Potential Mechanisms of Precision Nutrition-Based Interventions for Managing Obesity.

Precision nutrition (PN) considers multiple individual-level and environmental characteristics or variables to better inform dietary strategies and interventions for optimizing health, including managing obesity and metabolic disorders. Here, we review the evidence on potential mechanisms-including ones to identify individuals most likely to respond-that can be leveraged in the development of PN interventions addressing obesity. We conducted a review of the literature and included laboratory, animal, and human studies evaluating biochemical and genetic data, completed and ongoing clinical trials, and public programs in this review. Our analysis describes the potential mechanisms related to 6 domains including genetic predisposition, circadian rhythms, physical activity and sedentary behavior, metabolomics, the gut microbiome, and behavioral and socioeconomic characteristics, i.e., the factors that can be leveraged to design PN-based interventions to prevent and treat obesity-related outcomes such as weight loss or metabolic health as laid out by the NIH 2030 Strategic Plan for Nutrition Research. For example, single nucleotide polymorphisms can modify responses to certain dietary interventions, and epigenetic modulation of obesity risk via physical activity patterns and macronutrient intake have also been demonstrated. Additionally, we identified limitations including questions of equitable implementation across a limited number of clinical trials. These include the limited ability of current PN interventions to address systemic influences such as supply chains and food distribution, healthcare systems, racial or cultural inequities, and economic disparities, particularly when designing and implementing PN interventions in low- and middle-income communities. PN has the potential to help manage obesity by addressing intra- and inter-individual variation as well as context, as opposed to "one-size fits all" approaches though there is limited clinical trial evidence to date.

Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.

BACKGROUND: Vitamin B12 deficiency is a major public health problem worldwide, with the highest burden in elderly people, pregnant women, and young children. Due to its role in DNA synthesis and methylation, folate metabolism, and erythropoiesis, vitamin B12 supplementation during pregnancy may confer longer-term benefits to maternal and child health outcomes. OBJECTIVES: To evaluate the benefits and harms of oral vitamin B12 supplementation during pregnancy on maternal and child health outcomes. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) on 2 June 2023, and reference lists of retrieved studies. SELECTION CRITERIA: Randomised controlled trials (RCTs), quasi-RCTs, or cluster-RCTs evaluating the effects of oral vitamin B12 supplementation compared to placebo or no vitamin B12 supplementation during pregnancy. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Four review authors independently assessed trial eligibility. Two review authors independently extracted data from included studies and conducted checks for accuracy. Three review authors independently assessed the risk of bias of the included studies using the Cochrane RoB 1 tool. We used GRADE to evaluate the certainty of evidence for primary outcomes. MAIN RESULTS: The review included five trials with 984 pregnant women. All trials were conducted in low- and middle-income countries, including India, Bangladesh, South Africa, and Croatia. At enrolment, 26% to 51% of pregnant women had vitamin B12 deficiency (less than 150 pmol/L), and the prevalence of anaemia (haemoglobin less than 11.0 g/dL) ranged from 30% to 46%. The dosage of vitamin B12 supplementation varied from 5 µg/day to 250 µg/day, with administration beginning at 8 to 28 weeks' gestation through to delivery or three months' postpartum, and the duration of supplementation ranged from 8 to 16 weeks to 32 to 38 weeks. Three trials, involving 609 pregnant women, contributed data for meta-analyses of the effects of vitamin B12 supplementation compared to placebo or no vitamin B12 supplementation. Maternal anaemia: there may be little to no difference for maternal anaemia by intervention group, but the evidence is very uncertain (70.9% versus 65.0%; risk ratio (RR) 1.08, 95% confidence interval (CI) 0.93 to 1.26; 2 trials, 284 women; very low-certainty evidence). Maternal vitamin B12 status: vitamin B12 supplementation during pregnancy may reduce the risk of maternal vitamin B12 deficiency compared to placebo or no vitamin B12 supplementation, but the evidence is very uncertain (25.9% versus 67.9%; RR 0.38, 95% CI 0.28 to 0.51; 2 trials, 272 women; very low-certainty evidence). Women who received vitamin B12 supplements during pregnancy may have higher total vitamin B12 concentrations compared to placebo or no vitamin B12 supplementation (mean difference (MD) 60.89 pmol/L, 95% CI 40.86 to 80.92; 3 trials, 412 women). However, there was substantial heterogeneity (I2 = 85%). Adverse pregnancy outcomes: the evidence is uncertain about the effect on adverse pregnancy outcomes, including preterm birth (RR 0.97, 95% CI 0.55 to 1.74; 2 trials, 340 women; low-certainty evidence), and low birthweight (RR 1.50, 95% CI 0.93 to 2.43; 2 trials, 344 women; low-certainty evidence). Two trials reported data on spontaneous abortion (or miscarriage); however, the trials did not report quantitative data for meta-analysis and there was no clear definition of spontaneous abortion in the study reports. No trials evaluated the effects of vitamin B12 supplementation during pregnancy on neural tube defects. Infant vitamin B12 status: children born to women who received vitamin B12 supplementation had higher total vitamin B12 concentrations compared to placebo or no vitamin B12 supplementation (MD 71.89 pmol/L, 95% CI 20.23 to 123.54; 2 trials, 144 children). Child cognitive outcomes: three ancillary analyses of one trial reported child cognitive outcomes; however, data were not reported in a format that could be included in quantitative meta-analyses. In one study, maternal vitamin B12 supplementation did not improve neurodevelopment status (e.g. cognitive, language (receptive and expressive), motor (fine and gross), social-emotional, or adaptive (conceptual, social, practical) domains) in children compared to placebo (9 months, Bayley Scales of Infant and Toddler Development Third Edition (BSID-III); 1 trial; low-certainty evidence) or neurophysiological outcomes (72 months, event-related potential measures; 1 trial; low-certainty evidence), though children born to women who received vitamin B12 supplementation had improved expressive language domain compared to placebo (30 months, BSID-III; 1 trial; low-certainty evidence). AUTHORS' CONCLUSIONS: Oral vitamin B12 supplementation during pregnancy may reduce the risk of maternal vitamin B12 deficiency and may improve maternal vitamin B12 concentrations during pregnancy or postpartum compared to placebo or no vitamin B12 supplementation, but the evidence is very uncertain. The effects of vitamin B12 supplementation on other primary outcomes assessed in this review were not reported, or were not reported in a format for inclusion in quantitative analyses. Vitamin B12 supplementation during pregnancy may improve maternal and infant vitamin B12 status, but the potential impact on longer-term clinical and functional maternal and child health outcomes has not yet been established.

A Randomized Trial of Quadruple-Fortified Salt for Anemia and Birth Defects Prevention in Southern India: Protocol Design and Methods.

Background: Women of reproductive age are at an increased risk of anemia and micronutrient deficiencies. Evidence supports the role of periconceptional nutrition in the development of neural tube defects (NTDs) and other pregnancy complications. Vitamin B12 deficiency is a risk factor for NTDs and may modify folate biomarkers that predict NTD risk at the population level. There is an interest in mandatory fortification with vitamin B12 and folic acid for anemia and birth defect prevention. However, there are limited population-representative data needed to inform policy and guidelines. Objectives: This randomized trial will be conducted to evaluate the efficacy of quadruple-fortified salt (QFS; iron, iodine, folic acid, vitamin B12) in 1,000 households in Southern India. Methods: Women 18 to 49 y who are not pregnant or lactating and reside within the catchment area of our community-based research site in Southern India will be screened and invited to participate in the trial. After informed consent, women and their households will be randomized to receive one of the following 4 interventions: 1) double-fortified salt (DFS; iron, iodine), 2) DFS + folic acid (iron, iodine, folic acid), 3) DFS + vitamin B12 (iron, iodine, vitamin B12), or 4) DFS + folic acid and vitamin B12 (QFS; iron, iodine, folic acid, vitamin B12) for 12 mo. Structured interviews will be conducted by trained nurse enumerators to collect sociodemographic, anthropometric, dietary, health, and reproductive history data. Biological samples will be collected at baseline, midpoint, and endpoint. Whole blood will be analyzed for hemoglobin using Coulter Counter. Total vitamin B12 will be measured by chemiluminescence; red blood cell folate and serum folate will be evaluated using the World Health Organization-recommended microbiologic assay. Conclusions: The results of this randomized trial will help to evaluate the efficacy of QFS to prevent anemia and micronutrient deficiencies. Clinical trial registration numbers: NCT03853304 and Clinical Trial Registry of India REF/2019/03/024479. Registration number: NCT03853304 and REF/2019/03/024479.

Estimating the serum folate concentration that corresponds to the red blood cell folate concentration threshold associated with optimal neural tube defects prevention: A population-based biomarker survey in Southern India.

BACKGROUND: RBC folate concentrations are monitored at the population level, with a recommended threshold for optimal neural tube defect (NTD) prevention. A corresponding threshold for serum folate has not been established. OBJECTIVES: This study aimed to estimate the serum folate insufficiency threshold corresponding to the RBC folate threshold for NTD prevention and examine how this threshold is modified by vitamin B12 status. METHODS: Participants were women (15-40 y; not pregnant or lactating; n = 977) from a population-based biomarker survey in Southern India. RBC folate and serum folate were measured via microbiologic assay. RBC folate deficiency (<305 nmol/L) and insufficiency (<748 nmol/L), serum vitamin B12 deficiency (<148 pmol/L) and vitamin B12 insufficiency (<221 pmol/L), elevated plasma MMA (>0.26 µmol/L), elevated plasma homocysteine (>10.0 µmol/L), and elevated HbA1c (≥6.5%) were evaluated. Bayesian linear models were used to estimate unadjusted and adjusted thresholds. RESULTS: Compared with adequate vitamin B12 status, the estimated serum folate threshold was higher in participants with serum vitamin B12 deficiency (72.5 vs. 28.1 nmol/L) or vitamin B12 insufficiency (48.7 vs. 24.3 nmol/L) and elevated MMA (55.6 vs. 25.9 nmol/L). The threshold was lower in participants with elevated HbA1c (HbA1c ≥6.5% vs. <6.5%; 21.0 vs. 40.5 nmol/L). CONCLUSIONS: The estimated serum folate threshold for optimal NTD prevention was similar to previous reports (24.3 vs. 25.6 nmol/L) among participants with sufficient vitamin B12 status. However, this threshold was more than 2-fold higher in participants with vitamin B12 deficiency and substantially higher across all indicators of insufficient vitamin B12 status (<221 pmol/L, elevated MMA, combined B12, impaired vitamin B12 status), and lower in participants with elevated HbA1c. Findings suggest a serum folate threshold for NTD prevention may be possible in some settings; however, it may not be appropriate in populations with high prevalence of vitamin B12 insufficiency. Am J Clin Nutr 2023;xx:xx-xx. This trial was registered at https://clinicaltrials.gov as NCT04048330.

Estimation of Hydration and Density of Fat-Free Mass in Indian Children Using a 4-Compartment Model: Implications for the Estimation of Body Composition Using 2-Compartment Models.

BACKGROUND: Accurate methods are needed to measure body fat mass (FM), particularly in South Asian children who are thought to have greater adiposity for a given body size. The accuracy of simple 2-compartment (2C) models of measuring FM depends on the primary measurement of the fat free mass (FFM) and the validity of assumed constants for FFM hydration and density. These have not been measured in this particular ethnic group. OBJECTIVES: To measure FFM hydration and density in South Indian children using a 4-compartment (4C) model and to compare FM estimates from this 4C-model with 2C-model-based estimates from hydrometry and densitometry, using literature-reported FFM hydration and density in children. METHODS: This study included 299 children (45% boys), aged 6-16 y from Bengaluru, India. Total body water (TBW), bone mineral content (BMC), and body volume were measured using deuterium dilution, dual-energy X-ray absorptiometry, and air displacement plethysmography, respectively, to calculate the FFM hydration and density, and the FM using 4C and 2C models. The agreement between FM estimates from 2C and 4C models was also evaluated. RESULTS: Mean FFM hydration and density were 74.2% ± 2.1% and 71.4% ± 2.0% and 1.095 ± 0.008 kg/L and 1.105 ± 0.008 kg/L in boys and girls respectively, which were significantly different from published values. Using the presently estimated constants, the mean hydrometry-based FM (as % body weight) estimates decreased by 3.5% but increased by 5.2% for densitometry-based 2C methods. When 2C-FM (using previously reported FFM hydration and density) were compared with 4C-FM estimates, the mean difference was -1.1 ± 0.9 kg for hydrometry and 1.6 ± 1.1 kg for densitometry. CONCLUSIONS: Previously published constants of hydration and density of FFM may induce errors of -12% to +17% in FM (kg) when using different 2C models in comparison to the 4C models in Indian children. J Nutr 20xx;x:xx.

Comparison of Anemia Screening Methods Using Paired Venous Samples in Women of Reproductive Age in Southern India.

BACKGROUND: Anemia is an important public health problem, and accurate estimates may inform policy and programs. Although hemoglobin (Hb) assessment of venous blood via automated hematology analyzers (AHAs) is recommended, most population-based surveys estimate anemia prevalence based on analysis of capillary blood via portable hemoglobinometers. OBJECTIVES: We aimed to evaluate screening methods for hemoglobin and anemia assessment using paired venous samples. METHODS: Participants were women 15-40 y who were not pregnant or lactating. Paired venous whole blood samples (n = 896) were analyzed for hemoglobin (Hb) via portable hemoglobinometer (HemoCue 301) and Coulter Counter AHA. Anemia and severe anemia were defined as Hb <12.0g/dL and <8.0 g/dL, respectively. Bland-Altman methods were used to assess the level of agreement for Hb results (mean difference, SD of differences, limits of agreement). Diagnostic accuracy parameters (sensitivity, specificity, positive predictive value, negative predictive value, accuracy) were calculated to evaluate HemoCue performance compared to the AHA reference, overall and by sociodemographic, nutritional, and metabolic characteristics. RESULTS: The estimated anemia prevalence was significantly lower via HemoCue vs. AHA (36.3% compared with 41.6%; P value < 0.0001). The HemoCue had 84.4% accuracy for anemia screening and 98.8% for severe anemia, compared to the AHA reference. The HemoCue had 74.8% sensitivity and 91.2% specificity, compared to AHA. HemoCue sensitivity was higher in women with iron deficiency [serum ferritin (SF) <15.0 µg/L: 81.6% compared with SF ≥15.0 µg/L: 41.3%], and lower in women with metabolic risk factors, including overweight [BMI ≥25.0 kg/m2: 63.9% vs. BMI <25.0 kg/m2: 78.8%], or elevated CRP (>1.0 mg/L: 67.2% vs. ≤1.0 mg/L: 82.9%), trunk fat (>35%: 62.7% vs. ≤35%: 80.1%), or whole-body fat (>35%: 63.9% vs. ≤35%: 80.3%). CONCLUSIONS: Findings suggest that women with anemia may be incorrectly identified as not anemic via portable hemoglobinometer, and anemia prevalence may be underestimated at the population level.This study was registered at clinicaltrials.gov as NCT04048330.

Iron, folic acid, and multiple micronutrient supplementation strategies during pregnancy and adverse birth outcomes in Botswana.

BACKGROUND: Antenatal multiple micronutrient supplementation (MMS) with iron, folic acid, and other micronutrients might improve birth outcomes, but it is not currently universally recommended by WHO. METHODS: In this observational cohort study, we surveyed pregnancies for adverse birth outcomes at eight hospitals from July, 2014, to July, 2018, and 18 hospitals from August, 2018, to December, 2020, in Botswana to assess four routine supplementation strategies in women presenting before 24 weeks' gestation: folic acid only, iron only, iron and folic acid supplementation (IFAS), and MMS. Women with singleton pregnancies; a known HIV status, age, and delivery site; haemoglobin measured within 7 days of presenting to antenatal care; and weight measured within 31 days of presenting to care were included in our analysis. Data were abstracted from the maternity obstetric record (a record of antenatal care) at the time of birth from all women giving birth at selected hospitals throughout the country. We estimated risk differences overall and in key subgroups, adjusting for demographic and clinical factors. FINDINGS: Between July 6, 2014, and Dec 8, 2020, 96 341 eligible women (21 659 [22·5%] of whom had HIV) were included in the study. 36 334 (37·7%) women initiated iron only supplementation, 1133 (11·8%) initiated folic acid only supplementation, 23 101 (24·0%) initiated IFAS, and 31 588 (32·8%) women initiated MMS. Women who initiated iron only and folic acid only supplementation had higher risks of stillbirth, preterm birth, very preterm birth, low and very low birthweight, and neonatal death compared with women who received IFAS (adjusted risk differences for iron only supplementation vs IFAS ranged from 0·22% [95% CI 0·04 to 0·40] for neonatal death to 2·39% [1·78 to 3·00] for preterm birth; and adjusted risk differences for folic acid only supplementation vs IFAS ranged from 0·77% [-0·80 to 2·34] for neonatal death to 5·75% [1·38 to 10·13] for preterm birth), with greater difference in women with HIV and those aged 35 years and older. Compared with IFAS, women who initiated MMS had lower risks of preterm and very preterm births, and low and very low birthweight (adjusted risk differences ranged from -0·50% [-0·77 to 0·23] for very preterm birth to -1·06% [-1·69 to -0·42] for preterm birth). INTERPRETATION: Nationwide data from Botswana support improved birth outcomes with MMS compared with IFAS. FUNDING: National Institutes of Health, National Institute of Child Health and Human Development, and National Institute of Allergy and Infectious Diseases.

Iron status and inflammation in women of reproductive age: A population-based biomarker survey and clinical study.

BACKGROUND: Women of reproductive age (WRA) are at increased risk for anemia and iron deficiency. However, there is limited population-level data in India, which could help inform evidence-based recommendations and policy. AIMS: To conduct a population-based biomarker survey of anemia, iron deficiency, and inflammation in WRA in Southern India. METHODS: Participants were WRA (15-40 y) who were not pregnant or lactating. Blood samples (n = 979) were collected and analyzed for hemoglobin (Hb), serum ferritin (SF), soluble transferrin receptor (sTfR), C-reactive protein (CRP), and alpha-1 acid glycoprotein (AGP). Anemia and severe anemia were defined as Hb < 12.0 and < 8.0 g/dL. Serum ferritin was adjusted for inflammation using BRINDA methods. Iron deficiency was defined as SF <15.0 µg/L, iron insufficiency was defined as SF < 20.0 and < 25.0 µg/L, and iron deficiency anemia was defined as Hb < 12.0 g/dL and SF < 15.0 µg/L. Inflammation was defined as CRP > 5.0 mg/L or AGP > 1.0 g/L. Restricted cubic spline regression models were also used to determine if alternative SF thresholds should be used t to classify iron deficiency. RESULTS: A total of 41.5% of WRA had anemia, and 3.0% had severe anemia. Findings from spline analyses suggested a SF cut-off of < 15.0 µg/L, consistent with conventional cut-offs for iron deficiency. 46.3% of WRA had SF < 15.0 µg/L (BRINDA-adjusted: 61.5%), 55.0% had SF < 20.0 µg/L (72.7%), 61.8% had SF < 25.0 µg/L (81.0%), and 30.0% had IDA (34.5%). 17.3% of WRA had CRP > 5.0 mg/L and 22.2% had AGP > 1.0 g/L. The prevalence of ID (rural vs. urban: 49.1% vs. 34.9%; p = 0.0004), iron insufficiency (57.8% vs. 43.8%; p = 0.0005), and IDA (31.8% vs. 22.4%; p = 0.01) were significantly higher in rural areas, although CRP levels were lower and there were no differences in elevated CRP or AGP. CONCLUSIONS: The burden of anemia and iron deficiency in this population was substantial, and increased after adjusting for inflammation, suggesting potential to benefit from screening and interventions. REGISTRATION NUMBER: NCT04048330.

A randomized trial of iron- and zinc-biofortified pearl millet-based complementary feeding in children aged 12 to 18 months living in urban slums.

BACKGROUND & AIMS: Biofortification of staple crops with higher levels of micronutrients via traditional breeding methods is a sustainable strategy and can possibly complement fortification and other interventions to target micronutrient deficiencies in low resource settings, particularly among vulnerable populations such as children. We aimed to determine if iron- and zinc-biofortified pearl millet (FeZnPM, Dhanashakti, ICTP-8203Fe)-based complementary feeding improves nutritional status, including iron biomarkers and growth, in children living in urban slums of Mumbai. METHODS: We conducted a randomized controlled trial of FeZnPM among 223 children aged 12-18 months who were not severely anemic at baseline (hemoglobin ≥9.0 g/dL). Children were randomized to receive either FeZnPM or conventional non-biofortified pearl millet (CPM) daily for 9 months. Iron status (hemoglobin, serum ferritin), plasma zinc, and anthropometric indicators (length, weight, mid-upper arm circumference, triceps and subscapular skinfolds) were evaluated at enrollment and throughout the trial. World Health Organization (WHO) anthropometric z-scores were calculated using WHO growth standards. Primary outcomes were hemoglobin and serum ferritin concentrations, and growth, defined as WHO z-scores. An intent to treat approach was used for analyses. We used the Hodges-Lehmann-Sen test to assess the change in primary outcomes between baseline and the last visit and report corresponding 95% confidence intervals. RESULTS: At baseline, 67.7% of children were anemic (hemoglobin <11.0 g/dL) and 59.6% were iron deficient (serum ferritin <12.0 µg/L). FeZnPM did not significantly increase iron biomarkers or improve growth, compared to CPM. In subgroup analyses, FeZnPM improved hemoglobin concentrations in male children, and in children with iron deficiency or iron depletion (serum ferritin <25.0 µg/L) at baseline, relative to CPM. CONCLUSIONS: Daily consumption of FeZnPM-based complementary foods did not significantly impact iron and zinc status or growth in children living in Mumbai's urban slums. However, the intervention significantly improved hemoglobin concentrations among male children and among individuals who were iron-deficient or iron-depleted at baseline. TRIAL REGISTRATION: This trial is registered with Clinicaltrials.gov (ID: NCT02233764), and Clinical Trials Registry of India (ID: REF/2014/10/007731).

Vitamin B-12 and the Gastrointestinal Microbiome: A Systematic Review.

Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences. Emerging evidence suggests that vitamin B-12 may have an important role in other aspects of human health, including the composition and function of the gastrointestinal (gut) microbiome. Vitamin B-12 is synthesized and utilized by bacteria in the human gut microbiome and is required for over a dozen enzymes in bacteria, compared to only 2 in humans. However, the impact of vitamin B-12 on the gut microbiome has not been established. This systematic review was conducted to examine the evidence that links vitamin B-12 and the gut microbiome. A structured search strategy was used to identify in vitro, animal, and human studies that assessed vitamin B-12 status, dietary intake, or supplementation, and the gut microbiome using culture-independent techniques. A total of 22 studies (3 in vitro, 8 animal, 11 human observational studies) were included. Nineteen studies reported that vitamin B-12 intake, status, or supplementation was associated with gut microbiome outcomes, including beta-diversity, alpha-diversity, relative abundance of bacteria, functional capacity, or short-chain fatty acids (SCFA) production. Evidence suggests that vitamin B-12 may be associated with changes in bacterial abundance. While results from in vitro studies suggest that vitamin B-12 may increase alpha-diversity and shift gut microbiome composition (beta-diversity), findings from animal studies and observational human studies were heterogeneous. Based on evidence from in vitro and animal studies, microbiome outcomes may differ by cobalamin form and co-intervention. To date, few prospective observational studies and no randomized trials have been conducted to examine the effects of vitamin B-12 on the human gut microbiome. The impact of vitamin B-12 on the gut microbiome needs to be elucidated to inform screening and public health interventions.

Point-of-Care Quantification of Serum Alpha-Fetoprotein for Screening Birth Defects in Resource-Limited Settings: Proof-of-Concept Study.

BACKGROUND: Maternal serum alpha-fetoprotein (MSAFP) concentration typically increases during pregnancy and is routinely measured during the second trimester as a part of screening for fetal neural tube defects and Down syndrome. However, most pregnancy screening tests are not available in the settings they are needed the most. A mobile device-enabled technology based on MSAFP for screening birth defects could enable the rapid screening and triage of high-risk pregnancies, especially where maternal serum screening and fetal ultrasound scan facilities are not easily accessible. Shifting the approach from clinic- and laboratory-dependent care to a mobile platform based on our point-of-care approach will enable translation to resource-limited settings and the global health care market. OBJECTIVE: The objective of this study is to develop and perform proof-of-concept testing of a lateral flow immunoassay on a mobile platform for rapid, point-of-care quantification of serum alpha-fetoprotein (AFP) levels, from a drop of human serum, within a few minutes. METHODS: The development of the immunoassay involved the selection of commercially available antibodies and optimization of their concentrations by an iterative method to achieve the required detection limits. We compared the performance of our method with that of commercially obtained human serum samples, with known AFP concentrations quantified by the Abbott ARCHITECT chemiluminescent magnetic microparticle immunoassay (CMIA). RESULTS: We tested commercially obtained serum samples (N=20) with concentrations ranging from 2.2 to 446 ng/mL to compare the results of our point-of-care assay with results from the Abbott ARCHITECT CMIA. A correlation of 0.98 (P<.001) was observed on preliminary testing and comparison with the CMIA. The detection range of our point-of-care assay covers the range of maternal serum AFP levels observed during pregnancy. CONCLUSIONS: The preliminary test results from the AFP test on the mobile platform performed in this study represent a proof of concept that will pave the way for our future work focused on developing a mobile device-enabled quad-screen point-of-care testing with the potential to enable the screening of high-risk pregnancies in various settings. The AFP test on the mobile platform can be applied to enable screening for high-risk pregnancies, within a few minutes, at the point of care even in remote areas where maternal serum tests and fetal ultrasound scans are not easily accessible; assessment of whether clinical follow-up and diagnostic testing may be needed after a positive initial screening evaluation; and development of surveillance tools for birth defects.

Nutrition, Inflammation, and the Gut Microbiota among Outpatients with Active Tuberculosis Disease in India.

India has the highest rates of tuberculosis (TB) globally and a high prevalence of malnutrition; however, the interplay between host nutritional status, inflammation, and the gut microbiome in active tuberculosis disease (ATBD) is less well-studied. We examined differences in gut microbial composition and diversity based on undernutrition and inflammation status among outpatients with ATBD at the time of treatment initiation. During this exploratory cross-sectional study, outpatients (N = 32) with ATBD (confirmed by Xpert MTB/RIF) were enrolled in anti-TB treatment initiated at a hospital in rural southern India. The 16S rRNA sequencing was used to assess the composition of the gut microbiome. We assessed multiple markers of nutritional status, including micronutrient status concentrations (vitamin D [25(OH)D], vitamin B12, ferritin), anthropometry (body mass index, mid-upper arm circumference, and height), and C-reactive protein (CRP), as indicators of inflammation. We found that 25(OH)D was positively associated with the relative abundance of Oscillospira spp., a butyrate-producing genus linked with anti-inflammation effects, and that ferritin was positively associated with Proteobacteria taxa, which have been associated with worse inflammation in other studies. Finally, we found a greater abundance of inflammation-associated taxa from the Proteobacteria phylum and lower alpha-diversity indices among those who were underweight or who had low mid-upper arm circumference or short stature. In summary, we found differences in the gut microbiota composition and diversity among those with undernutrition compared with those with adequate nutrition status at the time of initiation of treatment among patients with ATBD in India. Clinical implications of these findings will need to be examined by larger longitudinal studies.

Nutritional Interventions and the Gut Microbiome in Children.

The gut microbiome plays an integral role in health and disease, and diet is a major driver of its composition, diversity, and functional capacity. Given the dynamic development of the gut microbiome in infants and children, it is critical to address two major questions: (a) Can diet modify the composition, diversity, or function of the gut microbiome, and (b) will such modification affect functional/clinical outcomes including immune function, cognitive development, and overall health? We synthesize the evidence on the effect of nutritional interventions on the gut microbiome in infants and children across 26 studies. Findings indicate the need to study older children, assess the whole intestinal tract, and harmonize methods and interpretation of findings, which are critical for informing meaningful clinical and public health practice. These findings are relevant for precision health, may help identify windows of opportunity for intervention, and may inform the design and delivery of such interventions.

Anemia and Vitamin B-12 and Folate Status in Women of Reproductive Age in Southern India: Estimating Population-Based Risk of Neural Tube Defects.

BACKGROUND: Women of reproductive age (WRA) are a high-risk population for anemia and micronutrient deficiencies. However, there are few representative population-level data from India, which could help inform evidence-based recommendations and policy. OBJECTIVE: To conduct a population-based biomarker survey of anemia and vitamin B-12 and folate status in WRA as part of a periconceptional surveillance program in southern India. METHODS: Participants were WRA (15-40 y) who were not pregnant or lactating. Whole blood (n = 979) was analyzed for hemoglobin via a Coulter counter (Coulter HMX). Plasma, serum, and RBCs were processed and stored at -80°C or less until batch analysis. Vitamin B-12 concentrations were measured via chemiluminescence; RBC and serum folate concentrations were evaluated via microbiological assay. Anemia and severe anemia were defined as hemoglobin <12.0 g/dL and <8.0 g/dL, respectively. Vitamin B-12 deficiency and insufficiency were defined as total vitamin B-12 <148 pmol/L and <221 pmol/L, respectively. Folate deficiency and insufficiency were defined as RBC folate <305 nmol/L and <748 nmol/L. A previously developed Bayesian model was used to predict neural tube defect (NTD) prevalence per 10,000 births. RESULTS: A total of 41.5% of WRA had anemia and 3.0% had severe anemia. A total of 48.3% of WRA had vitamin B-12 deficiency and 74.3% had vitamin B-12 insufficiency. The prevalence of RBC folate deficiency was 7.6%, and 79.3% of WRA had RBC folate <748 nmol/L, the threshold for optimal NTD prevention. Predicted NTD prevalence per 10,000 births based on RBC folate concentrations was 20.6 (95% uncertainty interval: 16.5-25.5). CONCLUSIONS: The substantial burden of anemia, vitamin B-12 deficiency, and RBC folate insufficiency in WRA in this setting suggests an opportunity for anemia and birth defects prevention. Findings will directly inform the development of a randomized trial for anemia and birth defects prevention in southern India.This study was registered at clinicaltrials.gov as NCT04048330.

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.

Maternal vitamin B12 deficiency and perinatal outcomes in southern India.

BACKGROUND: Vitamin B12 deficiency during pregnancy has been associated with adverse maternal and infant health outcomes. Few prospective studies have investigated vitamin B12 status early in pregnancy, and its links to infant vitamin B12 status, particularly in India where the burden of vitamin B12 deficiency is estimated to be the highest globally. The objective of this study was to examine the associations of maternal vitamin B12 biomarkers with neonatal vitamin B12 status. METHODS: Pregnant women (~12 weeks' gestation) were enrolled in a perinatal cohort study in Bangalore, India. Total vitamin B12, methylmalonic acid (MMA), and homocysteine concentrations were evaluated in maternal samples at enrollment and in neonates at birth using cord blood. Linear and binomial regression models were used to evaluate the associations of maternal vitamin B12 biomarkers with neonatal vitamin B12 status and perinatal outcomes. RESULTS: A total of 63.2% of women had vitamin B12 deficiency (<148 pmol/L), 87.2% had vitamin B12 insufficiency (<221 pmol/L), and 47.3% had impaired vitamin B12 status (vitamin B12<148 pmol/L and MMA>0.26µmol/L) at enrollment; 40.8% of neonates had vitamin B12 deficiency, 65.6% were insufficiency, and 38.1% had impaired vitamin B12 status at birth. Higher maternal vitamin B12 concentrations at enrollment were associated with increased neonatal vitamin B12 concentrations (ß(SE): 0.40 (0.05); p<0.0001) and lower risk of neonatal vitamin B12 deficiency (Risk Ratio [RR]: 0.53; 95% CI: [0.43, 0.65]; p<0.0001). Maternal vitamin B12 deficiency (RR: 1.97 [1.43, 2.71]; p<0.001), insufficiency (RR: 2.18 [1.23, 3.85]; p = 0.007), and impaired vitamin B12 status (RR: 1.49 [1.13, 1.97]; p = 0.005) predicted a two-fold increase in the risk of neonatal vitamin B12 deficiency at birth. CONCLUSIONS: The prevalence of vitamin B12 deficiency was high early in pregnancy and predicted neonatal vitamin B12 status. Future research is needed to determine the role of vitamin B12 in the development of pregnancy and infant outcomes, and to inform screening and interventions to improve maternal and child health.

Update on the Transmission of Zika Virus Through Breast Milk and Breastfeeding: A Systematic Review of the Evidence.

We systematically searched regional and international databases and screened 1658 non-duplicate records describing women with suspected or confirmed ZIKV infection, intending to breastfeed or give breast milk to an infant to examine the potential of mother-to-child transmission of Zika virus (ZIKV) through breast milk or breastfeeding-related practices. Fourteen studies met our inclusion criteria and inform this analysis. These studies reported on 97 mother-children pairs who provided breast milk for ZIKV assessment. Seventeen breast milk samples from different women were found positive for ZIKV via RT-PCR, and ZIKV replication was found in cell cultures from five out of seven breast milk samples from different women. Only three out of six infants who had ZIKV infection were breastfed, no evidence of clinical complications was found to be associated with ZIKV RNA in breast milk. This review updates our previous report by including 12 new articles, in which we found no evidence of ZIKV mother-to-child transmission through breast milk intake or breastfeeding. As the certainty of the present evidence is low, additional studies are still warranted to determine if ZIKV can be transmitted through breastfeeding.

Transmission of SARS-CoV-2 through breast milk and breastfeeding: a living systematic review.

The pandemic of coronavirus disease 2019 (COVID-19) is caused by infection with a novel coronavirus strain, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, there is limited information on potential transmission of the infection from mother to child, particularly through breast milk and breastfeeding. Here, we provide a living systematic review to capture information that might necessitate changes in the guidance on breast milk and breastfeeding given the uncertainty in this area. Our search retrieved 19,414 total records; 605 were considered for full-text eligibility and no ongoing trials were identified. Our review includes 340 records, 37 with breast milk samples and 303 without. The 37 articles with analyzed breast milk samples reported on 77 mothers who were breastfeeding their children; among them, 19 of 77 children were confirmed COVID-19 cases based on RT-PCR assays, including 14 neonates and five older infants. Nine of the 68 analyzed breast milk samples from mothers with COVID-19 were positive for SARS-CoV-2 RNA; of the exposed infants, four were positive and two were negative for COVID-19. Currently, there is no evidence of SARS-CoV-2 transmission through breast milk. Studies are needed with longer follow-up periods that collect data on infant feeding practices and on viral presence in breast milk.

Presence of Ebola virus in breast milk and risk of mother-to-child transmission: synthesis of evidence.

To help inform global guidelines on infant feeding, this systematic review synthesizes evidence related to the presence of the Ebola virus (EBOV) in breast milk and its potential risk of viral transmission to the infant when breastfeeding. We relied on a comprehensive search strategy to identify studies including women with suspected, probable, or confirmed EBOV infection, intending to breastfeed or give breast milk to an infant. Our search identified 10,454 records, and after deduplication and screening, we assessed 148 full texts. We included eight studies reporting on 10 breastfeeding mothers and their children (one mother with twins), who provided breast milk samples for assessment. EBOV was detected via RT-PCR or viral culture in seven out of ten breast milk samples. Four out of the five-breastfed infants with EBOV-positive breast milk were found positive for EBOV infection, and all of these EBOV-positive infants died. Since previous reports have detected EBOV in tears, saliva, sweat, and contaminated surfaces, with the current evidence, it is not possible to conclude with certainty that breast milk was the main route of EBOV transmission.

Periconceptional surveillance for prevention of anaemia and birth defects in Southern India: protocol for a biomarker survey in women of reproductive age.

INTRODUCTION: Women of reproductive age (WRA) are a high-risk population for anaemia and micronutrient deficiencies. Evidence supports the role of periconceptional nutrition in the development of adverse pregnancy complications. However, in India, there are limited population-based data to guide evidence-based recommendations and priority setting. The objective of this study is to conduct a population-based biomarker survey of anaemia and vitamin B12 and folate status in WRA as part of a periconceptional surveillance programme in Southern India. METHODS: WRA (15-40 years) who are not pregnant or lactating and reside within 50 km2 of our community research site in Southern India will be screened and invited to participate in the biomarker survey at our research facility at Arogyavaram Medical Centre. After informed consent/assent, structured interviews will be conducted by trained nurse enumerators to collect sociodemographic, dietary, anthropometry, health and reproductive history data. Venous blood samples will be collected at enrolment; whole blood will be analysed for haemoglobin. Plasma, serum and red blood cells (RBCs) will be processed and stored <-80°C until batch analysis. Vitamin B12 concentrations will be measured via chemiluminescence, and RBC and serum folate concentrations will be evaluated using the World Health Organisation (WHO)-recommended microbiological assay at our laboratory in Bangalore. A WHO surveillance system will also be established to determine the baseline prevalence of birth defects in this setting. ETHICS AND DISSEMINATION: This study has obtained clearance from the Health Ministry Screening Committee of the Indian Council of Medical Research. The study protocol was reviewed and approved by the Institutional Review Board at Cornell University and the Institutional Ethics Committees at Arogyavaram Medical Centre and St. John's Research Institute. Findings from this biomarker survey will establish the burden of anaemia and micronutrient deficiencies in WRA and directly inform a randomised trial for anaemia and birth defects prevention in Southern India. The results of this study will be disseminated at international research conferences and as published articles in peer-reviewed journals. TRIAL REGISTRATION NUMBERS: Clinical trials registration number NCT04048330, NCT03853304 and Clinical Trials Registry of India (CTRI) registration number REF/2019/03/024479.