determine whether the method is suitable for use in settings where there is a high prevalence of infection, iron deficiency, and/or liver disease.

Serum retinol concentrations demonstrate high specificity after correcting for inflammation but questionable sensitivity compared with liver stores calculated from isotope dilution in determining vitamin A deficiency in Thai and Zambian children

BACKGROUND

The WHO estimates that 190 million preschool children have vitamin A deficiency (VAD). Serum retinol (SR) concentration is a common indicator of vitamin A (VA) status, but SR is homeostatically controlled and suppressed during inflammation, which may lead to misdiagnosis.

OBJECTIVE

The sensitivity and specificity of SR compared with VA total liver reserves (TLRs) were evaluated for VAD in children from Thailand (n = 37) and Zambia (n = 128). SR was adjusted for inflammation in the Zambian children.

DESIGN

Each child was classified as VA-deficient or not based on cutoffs of <0.1 μmol VA/g liver with the use of retinol isotope dilution and <0.7 μmol/L for SR concentrations. Four categories of infection status in the Zambian children were based on elevated C-reactive protein (CRP) and α1-acid glycoprotein (AGP). Sensitivity and specificity were calculated with the use of unadjusted and inflammation marker-adjusted SR cutoffs.

RESULTS

VAD was 65% and 0% according to TLRs and SR, respectively, in Thai children and 0% and 17%, respectively, in Zambian children. No true positive VAD cases occurred; thus, sensitivity was 0% and indeterminable, respectively; specificity was 100% and 82.8%, respectively. CRP was elevated in 26.6% of Zambian children, whereas 97.7% had elevated AGP, categorizing them as having no infection (2.3%) or in early (26.6%) or late (58.6%) convalescence. With the use of marker-adjusted SR cutoffs of 0.6 μmol/L for late convalescence and 0.5 μmol/L for early convalescence, the adjusted prevalence of SR deficiency was 2.3%, increasing specificity to 97.3%.

CONCLUSIONS

No cases of VAD were identified by both TLRs and SR (true positives) in Thai or Zambian children. Specificity of SR to evaluate VAD was high, but additional research is needed to investigate sensitivity. Adjusting SR cutoffs for inflammation improved specificity by reducing false positives. SR as a VAD indicator may depend on infection rates, which should be taken into consideration. These studies were registered at clinicaltrials.gov as NCT01061307 (for Thailand) and NCT01814891 (for Zambia).

Bioavailability of iron, vitamin A, zinc, and folic acid when added to condiments and seasonings

Seasonings and condiments can be candidate vehicles for micronutrient fortification if consumed consistently and if dietary practices ensure bioavailability of the nutrient. In this review, we identify factors that may affect the bioavailability of iron, vitamin A, zinc, and folic acid when added to seasonings and condiments and evaluate their effects on micronutrient status. We take into consideration the chemical and physical properties of different forms of the micronutrients, the influence of the physical and chemical properties of foods and meals to which fortified seasonings and condiments are typically added, and interactions between micronutrients and the physiological and nutritional status of the target population. Bioavailable fortificants of iron have been developed for use in dry or fluid vehicles. For example, sodium iron ethylenediaminetetraacetic acid (NaFeEDTA) and ferrous sulfate with citric acid are options for iron fortification of fish and soy sauce. Furthermore, NaFeEDTA, microencapsulated ferrous fumarate, and micronized elemental iron are potential fortificants in curry powder and salt. Dry forms of retinyl acetate or palmitate are bioavailable fortificants of vitamin A in dry candidate vehicles, but there are no published studies of these fortificants in fluid vehicles. Studies of zinc and folic acid bioavailability in seasonings and condiments are also lacking.

Undernutrition, the acute phase response to infection, and its effects on micronutrient status indicators

Infection and undernutrition are prevalent in developing countries and demonstrate a synergistic relation. Undernutrition increases infection-related morbidity and mortality. The acute phase response (APR) is an innate, systemic inflammatory reaction to a wide array of disruptions in a host's homeostasis, including infection. Released from immune cells in response to deleterious stimuli, proinflammatory cytokines act on distant tissues to induce behavioral (e.g., anorexia, weakness, and fatigue) and systemic effects of the APR. Cytokines act to increase energy and protein requirements to manifest fever and support hepatic acute phase protein (APP) production. Blood concentrations of glucose and lipid are augmented to provide energy to immune cells in response to cytokines. Additionally, infection decreases intestinal absorption of nutrients and can cause direct loss of micronutrients. Traditional indicators of iron, zinc, and vitamin A status are altered during the APR, leading to inaccurate estimations of deficiency in populations with a high or unknown prevalence of infection. Blood concentrations of APPs can be measured in nutrition interventions to assess the time stage and severity of infection and correct for the APR; however, standardized cutoffs for nutrition applications are needed. Protein-energy malnutrition leads to increased gut permeability to pathogens, abnormal immune cell populations, and impaired APP response. Micronutrient deficiencies cause specific immune impairments that affect both innate and adaptive responses. This review describes the antagonistic interaction between the APR and nutritional status and emphasizes the need for integrated interventions to address undernutrition and to reduce disease burden in developing countries.

The acute phase response affected traditional measures of micronutrient status in rural Zambian children during a randomized, controlled feeding trial

The acute phase response (APR) to infection can alter blood-based indicators of micronutrient status. Data from a 3-mo randomized, controlled feeding trial in rural Zambian children (n = 181, aged 3-5 y) were used to determine the impact of the APR on indicators of vitamin A and iron status using baseline and final blood samples. Concentrations of acute phase proteins were categorized as raised C-reactive protein (CRP; >5 and >10 mg/L) only, both raised CRP and α1-acid glycoprotein (AGP; >1.2 g/L), raised AGP only, and neither CRP nor AGP raised to identify the respective stages of infection: incubation, early convalescence, convalescence, and healthy state. Data were insufficient to examine the incubation stage of infection. A CRP concentration of >5 mg/L was an effective elevation cutoff point in this population to show impact on micronutrient markers. Time did not affect hemoglobin, serum ferritin, or serum retinol concentrations (P > 0.05). During early convalescence, hemoglobin decreased (14-16%; P ≤ 0.05), serum ferritin increased (279-356%; P ≤ 0.05), and serum retinol decreased (20-30%; P ≤ 0.05). Serum retinol concentrations did not change during convalescence; however, hemoglobin remained depressed (4-9%) and serum ferritin was elevated (67-132%) (both P ≤ 0.05). Modified relative dose response values were unaffected by the APR (P > 0.05) but increased between time points (16%; P ≤ 0.05), indicating a decrease in liver vitamin A reserves on the background of a semiannual vitamin A supplementation program. The observed prevalence of anemia and vitamin A deficiency assessed by serum retinol concentration was higher during the APR (P ≤ 0.05). It is important to consider the impact of infection on dietary interventions and to adjust for acute phase proteins when assessing iron status or vitamin A status by serum retinol concentration alone in children.

Review of the safety and efficacy of vitamin A supplementation in the treatment of children with severe acute malnutrition

Background

World Health Organization (WHO) guidelines recommend for children with severe acute malnutrition (SAM), high-dose vitamin A (VA) supplements be given on day 1 of admission, and on days 2 and 14 in the case of clinical signs of vitamin A deficiency (VAD). Daily low-dose VA follows, delivered in a premix added to F-75 and F-100. This study aimed to systematically review the evidence for safety and effectiveness of high-dose VA supplementation (VAS) in treatment of children with SAM.

Methods

A comprehensive literature review was undertaken for all relevant randomized controlled trials (RCT) and observational studies from 1950 to 2012. Studies identified for full review were evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology using a set of pre-defined criteria: indirectness; inconsistency; imprecision; and study limitations. A quality rating of high, moderate, or low was then assigned to each study, and only those attaining moderate to high were considered in making recommendations.

Results

Of the 2072 abstracts screened, 38 met criteria for full review, and 20 were rated moderate to high quality. Only one study replicated the WHO VA protocol in children with SAM. Indirectness was a critical limitation, as studies were not exclusive to children with SAM. There was inconsistency across trials for definitions of malnutrition, morbidities, and ages studied; and imprecision arising from sub-group analyses and small sample sizes. Evidence showed improved outcomes associated with low-dose compared to high-dose VAS, except in cases presenting with signs of VAD, measles, and severe diarrhea or shigellosis. Adverse outcomes related to respiratory infection, diarrhea, and growth were associated with high-dose VAS in children who were predominantly adequately nourished. No adverse effects of the high dose were found in children with SAM in the trial that replicated the WHO VA guideline.

Conclusion

This is the first systematic review of the safety and efficacy of high-dose VAS in treatment of SAM. We recommend a low-dose VAS regimen for children with SAM, except in cases presenting with measles, severe diarrhea (shigellosis), and any indication of VAD. Further research is needed in exclusively malnourished children and to explore alternate delivery strategies.

Retinoids, race and the pathogenesis of dengue hemorrhagic fever

Dengue hemorrhagic fever (DHF) is the most significant mosquito-borne viral disease worldwide in terms of illness, mortality and economic cost, but the pathogenesis of DHF is not well understood and there is no specific treatment or vaccine. Based on evidence of liver involvement, it is proposed that dengue virus and retinoids interact to cause cholestatic liver damage, resulting in the spillage of stored retinoids into the circulation and in an endogenous form of hypervitaminosisis A manifested by the signs and symptoms of the disease, including: fever, severe joint and bone pain, capillary leakage, thrombocytopenia, headache, and gastrointestinal symptoms. While retinoids in low concentration are essential for numerous biological functions, they are prooxidant, cytotoxic, mutagenic and teratogenic in higher concentration, especially when unbound to protein, and an endogenous form of vitamin A intoxication is recognized in cholestasis. The model tentatively explains the observations that 1) repeat infections are more severe than initial dengue virus infections; 2) the incidence of denue has increased dramatically worldwide in recent decades; 3) DHF is less prevalent in people of African ancestry than those of other racial backgrounds; and 4) infants are protected from dengue. The retinoid toxicity hypothesis of DHF predicts the co-existence of low serum concentrations of retinol coupled with high concentrations of retinoic acid and an increased percentage of retinyl esters to total vitamin A. Subject to such tests, it may be possible to treat DHF effectively using drugs that target the metabolism and expression of retinoids.

Role of Fat-Soluble Vitamins A and D in the Pathogenesis of Influenza: A New Perspective

Reduced exposure to solar radiation, leading to a deficiency of vitamin D and hence impaired innate immunity, has been suggested as a trigger for influenza viral replication and as an explanation of seasonal influenza. Although this hypothesis accounts for many unexplained facts about the epidemiology of influenza, gaps remain in understanding the pathogenesis and manifestations of the disease. Several observations suggest a role for vitamin A compounds (retinoids) in the disease. This paper presents a new model of the etiopathogenesis of influenza, suggesting that host resistance and susceptibility depend importantly on the ratio of vitamin D to vitamin A activity. Retinoid concentrations within normal physiological limits appear to inhibit influenza pathogenesis whereas higher background concentrations (i.e., very low vitamin D : A ratios) increase the risk of severe complications of the disease. There is also evidence that influenza-induced or preexisting liver disease, diabetes, and obesity worsen the severity of infection, possibly via liver dysfunction and alterations in retinoid metabolism. The model could be tested by determining the presence of retinoids in the secretions of patients with influenza and by studies of retinoid profiles in patients and controls. Potential strategies for prevention and treatment are discussed.

Relationships between serum concentrations of C-reactive protein and micronutrients, in patients with tuberculosis

Studies on the serum concentrations of micronutrients in tuberculosis (TB), and their relationship to the acute-phase response (APR), are scarce. The serum concentrations of zinc, copper, selenium and vitamins A and E in 46 smear-positive cases of pulmonary TB (PTB) from Ecuador were therefore compared with those in 10 healthy Ecuadorian volunteers, and the correlations between these concentrations and the serum concentration of C-reactive protein (CRP) were evaluated. Compared with the healthy volunteers, the PTB cases had significantly lower serum concentrations of zinc, retinol and selenium and significantly higher serum concentrations of copper. Both groups had moderately high concentrations of selenium in their sera. The PTB cases who had >50 mg CRP/ litre (a concentration indicative of an APR) had lower serum concentrations of retinol and zinc than the cases with lower CRP concentrations. In patients with PTB, hypozincaemia and hyporetinolaemia are strongly associated with the APR. It is therefore necessary to consider the extent of activation of the APR when interpreting serum micronutrient concentrations in patients with TB.

The importance of controlling for the acute-phase response in the population-based assessment of vitamin A status: a study in children of pre-school age in Uganda

OBJECTIVE

To improve estimates of vitamin A deficiency in children of pre-school age in the 2006 Uganda Demographic and Health Survey (UDHS 2006).

DESIGN

A cross-sectional study in which dried blood spot samples were analysed for C-reactive protein (CRP). Retinol-binding protein (RBP) had previously been analysed using a commercial enzyme immunoassay.

SETTING

A population-based study in Uganda.

SUBJECTS

A systematically selected subset of the dried blood spot samples collected from children aged 6–59 months for UDHS 2006. Children were categorized into ‘normal CRP’ (Group A) and ‘raised CRP’ (Group B) using a CRP cut-off of 5mg/l. A correction factor was calculated to adjust the Group B RBP values for the influence of the acute-phase response.

RESULTS

Geometric mean CRP was 6.2 (95% CI 5.5, 7.0) mg/l, 1.6 (95% CI 1.5, 1.8) mg/l and 17.9 (95% CI 16.4, 19.6) mg/l in all children, in Group A and in Group B, respectively. Geometric mean RBP in all children, in Group A and in Group B was 1.18 (95% CI 1.14, 1.22)mmol/l, 1.26 (95% CI 1.20, 1.33)mmol/l and 1.12 (95% CI 1.07, 1.17)mmol/l, respectively, before correction. Correction increased mean RBP in Group B to 1.26 (95% CI 1.21, 1.31)mmol/l. The prevalence of vitamin A deficiency (RBP,0.825mmol/l) reduced from 18.4% (95% CI 17.2, 23.0%) to 13.9% (95% CI 11.3, 16.5%).

CONCLUSIONS

Correcting for the acute-phase response significantly reduced the prevalence of vitamin A deficiency; thus, the acute-phase response should be considered when vitamin A status is assessed using RBP in order to improve population-level estimates of vitamin A deficiency.

Efficacy of a high-dose in addition to daily low-dose vitamin A in children suffering from severe acute malnutrition with other illnesses

Background

Efficacy of high-dose vitamin A (VA) in children suffering from severe acute malnutrition (SAM) has recently been questioned. This study compared the efficacy of a single high-dose (200,000 IU) in addition to daily low-dose (5000 IU) VA in the management of children suffering from SAM with diarrhea and/or acute lower respiratory tract infection (ALRI).

Methods

In a randomized, double-blind, controlled clinical trial in icddr,b, Bangladesh during 2005–07, children aged 6–59 months with weight-for-height <−3 Z-score and/or bipedal edema (SAM) received either a high-dose VA or placebo on admission day. Both the groups received 5,000 IU/day VA in a multivitamins drop for 15 days and other standard treatment which is similar to WHO guidelines.

Results

A total 260 children (130 in each group) were enrolled. All had diarrhea, 54% had concomitant ALRI, 50% had edema, 48.5% were girl with a mean±SD age of 16±10 months. None had clinical signs of VA deficiency. Mean±SD baseline serum retinol was 13.15±9.28 µg/dl, retinol binding protein was 1.27±0.95 mg/dl, and pre-albumin was 7.97±3.96 mg/dl. Median (inter quartile range) of C-reactive protein was 7.8 (2.1, 22.2) mg/L. Children of the two groups did not differ in any baseline characteristic. Over the 15 days treatment period resolution of diarrhea, ALRI, edema, anthropometric changes, and biochemical indicators of VA were similar between the groups. The high-dose VA supplementation in children with SAM did not show any adverse event.

Conclusions

Efficacy of daily low-dose VA compared to an additional single high-dose was not observed to be better in the management of children suffering from SAM with other acute illnesses. A single high-dose VA may be given especially where the children with SAM may leave the hospital/treatment center early.

Trial Registration

ClinicalTrials.gov NCT00388921

In vitro antibacterial and time-kill assessment of crude methanolic stem bark extract of Acacia mearnsii de wild against bacteria in shigellosis

Shigellosis is an important cause of worldwide morbidity and mortality among young children and old people for which treatment with antimicrobial agents is limited. Hence, the need for curative potentials obtainable from medicinal plants becomes inevitable. This study was carried out to assess the antibacterial potentials of crude methanolic extract of the stem bark of Acacia mearnsii against some selected bacteria of clinical importance in shigellosis. The bacteria were inhibited by the extract to produce concentration dependent inhibition zones. The extract exhibited a varied degree of antibacterial activity against all the tested isolates. The MIC values for Gram negative (0.0391–0.3125) mg/mL and those of Gram positive bacteria (0.0781–0.625) mg/mL indicated that the Gram negative bacteria were more inhibited by the extract than the Gram positive bacteria. Average log reduction in viable cell count in time-kill assay ranged between −2.456 Log₁₀ to 2.230 Log₁₀ cfu/mL after 4 h of interaction, and between −2.921 Log₁₀ and 1.447 Log₁₀ cfu/mL after 8 h interaction in 1× MIC and 2× MIC of the extract. The study provided scientific justification for the use of the crude methanolic extract from the stem bark of A. mearnsii in shigellosis. The degree of the antibacterial activity indicated that the crude extract is a potential source of bioactive compounds that could be useful for the development of new antimicrobial agents capable of decreasing the burden of drug resistance and cost of management of diseases of clinical and public health importance in South Africa.

Influence of vitamin A status on the antiviral immunity of children with hand, foot and mouth disease

BACKGROUND & AIMS

Vitamin A (VA) deficiency has been shown to affect antiviral immunity and thus may be related to the progress and outcome of hand, foot and mouth disease (HFMD) in young children. Our objective was to determine whether children with HFMD associated with VA insufficiency displayed a decline in antiviral immunity.

METHODS

450 children with HFMD and 113 non-infected children were included in this study. Dietary investigations were performed using a 24-h dietary questionnaire. The serum concentrations of VA were measured by high-performance liquid chromatography. The serum levels of interferon-α (IFN-α) and enterovirus 71 (EV71) IgM antibodies were detected using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean serum VA concentration for all patients was 0.73 ± 0.26 μmol/L, and 237 (52.7%) of them presented low concentrations (≤ 0.7 μmol/L). Both serum concentrations of VA and IFN-α in the patients with complications were significantly lower than in patients without complications (P < 0.01). The decreased concentrations of IFN-α and EV71-IgM were positively related to lower VA levels (correlation coefficient = 0.58 and 0.41, respectively, P < 0.001).

CONCLUSIONS

Most of the children with HFMD presented VA insufficiency, which was associated with their reduced immunity and more severe illness.

Decrease in shigellosis-related deaths without Shigella spp.-specific interventions, Asia

Despite a high number of cases, deaths have decreased 98% since the 1980s.

In 1999, a review of the literature for 1966–1997 suggested that ≈1.1 million persons die annually of shigellosis, including ≈880,000 in Asia. Our recent review of the literature for 1990–2009 indicates that ≈125 million shigellosis cases occur annually in Asia, of which ≈14,000 are fatal. This estimate for illnesses is similar to the earlier estimate, but the number of deaths is 98% lower; that is, the lower estimate of deaths is associated with markedly reduced case-fatality rates rather than fewer cases. Shigella spp.–related deaths decreased substantially during a period without Shigella spp.–specific interventions. We speculate that nonspecific interventions, e.g., measles vaccination, vitamin A supplementation, and improved nutrition, may have led to the reduced number of shigellosis-related deaths.

Characteristics of children with Shigella encephalopathy: experience from a large urban diarrhea treatment center in Bangladesh

BACKGROUND

Encephalopathy is a serious neurologic complication from shigellosis often with fatal outcome but data on simple clinical and sociodemographic predicting factors are limited. We sought to identify those factors in children.

METHODS

In this unmatched case-control design, children of both sexes, aged 0 to 15 years having positive stool culture for Shigella from 1997 to 2006 were studied. Children with Shigella encephalopathy constituted the cases (n = 29), whereas randomly selected children with shigellosis having no encephalopathy constituted controls (n = 87).

RESULTS

The case-fatality was significantly higher among the cases than among controls (7% vs. 0%, RR: 4.2, CI: 3.0-5.9, P = 0.013). In logistic regression analysis, children with Shigella encephalopathy more often had an illiterate father (OR: 5.4, 95% CI: 1.1-27.1, P = 0.038), stopped breast-feeding in the neonatal period (OR: 41.3, 95% CI: 4.2-403.1, P = 0.001), had dehydrating diarrhea (OR: 9.9, 95% CI: 2.1-45.9, P = 0.004) with a duration of <1 day (OR: 29.4, 95% CI: 2.1-43.2, P = 0.004), and were more likely to be severely stunted (OR: 6.4, 95% CI: 1.2-34.9, P = 0.033).

CONCLUSION

Education of parents about the value of exclusive breast-feeding and of prompt hydration in children with Shigella is critical to minimize morbidity and deaths.

Influência da resposta inflamatória de fase aguda nos níveis séricos de retinol e da proteína de ligação do retinol em pacientes com AIDS

INTRODUÇÃO: a hiporretinolemia constitui fator prognóstico independente em pacientes com AIDS, e a atividade inflamatória causa redução dos níveis séricos deste nutriente na população em geral. Entretanto, faltam estudos que avaliem o impacto da atividade inflamatória sobre o nível sérico do retinol em pacientes com AIDS. MÉTODOS: foram avaliados transversalmente 41 pacientes internados por complicações da AIDS, que tiveram quantificados alguns marcadores de inflamação (proteína C reativa e fator de necrose tumoral alfa) e concentrações séricas de retinol e da proteína de ligação do retinol. RESULTADOS: apesar da baixa (14,6%) prevalência de hiporretinolemia evidenciou-se correlação negativa dos marcadores de inflamação com os níveis séricos de retinol e de sua proteína de ligação nos pacientes com AIDS. CONCLUSÕES: a atividade inflamatória de fase aguda está associada a baixos níveis séricos de retinol em indivíduos com AIDS.

Impact of micronutrient deficiencies on obesity

Micronutrient deficiencies have been found in obese individuals across age groups worldwide. While the effects of micronutrient deficiencies on human functions have been studied widely in different populations, there is limited information on how these micronutrient deficiencies affect obese populations. An examination of the available literature suggests associations exist between micronutrient deficiencies and obesity in different populations. These associations and possible mechanisms of the deficiencies' metabolic effects, such as their influence on leptin and insulin metabolism, are discussed here. Further studies are needed to clarify the roles of the different micronutrient deficiencies with respect to obesity and its comorbid conditions.

Malaria and vitamin A deficiency in African children: a vicious circle?

Vitamin A deficiency and malaria are both highly prevalent health problems in Africa. Vitamin A deficiency affects over 30 million children, most of whom are in the age-group (under five years) most affected by malaria. Vitamin A deficiency increases all-cause mortality in this part of the population, and malaria is an important cause of death in children at this age. A low serum retinol concentration (a marker of vitamin A deficiency) is commonly found in children suffering from malaria, but it is not certain whether this represents pre-existing vitamin A deficiency, a contribution of malaria to vitamin A deficiency, or merely an acute effect of malaria on retinol metabolism or binding. In this paper, available evidence in support of a causal relationship in each direction between vitamin A deficiency and malaria is reviewed. If such a relationship exists, and especially if this is bidirectional, interventions against either disease may convey an amplified benefit for health.

Micronutrient concentrations in respiratory syncytial virus and human metapneumovirus in Yemeni children

BACKGROUND

Acute respiratory infections (ARI) cause significant childhood mortality. Nutritional homeostasis, particularly micronutrient levels, is important in modulating response to infection. More information is required regarding micronutrient levels in ARI viral infections, especially newly identified viruses such as human metapneumovirus (HMPV).

AIM

To describe zinc, copper, selenium and vitamins A and E concentrations in children with respiratory syncytial virus (RSV) and/or HMPV in relation to levels of C-reactive protein (CRP).

METHODS

The presence of RSV/HMPV in nasopharyngeal aspirates (NPA) was identified in 246 children using RTPCR. Zinc, copper, selenium and vitamins A and E concentrations were measured using inductive coupled plasma mass spectrometry and high performance liquid chromatography.

RESULTS

183 children had RSV, 39 had HMPV and 24 were co-infected. Zinc concentrations were lower in children with HMPV than in children with RSV or RSV/HMPV co-infection. Copper concentrations were lower in children with RSV than in children with RSV/HMPV or HMPV and zinc/copper ratios were lower in children with HMPV/RSV or RSV than in children with HMPV alone. Retinol and a alpha-tocopherol were lower in children with RSV than in children with HMPV. Most children had low selenium concentrations. Children with RSV and raised CRP (>5 mg/L) had higher copper and lower zinc/copper ratios than those with low CRP (< or =5 mg/L). Children with HMPV and raised CRP had higher copper and lower zinc concentrations than children with low CRP. Children with RSV/HMPV and raised CRP had higher copper concentrations. Children with RSV/HMPV and raised CRP had higher a alpha-tocopherol concentrations.

CONCLUSION

The profiles of micronutrients differ in children with RSV and HMPV and are confounded by CRP. These results may guide strategies for micronutrient supplementation in ARI.

Bone pain, growth failure, and skin rash after an upper respiratory illness in a boy with autism: possible association with altered retinoid metabolism

Symptoms of bone pain and skin rashes are not uncommon following a variety of infectious illnesses, but the underlying mechanisms are not well understood. The case of a 9-year-old boy with autism was recently described, who was hospitalized because of pain in the right hip, refusal to walk, fatigue, irritability, skin rash, and subsequent gingival swelling after an unspecified upper respiratory illness. The boy was diagnosed with scurvy. However, the gingival symptoms occurred after treatment with indomethacin, which lowers vitamin C levels; severe bone pain and fatigue are also well-documented symptoms of hypervitaminosis A. This review of a case report of a boy with autism provides an opportunity to present a new hypothesis of the mechanism of these postinfection symptoms in the context of an increasingly common condition of childhood.

Serum retinol concentrations in hospitalized severe protein-energy malnourished children

BACKGROUND

Vitamin A deficiency (VAD) is a major nutritional problem in many developing countries. Vitamin A status has been reported to be adversely affected in protein-energy malnutrition (PEM).

OBJECTIVE

To assess and compare serum retinol concentrations in hospitalized children with severe PEM and normal ones.

METHODS

A prospective series of 34 malnourished and 29 normal control children, <60 months old, hospitalized at IMIP, Recife-PE were recruited for the study between August 2004 and May 2005. Serum retinol level was assayed by high performance liquid chromatography and concentrations adjusted for presence of inflammation as evidenced by levels of C-reactive protein. Blood retinol level was compared according to nutritional status (severe PEM versus normal), gender, age, maternal schooling, family income, breastfeeding practice, residence and perceived morbidity.

RESULTS

The prevalence of low serum retinol (<0.70 micromol l(-1)) was 41.2% in children with severe PEM and 24.1% in normal children. Serum retinol concentrations were lower in children whose mothers had low schooling (p = 0.025) and families with low per capita income (p = 0.049), regardless of their nutritional status. Serum retinol concentrations had similar distribution between children with severe PEM and normal, when adjusted for gender (p > 0.05), age (p > 0.05), maternal schooling (p > 0.05), family income (p > 0.05), breastfeeding practice (p > 0.05) and residence (p > 0.05). However, malnourished children with diarrhoea showed lower serum retinol concentrations (p = 0.021) compared to those without diarrhoea.

CONCLUSION

VAD was prevalent in hospitalized children with severe PEM and also among normal ones although in lesser magnitude. Intervention for prevention and control of deficiency of vitamin A are recommended in settings where diarrhea is endemic and there are unfavorable socio-economical conditions.

Using plasma acute-phase protein concentrations to interpret nutritional biomarkers in apparently healthy HIV-1-seropositive Kenyan adults

Inflammation influences the assessment of nutritional status. For example, inflammation reduces plasma retinol concentrations and vitamin A deficiency is overestimated. Conversely inflammation increases plasma ferritin concentrations and Fe deficiency is underestimated. Blood samples were obtained from 163 free-living HIV-1-infected adults, not on continuous medication, anti-retroviral drugs or micronutrients, not unwell and who had not reached WHO stage IV of HIV/AIDS. We used four markers of inflammation, C-reactive protein (CRP), α1-acid glycoprotein (AGP), α1-antichymotrypsin and erythrocyte sedimentation rate but mainly CRP and AGP were used to separate the subjects into four groups: ‘healthy’ where both CRP and AGP were normal; ‘incubation phase’ where CRP was elevated; ‘early convalescence’ where AGP and CRP were elevated and ‘late convalescence’ where only AGP was elevated. Correction factors were calculated to remove the influence of inflammation from each biomarker and group where inflammation was present and the data are shown before and after recalculation. The correction increased median plasma retinol concentrations of the whole group from 1·16 to 1·33 μmol/l, comparable with values (mean 1·29 μmol/l) in HIV-negative Kenyan women. Median ferritin concentrations fell by about 50 % in both sexes and the number of women with plasma ferritin concentrations ≤ 12 μg/l increased from eleven to twenty. The correction also increased plasma carotenoids and Hb but not α-tocopherol concentrations. We suggest that the method described to remove the influence of inflammation from nutritional biomarkers should be generally applicable in apparently healthy people and prevents discarding valuable data because of mild inflammation. The method does now need to be tested in other populations.

Effect of consumption of the nutrient-dense, freshwater small fishAmblypharyngodon molaon biochemical indicators of vitamin A status in Bangladeshi children: a randomised, controlled study of efficacy

In Bangladesh, some commonly consumed, indigenous, freshwater small fish species (eaten whole with bone, head and eyes) such as mola (Amblypharyngodon mola) are nutrient-dense, containing preformed vitamin A as retinol and especially 3,4-dehydroretinol. The objective of the present randomised, controlled efficacy study was to evaluate the effects of mola on biochemical indicators of vitamin A status. Children (n196), aged 3–7 years, with serum retinol 0·36–0·75 μmol/l, were randomly allocated to one of three treatment groups to receive a daily test meal (6 d/week for 9 weeks) of rice and vegetable curry (no vitamin A)ad libitumand 50 g fish curry consisting of: (1) mola, 600 retinol activity equivalents (RAE) (using 40 % biological activity of 3,4-dehydroretinol isomers) (experimental group,n66); (2) rui (Labeo rohita), a large fish (no vitamin A), with added retinyl palmitate, 600 RAE (positive control group,n65); or (3) rui, 0 RAE (negative control group,n65). The nutrient compositions of the dishes were analysed. After 9 weeks, no significant treatment effects were observed for serum retinol (P = 0·52) and retinol-binding protein (P = 0·81) in the experimental group compared with the negative control, whereas the positive control improved significantly (P < 0·001). The present results do not suggest conversion of the large amount of 3,4-dehydroretinol in mola curry to retinol. Further research on the functional effect of mola in humans is needed. Mola is a nutrient-dense animal-source food, rich in haem Fe, Zn and especially Ca, thus consumption of mola in Bangladesh should continue to be encouraged.

Role of retinol in protecting epithelial cell damage induced by Clostridium difficile toxin A

Vitamin A (retinol), a fat-soluble vitamin, is an essential nutrient for the normal functioning of the visual system, epithelial cell integrity and growth, immunity, and reproduction. Our group has investigated the effect of high doses of oral vitamin A on early childhood diarrhea in our prospective community-based studies from Northeast Brazil and found a beneficial role in reducing the mean duration but not incidence of diarrheal episodes. In this study, we explored the role of retinol supplementation in intestinal cell lines following Clostridium difficile toxin A (TxA) challenge. C. difficile is the most common anaerobic pathogen borne with antibiotic-borne diarrhea and pseudomembranous colitis. Since retinol is critical for the integrity of tight junctions and to modulate the cell cycle, we have focused on changes in transepithelial electrical resistance (TEER) in Caco-2, a more differentiated intestinal cell line, and on models of cell proliferation, migration and viability in IEC-6 cells, an undifferentiated crypt cell line, following TxA injury. In this model, retinol therapy reduced apoptosis, improved cell migration and proliferation, and prevented the reduction in TEER, following C. difficile TxA challenge in a glutamine-free medium. These results suggest the role of retinol in protecting intestinal epithelial barrier function from C. difficile TxA enterotoxic damage.

Micronutrients in childhood and the influence of subclinical inflammation

In the present paper biomarkers of micronutrient status in childhood and some of the factors influencing them, mainly dietary intake, requirements and inflammation will be examined. On a body-weight basis the micronutrient requirements of children are mostly higher than those of an adult, but most biomarkers of status are not age-related. A major factor that is often overlooked in assessing status is the influence of subclinical inflammation on micronutrient biomarkers. In younger children particularly the immune system is still developing and there is a higher frequency of sickness than in adults. The inflammatory response rapidly influences the concentration in the blood of several important micronutrients such as vitamin A, Fe and Zn, even in the first 24 h, whereas dietary deficiencies can be envisaged as having a more gradual effect on biomarkers of nutritional status. The rapid response to infection may be for protective reasons, i.e. conservation of reserves, or by placing demands on those reserves to mount an effective immune response. However, because there is a high prevalence of disease in many developing countries, an apparently-healthy child may well be at the incubation stage or convalescing when blood is taken for nutritional assessment and the concentration of certain micronutrient biomarkers will not give a true indication of status. Most biomarkers influenced by inflammation are known, but often they are used because they are convenient or cheap and the influence of subclinical inflammation is either ignored or overlooked. The objective of the present paper is to discuss: (1) some of the important micronutrient deficiencies in childhood influenced by inflammation; (2) ways of correcting the interference from inflammation.

Megalin-mediated reuptake of retinol in the kidneys of mice is essential for vitamin A homeostasis

The reuptake of retinol (ROH) and retinol-binding protein (RBP) in the kidneys is mediated by the endocytic receptor megalin, suggesting an important role for this receptor in vitamin A (VA) metabolism. We examined the extent to which megalin deficiency may affect urinary ROH excretion, levels of ROH and RBP in plasma, as well as storage of VA in liver and kidney. For this purpose, mice with a kidney-specific megalin gene defect (megalin(lox/lox); apoE(Cre)) and control mice (megalin(lox/lox)) were fed either a basal diet containing 4500 retinol equivalents (RE)/kg diet or a diet without VA during experimental periods of 42 and 84 d. Urinary ROH excretion was observed only in megalin(lox/lox); apoE(Cre) mice (P < 0.0001, 2-way ANOVA) and not in the controls. Plasma ROH and RBP differed only by diet (P < 0.05), but not genotype (P = 0.615). A major effect of megalin deficiency, however, was evident in retinyl ester levels in the liver (P < 0.05), which were approximately 37% lower than those in megalin(lox/lox) controls (P < 0.05, Student's t test) during the 84-d period of dietary VA deprivation. Kidney levels of VA were not affected by the receptor gene defect. The findings demonstrate that urinary ROH excretion caused by megalin deficiency requires accelerated mobilization of hepatic VA stores to maintain normal plasma ROH levels, which suggests that megalin plays an essential role in systemic VA homeostasis.

Zinc and vitamin A supplementation in Australian Indigenous children with acute diarrhoea: a randomised controlled trial

OBJECTIVE

To evaluate the role of zinc and vitamin A supplementation in the recovery of Indigenous children hospitalised for acute diarrhoea.

DESIGN

A randomised controlled 2 by 2 factorial trial of supplementation with zinc and vitamin A.

SETTING AND PARTICIPANTS

Aboriginal children (aged < 11 years) hospitalised for acute diarrhoea at Alice Springs Hospital, Northern Territory, April 2001-July 2002.

MAIN OUTCOME MEASURES

Duration of diarrhoeal illness; re-admission for diarrhoeal illness within 120 days.

RESULTS

Our study involved 392 Aboriginal children with 436 episodes of diarrhoea. Supplementation with zinc, vitamin A, or combined zinc and vitamin A had no significant effect on duration of diarrhoea or rate of re-admission compared with placebo. Median diarrhoea duration after starting supplementation was 3.0 days for the vitamin A and zinc supplemented and placebo groups (P values 0.25 and 0.69, respectively). The number of re-admissions did not differ significantly between those receiving vitamin A or zinc and the relevant placebo groups (relative risk [95% CI], 1.2 [0.7-2.1] and 1.3 [0.8-2.1], respectively).

CONCLUSION

Vitamin A and zinc supplementation may not be indicated for in-hospital management of acute diarrhoeal disease in Aboriginal children living in remote areas. This finding may not apply to children with malnutrition, for whom other studies suggest a benefit. Larger trials incorporating more comprehensive data on the vitamin A and zinc status as well as nutritional status of study populations might help to explain the different results in different populations.

All-trans Retinoic Acid Is Increased in the Acute Phase-Related Hyporetinemia During Escherichia coli Mastitis

Blood vitamin A profiles, including concentrations of retinol and its active metabolite retinoic acid, were assessed during the peripartum period and during experimentally induced Escherichia coli mastitis in heifers. Serum retinol decreased in all animals in the immediate postpartum period and normalized within 1 wk after parturition. No significant changes were detectable in the concentrations of retinoic acid isomers during puerperium. Following intramammary E. coli infusion, all cows showed moderate symptoms of systemic disease besides the local signs of inflammation. The presence of a systemic acute-phase reaction was documented by fever, increase in serum amyloid A, and decrease in serum albumin. Retinol concentration in serum also decreased spectacularly during coliform mastitis, and the decline was clearly related to the timing of the acute-phase response. Moreover, a significant increase of all-trans retinoic acid, mirrored by a lowering of 13-cis retinoic acid, was detected during the same time period. The 9-cis isomer of retinoic acid was present in all samples, but it remained below the quantification limit. Results confirmed the decrease in serum retinol during the peripartum period of dairy cows. Furthermore, the study established that profound changes in vitamin A metabolism occur during the acute-phase reaction of coliform mastitis in heifers. The bovine infection model reproduced the acute phase-related hyporetinemia, as previously observed in humans and rats. In addition, all-trans retinoic acid was found to be the most abundant circulating acid isomer during mastitis, providing an indication for a possible key role of all-trans retinoic acid in the modulation of the immune response.

Assessment of vitamin A status with the relative-dose-response test in Peruvian children recovering from pneumonia

BACKGROUND

The relative-dose-response (RDR) test is used to identify subjects with marginal liver vitamin A stores, but its use has not been evaluated during episodes of infection.

OBJECTIVE

The objective was to assess, with the RDR test, the vitamin A status of children recovering from pneumonia.

DESIGN

As part of a double-blind, placebo-controlled clinical trial of high-dose vitamin A supplements among children hospitalized with pneumonia in Lima, Peru, we examined the association of treatment group, nutritional status, severity of disease, and induction of the acute phase response [on the basis of serum C-reactive protein (CRP)] on serum retinol and the RDR test.

RESULTS

Serum retinol was low at admission and increased significantly in both the vitamin A and placebo groups during recovery. Serum CRP had a significant, inverse association with retinol at both admission and discharge. Serum retinol and CRP concentrations never differed significantly between the treatment groups. Among subjects with CRP > or =10 mg/L, 21% in the vitamin A group and 20% in the placebo groups (P = 0.83) had a positive RDR test result. Among subjects with CRP <10 mg/L, 56% in the placebo group but only 6% in the vitamin A group had positive RDR test results (P = 0.002).

CONCLUSION

The RDR test was useful in assessing the vitamin A status of children recovering from pneumonia when CRP concentrations were <10 mg/L but not when CRP concentrations were higher.

The molar ratio of retinol-binding protein to transthyretin in the assessment of vitamin A status in adults. Proposal of a cut-off point

The molar ratio of retinol-binding protein to transthyretin (RBP:TTR) has been proposed as an indirect method to assess vitamin A status in children with inflammation. Neither reference values nor appropriate cut-off point are available for adults. RBP, TTR and retinol were determined in plasma from 100 healthy adults and 31 low-risk surgical patients with no inflammatory response. RBP:TTR percentile distribution from 99 healthy adults with plasma retinol > or = 0.7 micromol/l was: 2.5th = 0.24; 5th = 0.31; 10th = 0.32; 25th = 0.41; 50th = 0.47; 75th = 0.54; 90th = 0.67; 95th = 0.78 and 97.5th = 0.81. In order to define a cut-off point, receiver operating characteristic (ROC) curve was constructed, using plasma retinol as gold standard. ROC curve was based on data from the 131 studied subjects, 11 of whom (8.4%) were classified as deficient on the basis of plasma retinol < 0.7 pmol/l. According to ROC curve criteria, RBP:TTR ratio was considered a good test, the area under the curve being 0.822, p < 0.001. A cut-off-point of < or = 0.37 is proposed to detect vitamin A deficiency in adults, since it allows reaching high sensitivity (81.8%), specificity (79.2%) and predictive value (79.4%). The proposed cut-off point falls between 13th and 14th percentiles.

Estimation of the effect of the acute phase response on indicators of micronutrient status in Indonesian infants

Many indicators of micronutrient status change during infection because of the acute phase response. In this study, relationships between the acute phase response, assessed by measuring concentrations of C-reactive protein (CRP), alpha(1)-antichymotrypsin (ACT) and alpha(1)-acid glycoprotein (AGP), and indicators of micronutrient status were analyzed in 418 infants who completed a 6-mo randomized, double-blind, placebo-controlled, supplementation trial with iron, zinc and/or beta-carotene. The acute phase response, defined by raised CRP (plasma concentration >10 mg/L), raised AGP (>1.2 g/L), or both raised CRP and AGP, significantly affected indicators of iron, vitamin A and zinc status, independently of the effects of supplementation. Plasma ferritin concentrations were higher by 15.7 (raised AGP) to 21.2 (raised CRP and AGP) micro g/L in infants with elevated acute phase proteins compared with infants without acute phase response (P < 0.001). In contrast, plasma concentrations of retinol were lower by 0.07 (P < 0.05, raised AGP) to 0.12 (P < 0.01, raised CRP) micro mol/L, and of zinc lower by 1.49 (P < 0.01, raised AGP) to 1.89 (P < 0.05, raised CRP and AGP) micro mol/L. Hemoglobin concentrations and the modified relative dose response were not affected. Consequently, the prevalence of iron deficiency anemia was underestimated in infants with raised acute phase proteins by >15%, whereas the prevalence of vitamin A deficiency was overestimated by >16% compared with infants without acute phase response. Hence, using indicators of micronutrient status without considering the effects of the acute phase response results in a distorted estimate of micronutrient deficiencies, whose extent depends on the prevalence of infection in the population.

Lack of influence of red palm oil on severity of malaria infection in pre-school Nigerian children

Vitamin A supplements are reported to reduce febrile episodes of malaria and parasite counts, especially in children aged 12-36 months. Red palm oil (RPO) is a good source of vitamin A, is rich in alpha- and beta-carotene and is as effective as high-dose retinyl palmitate supplements in improving vitamin A status. In western Nigeria, where malaria is endemic, RPO is widely used and consumption can be measured using plasma alpha-carotene as a proxy biomarker since there are few other prominent sources of this carotene in the diet. The influence of RPO consumption on malaria was investigated in 207 children (aged 0-60 months) who presented with fever in August-October 1999 at several hospital clinics around Ile-Ife. Medical and anthropometric data, body temperature, parasitaemia and plasma C-reactive protein (CRP), retinol, carotenoids and tocopherols were measured in the children. Mothers were interviewed on usage of cooking oil and mosquito nets in the home, education and occupation. Most families used RPO and median plasma concentrations of both alpha-carotene (0.518 mumol/L) and beta-carotene (0.698 mumol/L) in the children were high. Using body temperature, parasite density and plasma CRP as markers of disease severity, multiple linear regression analysis was carried out on those for whom complete data were available (n = 138), separated into 3 age-groups of < 12 months (n = 37), 12-36 months (n = 68) and > 36 months (n = 33). In the absence of plasma retinol, plasma alpha-carotene explained 13.9% of the variance in parasite density (P = 0.013) but only in children aged > 36 months. The relationship with disease severity was negative, i.e., there was some evidence that RPO usage protected against malaria, and other dietary indices generally indicated that better nutritional status was associated with a lower severity of malaria.

Vitamin A, infection, and immune function

In populations where vitamin A availability from food is low, infectious diseases can precipitate vitamin A deficiency by decreasing intake, decreasing absorption, and increasing excretion. Infectious diseases that induce the acute-phase response also impair the assessment of vitamin A status by transiently depressing serum retinol concentrations. Vitamin A deficiency impairs innate immunity by impeding normal regeneration of mucosal barriers damaged by infection, and by diminishing the function of neutrophils, macrophages, and natural killer cells. Vitamin A is also required for adaptive immunity and plays a role in the development of T both-helper (Th) cells and B-cells. In particular, vitamin A deficiency diminishes antibody-mediated responses directed by Th2 cells, although some aspects of Th1-mediated immunity are also diminished. These changes in mucosal epithelial regeneration and immune function presumably account for the increased mortality seen in vitamin A-deficient infants, young children, and pregnant women in many areas of the world today.

Inflammation-induced changes in the nutritional biomarkers serum retinol and carotenoids

Inflammation causes a decrease in serum retinol and carotenoids as a consequence of the acute phase response of the organism. Under normal conditions both the acute phase response and the alterations in dynamics of retinol and carotenoids are transient. For both retinoids and carotenoids the adaptive benefit or the principal mechanism causing this decrease are not clear. Because nutritional deficiency results in a similar decrease of these nutritional biomarkers, it is necessary to be able to differentiate between inflammation or nutrition deficiency as the cause. This is of importance with regard to the supplementation of both critically ill patients and populations with a high infection load. The review covers several very recent publications shedding new light on and expanding our knowledge of the interaction between inflammation and the decrease in serum retinol and carotenoids.

Micronutrients and child health: studies in international nutrition and HIV infection

Increasing data link micronutrient deficiencies to excess childhood morbidity and mortality, and similar relationships have been noted in the study of nutrition and HIV infection. We review epidemiologic studies that have examined the relationship between micronutrient deficiencies and health outcomes in childhood and HIV infection, as well as clinical trials of micronutrient supplementation. Vitamin A supplementation among communities at risk of deficiency effectively reduces mortality and morbidity in children younger than age 5, and vitamin A may be especially effective in HIV-infected children. Vertical transmission of HIV has not to date been affected by maternal micronutrient supplementation. In children with poor dietary zinc intake and/or bioavailability, zinc supplementation reduces the incidence and severity of diarrheal diseases, as well as the occurrence of pneumonia. Vitamin A therapy has not been associated with improved growth, whereas some trials have shown that zinc supplementation is associated with greater increments in height. Further trials of micronutrient supplementation are warranted.