Hepatic Vitamin A Concentrations and Association with Infectious Causes of Child Death.

OBJECTIVES: To assess postmortem vitamin A (VA) concentrations in children under 5 years of age and evaluate the association between VA deficiency (VAD) and infectious causes of death (CoD). STUDY DESIGN: In this cross-sectional study from the Child Health and Mortality Prevention Surveillance (CHAMPS) Network, liver biopsies collected within 72 hours of death were analyzed from 405 stillbirths and children under 5 years in Kenya and South Africa. Total liver VA (TLVA) concentrations were quantified using ultra-performance liquid chromatography, and cutoffs of ≤0.1 µmol/g, >0.1 to <0.7 µmol/g, ≥0.7 to <1.0 µmol/g, and ≥1.0 µmol/g were used to define VAD, adequate VA status, high VA, and hypervitaminosis A, respectively. CoD were determined by expert panel review. RESULTS: Among 366 liver samples with viable extraction, pooled prevalences of VAD, adequacy, high VA, and hypervitaminosis were 34.2%, 51.1%, 6.0%, and 8.7%, respectively. VAD was more common among neonates compared with stillbirths, infants, or children, and among those with low birthweight (LBW), underweight, or stunting (P < .05). When adjusting for site, age, and sex, there was no significant association of VAD with increased infectious CoD (OR 1.9, 95% confidence interval [CI] 0.9, 3.8, P = .073). In stratified analyses, VA deficient boys, but not girls, had an increased risk of infectious CoD (OR 3.4, 95% CI 1.3, 10.3, P = .013). CONCLUSIONS: Definitive postmortem assessment of VA status identified both VAD and VA excess among children under 5 years of age in Kenya and South Africa. VAD in boys was associated with increased risk of infectious mortality. Our findings may inform a transition from universal VA supplementation (VAS) to targeted strategies in certain countries.

Breast Milk Retinol Concentrations Reflect Total Liver Vitamin A Reserves and Dietary Exposure in Thai Lactating Women from Urban and Rural Areas.

BACKGROUND: Measuring vitamin A (VA) status during lactation is required to inform dietary recommendations. Limited data exist on VA stores in women. OBJECTIVES: Our objective was to assess VA status in lactating Thai women by measuring total body VA stores (TBSs), serum and breast milk retinol concentrations, and dietary intake. METHODS: Lactating women (n = 94), 6-8 wk postpartum, were enrolled from rural (Ayutthaya) and urban (Bangkok) areas. TBSs were measured by the 13C-retinol isotope dilution (RID) technique using 2.0 µmol 13C-retinyl acetate and a single blood sample 14 d post-dose. Natural 13C-enrichment was determined in nonenrolled women (n = 11). Estimated total liver VA reserves (TLRs) were determined using assumptions for lactation. Serum, foremilk, and hindmilk samples were analyzed for retinol by HPLC. Dietary VA intake was assessed by FFQ and 24-h dietary recalls for 3 d. Multiple regression and Pearson correlation were used to evaluate relations. RESULTS: Median VA intakes were 51.8% of 2003 Thai daily recommendations for lactating women, with the majority from animal-source foods. Many women in Ayutthaya consumed liver weekly. Considering TLRs as 50% TBS, 20% and 11% of mothers in Ayutthaya and Bangkok, respectively, showed deficient reserves (≤0.10 µmol retinol/g). Median (quartile 1, quartile 3) serum [1.58 (1.34, 1.91) and 1.52 (1.30, 1.70) µmol/L] and milk [1.88 (1.29, 2.95) and 1.74 (0.96, 2.26) µmol/L] retinol in Ayutthaya and Bangkok, respectively, were normal. Women with deficient TLRs showed low milk retinol concentrations (≤1.0 µmol/L) and consumed less dietary VA, especially from animal-source foods. Breast milk retinol concentrations, especially hindmilk, demonstrated strong correlation with TBSs and TLRs estimated from the RID test. CONCLUSIONS: Approximately 15% of Thai lactating women had deficient TLRs. Breast milk retinol concentrations in conjunction with dietary intake records show potential to screen mothers at risk of VA deficiency to guide interventions.The Thai Clinical Trials Registry number is TCTR20160824001 for the work in Thailand.

Comparison of Total Body Vitamin A Stores Using Individual versus Population 13C-Natural Abundance of Serum Retinol in Preschool Children and Women Residing in 6 Diverse African Countries.

BACKGROUND: Stable isotope techniques using 13C to assess vitamin A (VA) dietary sources, absorption, and total body VA stores (TBSs) require determination of baseline 13C abundance. 13C-natural abundance is approximately 1.1% total carbon, but varies with foods consumed, supplements taken, and food fortification with synthetic retinyl palmitate. OBJECTIVES: We determined 13C variation from purified serum retinol and the resulting impact on TBSs using pooled data from preschool children in Burkina Faso, Cameroon, Ethiopia, South Africa, Tanzania, and Zambia and Zambian women. METHODS: Seven studies included children (n = 639; 56 ± 25 mo; 48% female) and one in women (n = 138; 29 ± 8.5 y). Serum retinol 13C-natural abundance was determined using GC-C-IRMS. TBSs were available in 7 studies that employed retinol isotope dilution (RID). Serum CRP and α1-acid-glycoprotein (AGP) were available from 6 studies in children. Multivariate mixed models assessed the impact of covariates on retinol 13C. Spearman correlations and Bland-Altman analysis compared serum and milk retinol 13C and evaluated the impact of using study- or global-retinol 13C estimates on calculated TBSs. RESULTS: 13C-natural abundance (%, median [Q1, Q3]) differed among countries (low: Zambia, 1.0744 [1.0736, 1.0753]; high: South Africa, 1.0773 [1.0769, 1.0779]) and was associated with TBSs, CRP, and AGP in children and with TBSs in women. 13C-enrichment from serum and milk retinol were correlated (r = 0.52; P = 0.0001). RID in children and women using study and global estimates had low mean bias (range, -3.7% to 2.2%), but larger 95% limits of agreement (range, -23% to 37%). CONCLUSIONS: 13C-natural abundance is different among human cohorts in Africa. Collecting this information in subgroups is recommended for surveys using RID. When TBSs are needed on individuals in clinical applications, baseline 13C measures are important and should be measured in all enrolled subjects.

Association between Biomarkers of Inflammation and Total Liver Vitamin A Reserves Estimated by 13C-Retinol Isotope Dilution among Preschool Children in 5 African Countries.

BACKGROUND: Vitamin A (VA) assessment is important for targeting public health programs. Retinol isotope dilution (RID) is a sensitive method to estimate total body VA stores (TBSs) and total liver reserves (TLRs), but the impact of subclinical inflammation on RID is unclear. OBJECTIVE: We determined the association between TBSs and TLRs, estimated by RID, and inflammation among preschool children without clinical infection in Burkina Faso, Cameroon, Ethiopia, South Africa, and Tanzania. METHODS: Five studies (n = 532; 47.9 ± 8.3 mo; 49.0% male) included 13C-RID and measurement of inflammation markers, CRP, and α1-acid glycoprotein (AGP). Spearman correlations were used to evaluate TBSs and TLRs with inflammation biomarkers. Wilcoxon and Kruskal-Wallis tests were used to compare TBSs and TLRs by inflammation categories [normal vs. elevated CRP (>5 mg/L) or AGP (>1 g/L)] and inflammation stage [reference, incubation (elevated CRP), early convalescence (elevated CRP and AGP), and late convalescence (elevated AGP)]. RESULTS: Complete data were available for 439 children. Median (Q1, Q3) TLRs ranged from 0.12 (0.07, 0.18) µmol/g in Ethiopia to 1.10 (0.88, 1.38) µmol/g in South Africa. Elevated CRP ranged from 4% in Burkina Faso to 42% in Cameroon, and elevated AGP from 20% in Tanzania to 58% in Cameroon. Pooled analysis (excluding Cameroon) showed a negative correlation between TBSs and AGP (ρ = -0.131, P = 0.01). Children with elevated AGP had higher probability of having lower TBSs (probability = 0.61, P = 0.002). TBSs differed among infection stages (P = 0.020). Correlations between TLRs and CRP or AGP were not significant. CONCLUSIONS: No indication of systematic bias in RID-estimated TLRs was found due to subclinical inflammation among preschool children. The inverse relationship between TBSs and AGP may reflect decreased stores after infection or an effect of inflammation on isotope partitioning. Further research should investigate potential confounding variables to improve TBS-estimate validity.

An Electronic Data Capture Framework (ConnEDCt) for Global and Public Health Research: Design and Implementation.

BACKGROUND: When we were unable to identify an electronic data capture (EDC) package that supported our requirements for clinical research in resource-limited regions, we set out to build our own reusable EDC framework. We needed to capture data when offline, synchronize data on demand, and enforce strict eligibility requirements and complex longitudinal protocols. Based on previous experience, the geographical areas in which we conduct our research often have unreliable, slow internet access that would make web-based EDC platforms impractical. We were unwilling to fall back on paper-based data capture as we wanted other benefits of EDC. Therefore, we decided to build our own reusable software platform. In this paper, we describe our customizable EDC framework and highlight how we have used it in our ongoing surveillance programs, clinic-based cross-sectional studies, and randomized controlled trials (RCTs) in various settings in India and Ecuador. OBJECTIVE: This paper describes the creation of a mobile framework to support complex clinical research protocols in a variety of settings including clinical, surveillance, and RCTs. METHODS: We developed ConnEDCt, a mobile EDC framework for iOS devices and personal computers, using Claris FileMaker software for electronic data capture and data storage. RESULTS: ConnEDCt was tested in the field in our clinical, surveillance, and clinical trial research contexts in India and Ecuador and continuously refined for ease of use and optimization, including specific user roles; simultaneous synchronization across multiple locations; complex randomization schemes and informed consent processes; and collecting diverse types of data (laboratory, growth measurements, sociodemographic, health history, dietary recall and feeding practices, environmental exposures, and biological specimen collection). CONCLUSIONS: ConnEDCt is customizable, with regulatory-compliant security, data synchronization, and other useful features for data collection in a variety of settings and study designs. Furthermore, ConnEDCt is user friendly and lowers the risks for errors in data entry because of real time error checking and protocol enforcement.

Community mobilization during biofortified orange maize feeding trials in Zambia.

In some societies, studies involving blood draws, oral vaccinations, or supplementation are surrounded by myths and disbeliefs. If not clarified, they may affect study implementation and negatively impact the outcome of well-intended studies from inadequate participation. Through participatory action research, this paper suggests how future trials could be enhanced with reference to community mobilization, drawing from the experience of two interventions in Zambian children with nutritionally enhanced, biofortified orange maize conducted by the National Food and Nutrition Commission and Tropical Diseases Research Center (Zambia), and University of Wisconsin-Madison (USA). The preparatory phase included site visits, signing of a Memorandum of Understanding, equipment inventory, hiring staff, and community meetings. Prior results were shared before the second intervention. After Institutional Review Boards' approval of procedures, written informed consent was obtained from caregivers. There was overwhelming community participation attributed to the demystification that the project was run by satanists prior to and during the study. Participation led to excellent compliance with 92.8 and 96.4% of subjects completing the final blood draw in 2010 and 2012, respectively. The results of the trials were successfully shared with the district officials and communities from where the study participants were drawn. The positive response by partners and communities, including information sharing, suggests that community mobilization, with the use of varied methods, is effective for full participation of the target groups in feeding trials and would be the case in similar trials if effectively carried out. Community participation in research studies may result in long-term adoption of biofortified foods.

Duration of Retinol Isotope Dilution Studies with Compartmental Modeling Affects Model Complexity, Kinetic Parameters, and Calculated Vitamin A Stores in US Women.

Background: Retinol isotope dilution (RID) indirectly estimates vitamin A (VA) status. Multicompartment modeling of RID data is used to refine study designs and equations to calculate VA stores. Previous studies suggest that VA in slowly turning over pools is not traced if follow-up is not long enough; however, shorter RID studies are being investigated. Few long-term models have been published. Objective: We determined the effect of time on mathematical models of VA kinetics, model parameters, and outcomes. Methods: In this longitudinal study, women (mean ± SD age: 22 ± 3 y; n = 7) were given 2.0 µmol [14,15]-13C2-retinyl acetate. Blood samples were staggered from 4 h to 152 d; the fraction of dose in serum was modeled with compartmental models. Four model-time categories were created: full models that used all data (median: 137 d; range 97-152 d) and truncated shorter studies of 14, 27, and 52 d (range: 42-62 d). Outcomes included number of compartments to adequately model serum data, kinetic parameters, total traced VA mass, and time-to-dose equilibration. To gain insight into longer follow-up, an additional participant was given 17.5 µmol 13C4-VA, and data were modeled as long as enrichment was above baseline (5 y). Results: Longer follow-up times affected kinetic parameters and outcomes. Compared with the 14-d models, long-term full models required an additional compartment for adequate fit (14.3% compared with 100%; P = 0.0056) and had longer [median (quartile 1, quartile 3)] whole-body half-life [15.0 d (10.5, 72.6 d) compared with 135 d (115, 199 d); P = 0.0006], time-to-dose equilibration [3.40 d (3.14, 6.75 d) compared with 18.9 d (11.2, 25.7 d); P < 0.0001], and total traced mass [166 µmol VA (162, 252 µmol VA) compared with 476 µmol VA (290, 752 µmol VA); P = 0.0031]. Conclusions: Extended RID sampling alters numerous mathematically modeled, time-dependent outcomes in women. Length of study should be considered when using mathematical models for calculating total-body VA stores or kinetic parameters related to VA turnover. This study is registered at www.clinicaltrials.gov as NCT03248700.

Maize Milling Method Affects Growth and Zinc Status but Not Provitamin A Carotenoid Bioefficacy in Male Mongolian Gerbils.

Background: Vitamin A (VA) and zinc deficiencies are prevalent. Maize is a common staple, and milling affects nutrient and nutrient-modifier profiles.Objective: We investigated the interaction of maize milling methods (i.e., whole grain compared with refined) in male Mongolian gerbils aged 29-35 d with conventionally bred provitamin A-biofortified (orange) or white maize on VA and zinc status.Methods: Study 1 (n = 67) was a 2 × 3 milling (whole compared with refined) by VA [no-vitamin A placebo group (VA-), orange, and VA-supplemented group (VA+)] design, with 4 wk of VA depletion followed by six 4-wk treatments (n = 10/treatment). Study 2 (n = 33) was a 2 × 2 milling-by-zinc [no-zinc placebo group (Zn-) compared with zinc-supplemented group (Zn+)] design, including 2 wk of VA depletion followed by four 3-wk treatments (n = 8-9/treatment). For study 1, positive and negative control groups were given supplemental VA at equimolar amounts to ß-carotene equivalents consumed by the orange groups (74 ± 5 nmol/d) or placebo, respectively. For study 2, positive and negative control groups were given 152 µg Zn/d or placebo, respectively.Results: Milling significantly affected zinc concentration, providing 44-45% (whole grain) or 9-14% (refined) NRC requirements. In study 1, orange maize improved liver VA concentrations (mean ± SD: 0.28 ± 0.08 µmol/g) compared with the white maize groups (0.072 ± 0.054 µmol/g). Provitamin A bioefficacy was similar. In study 2, neither zinc nor milling influenced liver retinol. Refined Zn- gerbils weighed less than others by day 14 (46.6 ± 7.1 compared with 56.5 ± 3.5 g, respectively; P < 0.0001). Milling affected pancreas zinc concentrations (refined Zn-: 21.1 ± 1.8 µg Zn/g; whole Zn-: 32.5 ± 5.8 µg Zn/g).Conclusions: Whole-grain intake improved zinc and did not affect provitamin A bioefficacy. Other factors affected by milling (e.g., shelf life, preference, aflatoxin fractioning) need to be considered to maximize health.

Single High-Dose Vitamin A Supplementation to Neonatal Piglets Results in a Transient Dose Response in Extrahepatic Organs and Sustained Increases in Liver Stores.

Background: Neonatal vitamin A (VA) supplementation is being evaluated as a public health policy for preventing infant mortality, but inconsistencies in mortality trials demand mechanistic work to determine biological plausibility.Objectives: We investigated the absorption, distribution, and storage of single large oral VA doses administered shortly after birth.Methods: Fifty pregnant sows (Sus scrofas domesticas) were fed a VA-free diet. Male and female newborn piglets (n = 313) were orally administered 0, 25,000, 50,000, or 200,000 IU VA in oil within 12 h of birth when mean ± SD weight was 1.56 ± 0.25 kg. Blood was drawn to determine absorption and storage 0.5-240 h after administration. Metabolic and postnatal dose-timing substudies were performed. Liver, lung, kidney, spleen, and adrenal VA concentrations were determined 7-240 h after administration.Results: Serum retinol and retinyl ester concentrations responded to treatment (P < 0.0001); however, differences between groups disappeared by 96 h. Liver VA concentrations responded to treatment (P < 0.0001), which persisted for 240 h. Liver VA for control piglets at 10 d (mean ± SD: 0.05 ± 0.02 µmol/g) was ≤0.1 µmol/g (deficiency), whereas groups that received VA maintained concentrations >0.1 µmol/g. Extrahepatic tissue VA concentrations displayed treatment effects (P ≤ 0.0077); groups that received treatments had higher VA concentrations than controls at early time points. Lung, kidney, and spleen VA did not differ between groups by 96 h, whereas adrenal glands did not differ by 240 h. Body weight was affected by treatment (P = 0.0002); VA-deficient piglets weighed 23-29% more than all treated groups 240 h after administration.Conclusions: A high dose of VA administered to newborn piglets was well absorbed, appeared in serum primarily as retinyl esters, and was taken up dose-dependently in all tissues studied; however, enhancement did not persist in sera, lungs, kidneys, spleens, or adrenal glands. Short-term impacts of retinoid signaling on weight gain remain to be elucidated, and longer follow-up studies are needed.

13C Natural Abundance of Serum Retinol Is a Novel Biomarker for Evaluating Provitamin A Carotenoid-Biofortified Maize Consumption in Male Mongolian Gerbils.

BACKGROUND: Crops such as maize, sorghum, and millet are being biofortified with provitamin A carotenoids to ensure adequate vitamin A (VA) intakes. VA assessment can be challenging because serum retinol concentrations are homeostatically controlled and more sensitive techniques are resource-intensive. OBJECTIVES: We investigated changes in serum retinol relative differences of isotope amount ratios of (13)C/(12)C (δ(13)C) caused by natural (13)C fractionation in C3 compared with C4 plants as a biomarker to detect provitamin A efficacy from biofortified (orange) maize and high-carotene carrots. METHODS: The design was a 2 × 2 × 2 maize (orange compared with white) by carrot (orange compared with white) by a VA fortificant (VA+ compared with VA-) in weanling male Mongolian gerbils (n = 55), which included a 14-d VA depletion period and a 62-d treatment period (1 baseline and 8 treatment groups; n = 5-7/group). Liver VA and serum retinol were quantified, purified by HPLC, and analyzed by GC combustion isotope ratio mass spectrometry for (13)C. RESULTS: Treatments affected liver VA concentrations (0.048 ± 0.039 to 0.79 ± 0.24 µmol/g; P < 0.0001) but not overall serum retinol concentrations (1.38 ± 0.22 µmol/L). Serum retinol and liver VA δ(13)C were significantly correlated (R(2) = 0.92; P < 0.0001). Serum retinol δ(13)C differentiated control groups that consumed white maize and white carrots (-27.1 ± 1.2 δ(13)C‰) from treated groups that consumed orange maize and white carrots (-21.6 ± 1.4 δ(13)C‰ P < 0.0001) and white maize and orange carrots (-30.6 ± 0.7 δ(13)C‰ P < 0.0001). A prediction model demonstrated the relative contribution of orange maize to total dietary VA for groups that consumed VA from mixed sources. CONCLUSIONS: Provitamin A efficacy and quantitative estimation of the relative contribution to dietary VA were demonstrated with the use of serum retinol δ(13)C. This method could be used for maize efficacy or effectiveness studies and with other C4 crops biofortified with provitamin A carotenoids (e.g., millet, sorghum). Advantages include no extrinsic tracer dose, 1 blood sample, and higher sensitivity than serum retinol concentrations alone.

Biomarkers of Nutrition for Development (BOND)-Vitamin A Review.

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-informed advice to anyone with an interest in the role of nutrition in health. The BOND program provides information with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect, which will be especially useful for readers who want to assess nutrient status. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutritional status at the individual and population levels. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, folate, zinc, iron, vitamin A, and vitamin B-12. This review of vitamin A is the current article in this series. Although the vitamin was discovered >100 y ago, vitamin A status assessment is not trivial. Serum retinol concentrations are under homeostatic control due in part to vitamin A's use in the body for growth and cellular differentiation and because of its toxic properties at high concentrations. Furthermore, serum retinol concentrations are depressed during infection and inflammation because retinol-binding protein (RBP) is a negative acute-phase reactant, which makes status assessment challenging. Thus, this review describes the clinical and functional indicators related to eye health and biochemical biomarkers of vitamin A status (i.e., serum retinol, RBP, breast-milk retinol, dose-response tests, isotope dilution methodology, and serum retinyl esters). These biomarkers are then related to liver vitamin A concentrations, which are usually considered the gold standard for vitamin A status. With regard to biomarkers, future research questions and gaps in our current understanding as well as limitations of the methods are described.

Comparisons among Equations Used for Retinol Isotope Dilution in the Assessment of Total Body Stores and Total Liver Reserves.

Vitamin A plays an essential role in animal biology and has negative effects associated with both hypo- and hypervitaminosis A. Many notable interventions are being done globally to eliminate vitamin A deficiency, including supplementation, fortification, and biofortification. At the same time, it is important to monitor vitamin A status in nations where preformed vitamin A intake is high because of consumption of animal source foods (e.g., liver, dairy, eggs), fortified foods (e.g., milk, cereals, oil, sugar, margarine), or vitamin supplements (e.g., one-a-day multivitamins) to ensure the population does not reach hypervitaminosis A. To accurately assess population status and evaluate interventions aimed at improving vitamin A status, accurate assessment methods are needed. The primary storage site of vitamin A is the liver; however, routinely obtaining liver samples from humans is impractical and unethical. Isotope dilution using deuterium- or (13)C-labeled retinol is currently the most sensitive indirect biomarker of vitamin A status across a wide range of liver reserves. The major drawback to its application is the increased technicality in sample analysis and data calculations when compared to less sensitive methodology, such as serum retinol concentrations and dose response tests. Two main equations have emerged for calculating vitamin A body pool size or liver concentrations from isotope dilution data: the "Olson equation" and the "mass balance equation." Different applications of these equations can lead to confusion and lack of consistency if the underlying principles and assumptions used are not clarified. The purpose of this focused review is to describe the evolution of the equations used in retinol stable-isotope work and the assumptions appropriate to different applications of the test. Ultimately, the 2 main equations are shown to be fundamentally the same and differ only in assumptions made for each specific research application.

Racial disparities in selected micronutrient deficiencies after bariatric surgery: A systematic review.

BACKGROUND: Bariatric surgery has been associated with numerous micronutrient deficiencies. Several observational studies have found that these deficiencies are more common in racially/ethnically minoritized patients. OBJECTIVES: To conduct a systematic review to investigate whether racially/ethnically minoritized patients experience worse nutritional outcomes after bariatric surgery. SETTING: University of Wisconsin-Madison. METHODS: PubMed, CINAHL, PsychINFO, and Cochrane databases were queried. We searched for manuscripts that reported micronutrient levels or conditions related to micronutrient deficiencies according to race/ethnicity (White, African American/Black, and Hispanic) after laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass between 2002 and 2022. Eleven micronutrients (vitamins A, B1 [thiamine], B12, D, E, K, calcium, copper, folate, iron, and zinc), and four conditions (anemia, bone loss, fractures, and hyperparathyroidism) were assessed. RESULTS: Abstracts from 953 manuscripts were screened; 18 full-text manuscripts were reviewed for eligibility, and ten met the inclusion criteria. Compared to White patients, African Americans had a higher prevalence of thiamine, vitamin D, and vitamin A deficiencies. There were no differences in calcium and vitamin B12 deficiencies. The other six micronutrients were not assessed according to race/ethnicity. Hyperparathyroidism was more prevalent in African Americans than White patients in the three studies that evaluated it. The prevalence of fractures was mixed. Anemia and bone loss were not evaluated according to race/ethnicity. CONCLUSIONS: Although the literature on micronutrient outcomes following bariatric surgery according to race/ethnicity is limited, African Americans appear to experience a higher prevalence of vitamin deficiencies and associated conditions. Qualitative and quantitative research to explore these disparities is warranted.

Portable Devices for Measurement of Vitamin A Concentrations in Edible Oil: Field Readiness of Available Options.

Vitamin A (VA) deficiency continues to be a major global health issue, despite measures to increase VA intake via consumption of staple foods such as edible oil. Portable quantitative and semiquantitative devices or test kits for internal quality control have the potential to overcome some of the limitations of traditional methods of testing, such as centralized laboratory, expensive equipment, and specially trained staff. This landscape analysis and comprehensive systematic mini-review catalogs and summarizes evidence on the analytical performance of portable quantitative and semiquantitative devices and test kits for the analysis of VA in edible oil. Studies or reports detailing the usability and validation of portable devices and/or test kits, as well as studies comparing device/test kit performance to a reference standard such as high-performance liquid chromatography (HPLC), were included. Identified devices and test kits were compared for performance versus the reference standard, usability, availability, and other characteristics. We identified four portable methods: two devices, the iCheck CHROMA and iCheck Chroma 3 from BioAnalyt; and two test kits, the QuickView from Bagco Enterprises and the Strategic Alliance for the Fortification of Vegetable Oils (SAFO) Test Kit by Badische Anilin and Soda Fabrik (BASF). Included studies reported the following: an internal validation of the portable method, a comparison of the portable method against a reference standard, a comparison of the portable method against another portable method, and several videos and company websites, which detailed device characteristics. iCheck CHROMA and QuickView quantified VA concentrations with high accuracy and precision compared to the reference standard for field-based quantification, were user-friendly, and provided results within 5 min. iCheck Chroma 3 requires more robust validation against a reference standard. We did not find data on internal validation or comparison against a reference standard for the current version of the SAFO test. Compared to QuickView and SAFO, the iCheck devices can transfer results to a hard drive or the Web, have an online order form for purchase, and meet a minimal set of criteria for point-of-need devices. iCheck, QuickView, and SAFO can quantify VA concentrations in the edible oils tested and determine whether a fortified oil meets country standards. Additional research is needed to validate these devices and test kits across additional oil types and document the ability to meet the minimal criteria for point-of-need devices suggested in this mini-review. Validation against a reference standard is required for SAFO. The limited number of portable methods available may be due to market saturation. Future market and use case analyses to inform the market size and utility of the different tests with publicly available data will allow new manufacturers, particularly those in lower-to-middle-income countries, to enter the market.

A review of portable quantitative and semi-quantitative devices for measurement of vitamin A in biological samples.

Background: We catalog and summarize evidence of the analytical performance of portable quantitative and semi-quantitative devices for the assessment of vitamin A status and vitamin A deficiency (VAD) in various biological samples-including whole blood, plasma, serum, and milk-in addition to VAD determination by functional indicators such as pupillary response. Methods: We searched the literature for published research articles, patents, and information from manufacturers of mobile devices, particularly those appropriate for low-resource settings. The included devices were required to be portable (lightweight and ideally not needing a power outlet) and to measure vitamin A as well as define VAD. Eligible studies compared a portable device to a reference standard of high-performance liquid chromatography for blood and milk, or a Goldmann-Weekers dark adaptometer for eyes/vision. Where available, identified devices were compared with reference methods across several performance criteria. When possible, we compared the device's performance reported in published studies against the stated performance criteria from the manufacturers' websites. Results: We catalogued 25 portable devices for measuring vitamin A and/or VAD via biological samples. We also identified 18 comparison studies (plus associated reports) assessing nine methods: the iCheck Fluoro, iCheck Carotene, CRAFTi, Tidbit with or without the HYPER filtration system, custom field-friendly immunoassays, and microfluidic assays for blood; the iCheck Fluoro and iCheck Carotene for milk; and the Scotopic Sensitivity Tester-1 for eye function. Conclusions: The iCheck Fluoro and iCheck Carotene are commercially available for use and are acceptable for measuring vitamin A in blood and milk samples, according to the available validation data. Many of the other identified devices, including other portable fluorometers, photometers, immunoassays, microfluidics-based devices, and dark adaptometers, were proofs of concept and not yet commercially available. Furthermore, none of these other devices included manufacturer-described device performance criteria to compare with descriptions from experimental studies. Several gaps remain, including studies comparing the other portable devices against a reference standard, particularly for functional indicators of vitamin A status/deficiency; available manufacturer-reported device performance criteria against which to compare future results of investigations; and more comprehensive reporting of validation metrics including sensitivity, specificity, precision, and Bland-Altman analysis.

Iron Bioavailability from Multiple Biofortified Foods Using an In Vitro Digestion, Caco-2 Assay for Optimizing a Cyclical Menu for a Randomized Efficacy Trial.

BACKGROUND: Inadequate nutritional status contributes to substantial losses in human health and productivity globally. A multiple biofortified food crop trial targeting iron, zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is being conducted in India. OBJECTIVE: We sought to determine the relative iron bioavailability from biofortified and conventional crops and crop combinations representative of a cyclical menu using crops targeted for inclusion in the feeding trial. METHODS: Crops were procured from India, cooked, freeze-dried, and analyzed with an established in vitro digestion/Caco-2 iron bioavailability assay using a fixed sample weight. Crop proportions representative of meals planned for the human study were determined and combined such that samples included either all biofortified or all control crops. Crops were analyzed as single crops (n = 4) or crop combinations (n = 7) by variety (biofortified or control) in triplicate. The primary outcome was iron uptake measured by Caco-2 ferritin production normalized to total Caco-2 protein (nanograms of ferritin/milligrams of cell protein) analyzed for effects of crop variety and crop proportion using generalized linear models. RESULTS: Biofortified pearl millet alone demonstrated higher iron uptake than conventional varieties (5.01 ± 1.66 vs. 2.17 ± 0.96; P = 0.036). Addition of sweet potato or sweet potato + pulse improved iron uptake for all proportions tested in control varieties and select proportions for biofortified varieties (P ≤ 0.05). Two multiple crop combinations demonstrated modestly higher iron uptake from biofortified crops. CONCLUSIONS: Optimizing total iron delivery should consider matrix effects, processing, and promoters/inhibitors of iron absorption in addition to total iron concentration. Future directions include evaluating recipes as prepared for consumption and comparison against human iron bioavailability studies.

Metabolism of Neonatal Vitamin A Supplementation: A Systematic Review.

A systematic review was conducted to summarize the absorption, transport, storage, and metabolism of oral neonatal vitamin A supplementation (NVAS). This review focused specifically on the neonatal period (first 28 d of life for humans) to inform guidance by WHO on recommendations related to NVAS. A systematic search of international and regional databases was conducted. Inclusion criteria were human or animal studies that gave oral vitamin A as a single or limited number of doses to apparently healthy neonates. Studies evaluating fortification or food-based approaches, dosing with retinoic acid, or studies of neonatal models of disease were excluded. The search retrieved 8847 unique records. After screening by title and abstract, 88 were screened using the full text, and 35 records met inclusion criteria: 13 human and 22 animal studies. Studies indicate that high-dose NVAS is absorbed well by neonates, typically mirroring fat absorption. Doses were primarily stored in the liver and transiently increased in the lung, kidney, spleen, adrenal glands, brain, skin, and adipose tissue, generally with a dose-response. Serum retinol and retinyl esters also transiently increased following NVAS. Although minimal acute adverse effects are noted, there is a lack of data supporting NVAS for improving organ maturation or sustained delivery to target organs. Research gaps include the physiological effects of the short-term increase of vitamin A concentrations in extrahepatic tissues, or whether there are unknown adverse effects over time.

Findings in 3 clinical trials challenge the accuracy of the Institute of Medicine's estimated average requirements for vitamin A in children and women.

BACKGROUND: Vitamin A (VA) estimated average requirements (EARs) for women and children are extrapolated from rats and adult males. The retinol isotope dilution (RID) test can sensitively characterize VA status and intake requirements. OBJECTIVES: These studies evaluated current EARs for children 4-8 y and women 19-30 y old. METHODS: Zambian children (n = 133, ages 5-7 y), US women (n = 51, ages 19-27 y), and Indonesian women (n = 29, ages 19-30 y) were provided diets or supplements containing 30%-155% of VA EARs for 42-90 d. RID was performed before and after the intervention to quantify changes in total body VA stores (TBSs) and total liver VA reserves (TLRs). Linear regression was performed between VA intake and change in TBSs or TLRs. RESULTS: Baseline mean ± SD TLRs were hypervitaminotic in Zambian children (1.13 ± 0.41 µmol VA/g liver), optimal in US women (0.46 ± 0.32 µmol/g VA/g liver), and deficient to marginal in Indonesian women (0.10 ± 0.08 µmol VA/g liver). VA intakes, resulting in no change in TBSs or TLRs, were 185 (95% CI: 18, 288) or 257 (95% CI: 124, 411) and 285 or 330 (CIs undefined) µg retinol activity equivalents (RAE)/d in the Zambian and US trials, respectively, but inconclusive in Indonesian women. The regression was not significant in either group of women. CONCLUSIONS: Point estimates of VA intakes to maintain stores were below the current EARs of 275 (children) and 500 (women) µg RAE/d despite the TLRs being higher than the EARs were formulated to maintain (i.e., 0.07 µmol VA/g liver). Interventions based on these EARs may need to be scaled back. Lack of change in VA stores in women taking lower doses may result from physiological adaptation resulting in lower VA utilization. Longer, larger, and controlled studies are needed to accurately define EARs for VA.These trials were registered at Clinicaltrials.gov as NCT04123210 and NCT01814891.

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.