BACKGROUND:The protein requirement of clinically normal but chronically undernourished (stunted) children is unknown. Stressors, similar to intestinal parasites, in poor environments may increase this requirement. The current protein requirement, which is based on factorial methods in healthy, well-nourished children, may be incorrect. OBJECTIVES:This study aimed to determine the effect of intestinal parasites on the protein requirement of chronically undernourished school-age South Indian children, by the indicator amino acid oxidation technique. METHODS:Eighteen undernourished school-age South Indian children (aged 6-11 y) were studied before and after treatment for the confirmed presence of intestinal parasites. They were randomly assigned to receive a low or high protein intake from a range of 8 protein concentrations (0.24-2.38 g/kg/d), provided as an egg protein-based amino acid mixture in an isocaloric experimental diet providing energy at 1.7 times the measured resting energy expenditure. A constant and generous intake of the indicator amino acid (phenylalanine and its metabolite tyrosine) was ensured across all intake amounts. A 2-phase linear regression crossover analysis of the pattern of 13C-phenylalanine oxidation across the protein intake amounts before and after treatment identified a minimal oxidation breakpoint that represented the mean protein requirement. RESULTS:The mean [95% confidence interval (CI)] protein requirement of undernourished school-age South Indian children with intestinal parasites was determined to be 1.25 (95% CI: 1.0, 1.5) g/kg/d. After antiparasite treatment, the requirement was not different at 1.43 (95% CI: 1.1, 1.8) g/kg/d. CONCLUSIONS:The presence of intestinal parasites does not increase the protein requirement of undernourished Indian children. However, the current mean [+2 standard deviation (SD)] protein requirement of 0.76 (SD: 0.95) g/kg/d might be inadequate for this group.

Introduction Environmental enteropathy (EE) is a syndrome affecting the gut characterised by villus blunting, reduced nutrient absorption and microbial translocation in children and adults experiencing a high burden of enteric infection due to inadequate access to clean water and sanitation. Methods and analysis We will conduct coordinated randomised controlled trials in six countries to determine if supplementation with indispensable amino acids (IAAs) can improve intestinal barrier dysfunction in six geographically diverse populations of 18–36 months old children with stunting or severe stunting. All trials will measure the same primary outcomes while secondary outcomes will be measured on a per-trial basis using standardised protocols across the project. The primary endpoint will be change in gut permeability as assessed by the lactulose/rhamnose ratio. Secondary endpoints include changes in amino acid and carbohydrate absorption using novel, isotope tracer tests. Other prespecified outcome measures include changes in EE biomarkers and child weight. IAA supplementation will be given daily for 28 days and evaluation of the major endpoints will be at baseline and after 28 days of supplementation. Ethics and dissemination Ethical approval will be obtained from the Research Ethics Committee at each participating site. Caregivers will provide written informed consent for each participant. Findings will be disseminated through peer-reviewed journals, conference presentations and face-to-face meetings with participant caregivers. Trial registration number CTRI: CTRI/2024/06/069187 (India); ClinicalTrials.gov ( NCT06617130 , Malawi; NCT06676215 , Philippines and NCT07256028 , Morocco); Ongoing (Zambia); Ongoing (Morocco); PACTR: (PACTR202311714091884, Ghana).

Human milk from healthy, well-nourished women is the optimal nutrition for infants and young children, and exclusive breastfeeding is recommended for the first 6 mo. In the context of poor diets, the quality of milk may be compromised, and understanding the relationships between maternal diet, human milk nutrient concentrations, and milk intakes in young infants is important for guiding policy. The Mothers, Infants, and Lactation Quality (MILQ) study collected human milk samples from 1 to 8.5 mo of lactation in 558 well-nourished but unsupplemented women in Bangladesh, Brazil, Denmark, and The Gambia. Milk intakes were measured at 3 visits postnatally (1-3.49 mo, 3.5-5.99 mo, and 6.0-8.5 mo). Milk intakes were assessed in 3 sites (Bangladesh, Brazil, and The Gambia) using the stable isotope dilution dose-to-mother method. In Denmark, intakes were measured by test weighing, and volume data were corrected by a factor of 1.05 to account for insensible water losses. The mean ± standard deviation human milk intake across sites and time points was 781 ± 193 g/d. Milk intakes were comparable among sites early in lactation, but as intakes decreased across lactation, between-site differences emerged as nonmilk feeds were introduced. Exclusively breastfed infants consumed greater volumes of milk each day than mixed-fed infants. When expressed against infant body weight, a gradual decrease in milk intake was observed across lactation. Milk nutrient concentrations were largely unrelated to daily milk intakes. Therefore, correlations between milk nutrient concentrations and total daily intake of nutrients were mostly positive and strong. Mean milk intake in the MILQ study was consistent with previously published global data, although variability was observed across lactation and between contexts. Infants consuming greater milk volumes had greater daily intakes of milk nutrients. The implications for infant status and recommended nutrient intakes require further investigation.

Background: Childhood malnutrition, both undernutrition and overnutrition, is a major health concern in many low- and middle-income countries (LMICs). Efforts to reduce early undernutrition could also lead to obesity. In an earlier study, we reported the successful impact of a package of preconception, pregnancy, postnatal, and/or early childhood interventions (health, nutrition, psychosocial support, and water, sanitation, and hygiene) delivered in the first 1000 d, on reducing stunting in low-to-middle-income populations, in comparison with routine care. However, the impact of these interventions on early body composition and subsequent overweight is not known. Objectives: The objective of this study was to estimate the effect of a package of interventions directed at preventing stunting in the first 1000 don body composition at 1 mo and childhood overweight and/or obesity at 24 mo of age. Methods: Infant body composition was measured by deuterium dilution at 1 mo of age, along with the prevalence of childhood overweight and/or obesity at 24 mo, defined by a body mass index-for-Age Z (BMIz) score >& thorn;2 standard deviation. Results: Children in the preconception, pregnancy, and early childhood intervention group and those in the pregnancy and early childhood intervention group had higher body mass index z scores than those in routine care. However, the prevalence of overweight and/or obesity was low (ranging from 0.0 to 1.3%). Pregnancy interventions significantly increased neonatal fat-free mass (mean difference 0.1 kg, 95% confidence interval [CI]: 0.01, 0.2). However, there was no significant change in fat mass. Conclusions: Comprehensive interventions from preconception to early childhood improve linear growth but do not result in overweight and/or obesity at 24 mo. With better resultant linear and ponderal growth, they converge with the World Health Organization's "double-duty actions for nutrition" for LMIC settings, where childhood overweight and/or obesity is a growing concern.

BackgroundTo assess utility of novel biomarkers in diagnosing children with clinical cobalamin deficiency. Current practice uses total vitamin B12 levels to confirm diagnosis, which lacks sensitivity when used in isolation.MethodsBetween November 2020 and September 2022, a prospective cross-sectional study was carried out in a tertiary teaching hospital. Children between 1 month and 18 years with clinical symptoms/at-risk of developing B12 deficiency were included. Relevant clinical and laboratory information (including total B12 and biomarker levels) was documented. Sensitivity and specificity of individual biomarkers were assessed using 4cB12, an indicator of functional B12 status. Version 4.2.1 of R language was used for statistical analysis.ResultsAnalysis was performed on 67 children. Anorexia, fatigue and behavioural abnormalities were among the leading clinical characteristics. 49% children had peripheral smear (PS) suggestive of cobalamin deficiency, and 43% had low total B12 levels. Among biomarkers, 85% children had low holotranscobalamin (HoloTC), and 73% and 55% had high methylmalonic acid (MMA) and elevated homocysteine (Hcy) levels, respectively. Sensitivity of total B12 was 51%, HoloTC 87%, MMA 83% and Hcy 64%. Combination of low HoloTC, macrocytosis and abnormal PS had 94% sensitivity while HoloTC with mean corpuscular volume (MCV) alone was 88% sensitive in detecting cobalamin deficiency.ConclusionLow total B12 levels lack sensitivity to diagnose cobalamin deficiency. Although combination of low HoloTC with abnormal smear and macrocytosis was found to have better sensitivity, reporting an abnormal smear is time consuming and requires skilled personnel. Combination of low HoloTC with macrocytosis has good sensitivity and can be considered a better screening tool for detecting B12 deficiency.

BACKGROUND:In low- and middle-income countries, legumes are commonly used as a high-quality protein source in complementary foods. However, the digestibility of legume protein in infants might be low because of the immaturity of the digestive system at that age. OBJECTIVES:The aim of this study was to measure the true indispensable amino acid (IAA) digestibility of mung bean protein in infants aged 10-12 mo. METHODS:This was a cross-sectional study in which the IAA digestibility of intrinsically 2H-labeled mung bean protein was measured against U-[13C]-spirulina protein as a reference in 6 apparently healthy infants using the dual stable isotope technique. The IAA digestibility of the reference protein, U-[13C]-spirulina, was also measured in an additional 3 infants against a 2H-free amino acid mixture. RESULTS:The mean true IAA digestibility of mung bean protein and that of spirulina protein was 83.6% ± 23.0% and 103.5% ± 33.0%, respectively. These values in infants were higher than those determined earlier in adults (83.6% compared with 63.2% and 103.5% compared with 85.2% for mung bean and spirulina protein, respectively). In mung bean, digestibility ranged from 59.4% ± 11.6% (valine) to 126.5% ± 20.8% (isoleucine) and in spirulina from 46.9% ± 3.3% (valine) to 148.0% ± 17.7% (isoleucine). The digestible indispensable amino acid score (DIAAS) for mung bean protein at this age was 50%. CONCLUSIONS:Infants have a high mean IAA digestibility for mung bean protein, although the generalizability of this finding needs to be confirmed. The estimated DIAAS remains low at 50%. In plant-based complementary foods, a ratio of 1:2 of a legume-cereal mix is required to meet protein requirement in infants at this age. This trial was registered at the Clinical Trials Registry of India as CTRI/2020/09/027639.

It is not clear whether impaired amino acid (AA) absorption occurs in adults with environmental enteropathy (EE). Therefore, we set out to determine the association between intestinal 13 C 6 15 N-allo-isoleucine absorption (reflecting neutral AA transport) and lactulose–rhamnose ratio (LRR, reflecting permeability) in healthy adult volunteers (aged 18–35 years; N = 6) from India, and in those with biopsy-confirmed EE ( N = 20) from Zambia. A 3-hour oral bolus protocol using 13 C 6 15 N-allo-isoleucine (M), co-administered with lactulose and rhamnose sugars, was used to estimate AA absorption (as M area under the curve [AUC]) and LRR. Additionally, duodenal biopsies were collected from participants in Zambia. There was no association between allo-isoleucine absorption and LRR (separately by site or combined), but there was a significant positive correlation with crypt depth ( N = 16; Spearman’s rank correlation coefficient [ r s ] = 0.666; P -value = 0.005) in the Zambian participants. However, on exploratory analysis, the peak concentration (within first hour post-dose) of allo-isoleucine was significantly and positively correlated with the percentage of rhamnose dose recovered (%R; N = 24, participants combined; r s = 0.434; P -value = 0.034), and with crypt depth ( N = 16; r s = 0.713; P -value = 0.002). There were differences noted between the two sites: Zambian participants had a significantly lower median [range]%R (3.0 [1.0–4.6] versus 6.1% [3.2–7.7]) and allo-isoleucine (M + [M-1] AUC, 1.62 [0.73–5.44] versus 4.41 [3.69–5.37] µM*h/L) compared with those from India. In conclusion, allo-isoleucine absorption correlated with %R (reflecting intestinal absorptive surface area) but not LRR.

Background and objective: Valid and cost-effective approaches are essential to assess physical activity and sedentary behaviors in individuals of all ages. This study aimed to validate a physical activity recall questionnaire (PAR-Q) and a physical activity log against the doubly labelled water (DLW) technique in 11-13-year-old Sri Lankan children. Method: Total energy expenditure (TEE) was determined using the criterion DLW technique (TEEDLW) and physical activity energy expenditure (PAEEDLW) was estimated. Subsequently, physical activity assessment methods were validated in a group of children (n=96). PAR-Q was adapted from the adolescent physical activity questionnaire and the physical activity log from the Bouchard activity diary. The youth physical activity compendium was used to calculate PAEE from both PAR-Q (PAEEPAR-Q) and activity log (PAEEPALog). Statistical analysis included Spearman’s correlation coefficient and Bland-Altman analyses. Results: Mean age of the study sample was 12.0 ± 0.8 years where the greater proportion were males (51.9%, n=41). PAEEPAR-Q and PAEEPALog were significantly correlated with the PAEEDLW (r=0.63 and r=0.49, p < 0.05). PAR-Q and activity log underestimated PAEE by 304.2 ± 1223.8 kJ/day and 375.3 ± 1087.4 kJ/day, respectively. Using Bland-Altman analysis, the majority of data points were within the limits of agreement in both PAR-Q and activity log. Conclusion: PAR-Q is a valid tool for predicting PAEE in Sri Lankan children whereas the physical activity log was not. Researchers and practitioners can confidently use the PAR-Q to assess physical activity in this population, with potential applications in various research and intervention settings.

BACKGROUND:Complementary feeding is vital for meeting infants' nutritional needs. In low-to-middle-income countries (LMICs), limited dietary diversity often leads to inadequate protein intake, contributing to growth faltering. Conversely, excessive intake may increase risk of early-life obesity, but evidence on the optimal balance remains limited. OBJECTIVES:This study aimed to measure the effects of micronutrient-fortified, isocaloric high- and moderate-protein supplementation in infants aged 6-12 mo on overweight and/or obesity [body mass index (BMI)-for-age z-scores (BMIz) >2 SD] and body composition, that is, fat mass (FM), fat-free mass (FFM) and percentage FM (% FM) at 12 mo, and to evaluate obesity-related outcomes at 24 mo, compared with a no supplementation group. METHODS:This analysis is a secondary objective of a 3-arm randomized controlled trial in Delhi, India. Six-mo-old infants were allocated (1:1:1) to receive 1 daily packet of isocaloric high-protein supplementation (5.6 g), moderate-protein supplementation (2.5 g), or no supplementation. The isocaloric supplements provided 30% protein from milk, 30%-45% energy from fats, and 80%-100% recommended dietary allowance of key micronutrients. Comparisons were made between the no supplementation group and each supplementation group. RESULTS:Obesity prevalence was low at 12 mo (0.8% moderate-protein, 0.4% high-protein, 0.6% no supplementation; P = 0.65, no significant difference between groups) and at 24 mo (0.6% in supplemented groups, 0.2% no supplementation; P = 0.56, not significant). High-protein supplementation led to a modest but statistically significant increase in BMIz at 12 mo [adjusted mean difference: 0.12; 95% confidence interval (CI): 0.02, 0.22] compared with the no supplementation group, but not at 24 mo (-0.02; 95% CI: -0.12, 0.09). No significant differences were observed in FM, FFM, or %FM at 12 mo. CONCLUSIONS:High-protein supplementation from 6 to 12 mo did not increase fat accretion or obesity risk at 24 mo. Nutritional interventions in LMICs should prioritize both protein quality and overall dietary balance to simultaneously prevent undernutrition and excess weight gain. This study was registered at http://ctri.nic.in/Clinicaltrials/login.php as CTRI/2018/04/012932 for the main trial and CTRI/2019/03/018238 for the follow-up study.

Background: It is plausible that one of the key biological pathways through which kangaroo mother care (KMC) improves health outcomes in low birth weight (LBW) infants is by enhancing human milk intake and quality. This hypothesis needs to be tested. Objectives: This study aims to estimate the effect of promotion and support of KMC in LBW infants compared with control during the neonatal period on human milk intake and human milk components. Methods: We randomly assigned 550 LBW infants (1500-2250 g) to the intervention arm with promotion of and support for continuous skin-to-skin contact and exclusive breastfeeding through home visits or to no such intervention (control) during the neonatal period. All infants received routine home-based postnatal care visits. We estimated human milk intake by the infant over a 14-d period using the deuterium dilution technique and measured the concentration of carbohydrate, protein and amino acids, fat, lactoferrin, and secretory immunoglobulin A (sIgA) in human milk of a subsample of 250 mothers. Results: The mean infant human milk intake was 331 f 144 g/d or 142 f 57 g/kg/d in the control arm and 368 f 135 g/d or 154 f 50 g/kg/d in the intervention arm participants, yielding a mean difference of 37 [95% confidence interval (CI): 12, 63] g/d or 12 (95% CI: 2, 22) g/kg/d. The mean concentration of carbohydrate in human milk in the intervention arm was 51.2 f 6.1 g/L against 50 f 6.8 g/L in the control arm. The corresponding values for protein were 15.0 f 2.9 g/L and 16.3 f 4.6 g/L, respectively. We did not find any substantial differences in the concentration of amino acids, fat, lactoferrin, or sIgA between the study arms. Conclusions: Our findings show that KMC is associated with a substantially higher human milk intake in LBW infants during the neonatal period. There was no evidence of any effect of KMC on the concentration of several human milk components. This trial was registered at Clinical Trials Registry-India as CTRI/2017/04/008430.

BACKGROUND:Inadequate protein intake in early life is associated with both growth retardation and a higher risk of metabolic syndrome in later life. OBJECTIVE:This study aimed to evaluate the effects on energy metabolism of protein or indispensable amino acids (IAAs; lysine, threonine, and methionine) supplementation following a deficiency in growing rats. METHODS:Sixty Wistar Han male rats were fed a control (20% protein by energy content), protein-deficient (P5, 5% protein by energy content), or lysine, threonine, or methionine-deficient diet (L25, T25, and M25, respectively; 25% of the IAA requirement) for 3 wk and thereafter were supplemented for 3 wk with the deficient IAA or protein to reach 100% of the IAA (T100, L100, and M100, respectively) or protein requirement (P20). Body weight (BW) and relative food intake (rFI) were measured daily. Body composition, nasoanal length (NAL), energy expenditure, and plasma fibroblast growth factor 21 were measured at the end of the deficiency and supplementation phases. Data were analyzed using 1-way or mixed-model ANOVA and Bonferonni tests for multiple comparisons. RESULTS:All deficient diets induced growth retardation [lower BW, lean body mass (LBM), and NAL], with threonine deficiency having the most severe effect (60% lower BW of control; P < 0.001). Supplementation induced a resumption of growth, but BW and LBM remained lower (15%-35% for BW and 69%- 84% for LBM of control; P < 0.001). Despite increased rFI, no excess adiposity was observed postsupplementation in P20 and T100 groups, likely due to increased energy expenditure (P < 0.001). In L100 and M100 groups, rFI increased (by 35% and 30%, respectively; P < 0.001) without a corresponding rise in energy expenditure. Fibroblast growth factor 21 was inversely associated with the protein and IAA statuses during both deficiency and supplementation (P < 0.001). CONCLUSIONS:These findings highlight the distinct roles of individual IAAs in growth and metabolic recovery and suggest that targeted IAA supplementation may improve nutritional interventions.

Diagnosis of vitamin B12 (B12) deficiency is hampered by the low specificity cut-offs of blood-based biomarkers, like serum B12 and holo-transcobalamin (HoloTc), or B12-associated metabolites like methylmalonic acid (MMA) and homocysteine (Hcy) concentrations, or their combinations computed as combined B12 (cB12). We assessed B12 deficiency through non-invasive [13C]-propionate oxidation breath test to derive functional cut-off and tested its sensitivity in response to acute change in B12 status in low B12 adult male participants by parenterally administering 3 mg hydroxocobalamin and profiling through untargeted and targeted B12 related metabolites. The functional deficiency cut-off, based on a breakpoint analysis of [13C]-propionate oxidation with B12 concentrations, was 144 pmol/L [95% CI 106.4-182.4, p = 0.02] for B12 deficiency. Untargeted metabolomic analyses revealed potential functional B12 metabolites that are known to be associated with mitochondrial function, oxidative stress, lipids, bile acids and 1-carbon metabolism. Parenteral B12 treatment increased [13C]-propionate oxidation (14.9%, range 1.1 to 66.9) significantly and was also associated with significant alterations (p < 0.05) in B12, HoloTc, MMA, Hcy concentrations, cB12, and associated functional metabolites like propionylcarnitine (C3), its ratio to acetylcarnitine (C3/C2) and palmitoylcarnitine (C3/C16). This study explores the clinical utility of propionate breath test to define functional B12 deficiency and associated metabolites through omics-based approach.This study was registered in Clinical Trials Registry of India (CTRI) with the registration number CTRI/2018/04/012957 (registered on 03/04/2018), available from https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=MjQwNDc=&Enc=&userName .

BACKGROUND:Vitamin B12 deficiency is a prevalent health concern that can lead to hematological and neurological disorders. Despite adequate intake, vitamin B12 deficiency/insufficiency can arise due to interindividual differences in absorption and metabolism influenced by genetic factors, gastrointestinal health, and medications. Although previous studies have explored the genetic basis of circulating vitamin B12 concentration, they have not been validated using precise, stable, isotope-based measurements of vitamin B12 bioavailability. OBJECTIVES:To measure the plasma bioavailability of an oral dose of [13C]-labeled vitamin B12 (cyanocobalamin) using 2-compartment pharmacokinetic modeling and examine its associations with genetic variants in key genes involved in vitamin B12-related pathways. METHODS:In a cohort of 104 young healthy Indian adults, functional vitamin B12 markers including total vitamin B12 and holotranscobalamin were measured using chemiluminescence immunoassays. Bioavailability was estimated by nonlinear mixed effects modeling of plasma vitamin B12 time-concentration profiles using a modified 2-compartment model. Genetic associations were analyzed, and polygenic risk scores (PRSs) were computed. RESULTS:The mean measured vitamin B12 bioavailability was 52% ± 16%, demonstrating significant 4.4-fold variability. A total of 85 single nucleotide polymorphism (SNPs) in/near 14 genes were significantly associated with vitamin B12 bioavailability, including 5 previously reported SNPs associated with vitamin B12-related traits and 80 novel variants from known vitamin B12 pathway genes. Bioavailability-PRS explained 72% (95% CI: 60%, 81%) of the variance in vitamin B12 bioavailability in the same cohort and 55% in a 3-fold cross-validation test. At the first quartile threshold, the PRS identified individuals requiring supplementation with a positive predictive value of 0.32. CONCLUSIONS:These findings provide insights into the genetic determinants of vitamin B12 absorption and homeostasis, emphasizing the potential of using genetic markers to personalize nutritional strategies. This is critical for identifying subgroups susceptible to vitamin B12 deficiency despite adequate intake, highlighting the need for precision nutrition led by functional measurements in specific populations. This trial was registered in Clinical Trials Registry of India (CTRI) as CTRI/2020/11/029108.

The World Health Organization recommends exclusive breastfeeding for the first 6 mo of life and continued breastfeeding for 2 y or beyond. However, limited reliable, representative data on nutrient concentrations in milk from well-nourished mothers are available. Furthermore, there is a lack of data integrating human milk nutrient concentrations with the volume of milk transferred to infants during progressive stages of lactation. Accurate quantification of nutrient concentrations and milk volume is essential for setting macro- and micronutrient intake recommendations for infants and women's additional requirements for lactation. This first article in a series of 7 in this Supplement describes the Mothers, Infants, and Lactation Quality (MILQ) study conducted at sites in Bangladesh, Brazil, Denmark, and The Gambia. The MILQ study measured human milk nutrient concentrations and quantified milk volume throughout the first 8.5 mo of lactation. Validated analytical methodologies were used for nutrient quantification. The stable isotope dilution dose-to-mother method was used for milk volume measurement. A total of 1242 mother-infant dyads participated in the MILQ study. Milk volumes, milk nutrient concentrations, percentile curves, and total nutrient intakes (concentration times milk volume at each time point) are presented in the series of articles in this supplement. Comparisons are made between values in the MILQ study and those used by the Institute of Medicine (now renamed the National Academy of Medicine) to set nutrient intake recommendations for infants and lactating women, and with other selected studies. Data from the MILQ study provide a valuable resource for updating existing nutrient intake recommendations, evaluating and improving infant nutrition strategies, and assessing interventions to optimize maternal and infant nutritional status and health.

Background: Environmental enteropathy' (EE) is common among children who are highly exposed to enteric pathogens in low-resource settings. We optimized and validated a stable isotope-based breath test of intestinal sucrase activity (13C-SBT) as a noninvasive test of carbohydrate digestion and metabolism. Objectives: The primary objective of this study was to assess the relationship between the 13 C-SBT and the lactulose/rhamnose ratio (LR) and growth in children. Secondary objectives were to assess the relationship between the 13 C-SBT and additional biomarkers of EE. We also characterized the relationship between the 13 C-SBT and child sex and dietary diversity, as well as household socio-economic status and food security. Methods: In this cross-sectional study, 12-to-15-mo-old children were recruited in Bangladesh, India, Kenya, and Peru. Children were assessed with a 4-h 13 C-SBT and a 90-min LR test. Plasma was collected to determine the citrulline and kynurenine/tryptophan ratio. Length and weight were measured, and other variables were assessed through questionnaires. For a subset of children, anthropometry was re-measured after 3 mo. Linear regression was used to examine associations corresponding to each objective. Results: Three sites generated 13 C-SBT breath curves that enabled pooled analysis. Differences in 13 C-SBT breath curves, LR ratios, and other EE biomarkers were observed between sites. No associations were observed for 13 C-SBT summary measures and LR or child growth [e.g., the association between LR and cumulative percent dose recovered at 90 min: - 0.39; 95% confidence interval (CI): - 1.79, 0.70]. Length-for-age and weight-for-age were positively associated with the time to 50% of dose recovered (0.05; 95% CI: 0.01, 0.09, and 0.05; 95% CI: 0.02, 0.07, respectively), and dietary diversity was associated with time at which 50% of the dose recovered by 240 min is recovered and cumulative percent dose recovered at 90 min (-0.10; 95% CI: - 0.18, - 0.02 and 2.67; 95% CI: 0.47, 4.88, respectively). Conclusions: In children at risk of EE, there were no associations between the 13 C-SBT, LR, or other EE biomarkers encompassing different pathophysiological domains of EE.

Abstract Objectives: To assess the impact of nutritional and multiple-micronutrient supplementation to lactating mothers on the micronutrient status of mother–infant dyad at 6 months of age postnatally. Design: This study was a trial that aimed to investigate the impact of maternal nutritional supplementation on infant growth. A secondary objective was to assess the effect on the micronutrient status of mother–infant pairs. The intervention group mothers received snacks with 600 kcal energy, 20 g protein and daily micronutrient tablets. Setting: Blood samples were collected from both mothers and infants at 6 months. Participants: The participants in this study were mother–infant pairs. The micronutrient status of these pairs was assessed through blood samples, focusing on vitamins A, D, B12, ferritin, Zn and folate. Results: Micronutrient analysis of serum samples from 600 mother–infant pairs showed that mothers in the intervention group had higher levels of serum ferritin (mean difference (MD) 14·7 ng/ml), retinol (MD 0·6 μmol/l), folate (MD 3·3 ng/ml) and vitamin D (1·03 ng/ml) at 6 months postpartum. Additionally, the supplementation was associated with a higher mean ± sd of serum ferritin (MD 8·9 ng/ml) and vitamin A (MD 0·2 μmol/l) levels in infants at 6 months. Conclusions: The study found that supplementing maternal nutrition with additional dietary and micronutrient intakes during lactation improved maternal micronutrient status and slightly increased ferritin and vitamin A levels in infants at 6 months. The findings highlight the importance of nutritional interventions for improving the micronutrient health of mother–infant pairs, with significant public health implications. Trial registered at www.clinicaltrials.gov (CTRI/2018/04/013095).

The changing global climate brings a gradual yet constant and adverse shift in crop production. Grain crop plants, particularly cereals and legumes, respond varyingly to adverse climate, including reduction in grain yield and changes to their nutrient densities. An understanding of specific changes to crop systems under differing climatic conditions can help in planning diets to meet human nutrient sufficiency. Grain protein content is also affected by adverse environmental factors. Deficits in protein yield, linked to changes in grain or seed protein and antinutrient concentrations, have been reported in major food crops when exposed to elevated carbon dioxide, high temperature, drought, and humidity. These changes, in addition to affecting the quantity of indispensable or essential amino acids (IAA), also impact their bioavailability. Therefore, it is important to assess consequences of climate change on grain protein quality. An important tool to measure grain protein quality, is measuring its digestibility at the level of the ileum and its IAA concentration, linked to a metric called the Digestible IAA Score (DIAAS). A minimally invasive technique called the dual isotope tracer technique, which measures IAA digestibility after simultaneous administration of two different intrinsically labelled protein sources, one a test protein (2H/15N) and one a reference protein (13C) of predetermined digestibility, has been used in evaluation of grain protein IAA digestibility, and promises more in the evaluation of changes based on climate. This review discusses climate induced changes to grain protein quality through the prism of IAA digestibility, using the dual isotope tracer technique.

BACKGROUND:Protein quality, evaluated using Digestible Indispensable Amino Acid Score (DIAAS), requires ileal digestibility values of individual indispensable amino acids (IAAs) in each protein. However, true tryptophan (Trp) digestibility has rarely been quantified in humans. OBJECTIVE:To measure the true Trp digestibility and DIAAS of 2H-intrinsically labeled plant and animal protein sources in humans, using the dual isotope tracer technique. METHODS:The true Trp digestibility of 2H intrinsically labeled plant proteins such as whole mung bean (n = 6) and dehulled mung bean (n = 6), chickpea (n = 5), and yellow pea (n = 5), and protein from animal source foods such as egg white (n = 6), whole egg (n = 6), chicken meat (n = 6), and goat milk (n = 7) was determined against the known digestibility of U-13C spirulina whole cell protein as reference, except for goat milk protein that was measured against free crystalline 13C-Trp as reference. Banked samples from earlier studies conducted to determine true IAA digestibility of different protein sources were used for the analysis. DIAAS was calculated for each test protein using digestibility corrected IAA scores (mg IAA/g of protein) in comparison with the IAA requirement score for adults. RESULTS:The true Trp digestibility of whole mung bean, dehulled mung bean, chickpea, yellow pea, egg white, whole egg, chicken meat, and goat milk were 67.6 ± 3.7%, 74.5 ± 4.4%, 72.6 ± 2.3%, 72.5 ± 2.2%, 89.7 ± 2.5%, 91.4 ± 2.6%, 95.9 ± 2.2%, and 92.8 ± 2.9%, respectively. The true Trp digestibility of plant protein sources was significantly lower than that of animal protein sources (P < 0.05). Trp was not a limiting IAA in all the tested proteins. CONCLUSION:The true Trp digestibility determined in this study ranged from 67.6 ± 3.7% to 95.9 ± 2.2% for whole mung bean and chicken meat, respectively, and adds to the database of individual true IAA digestibility of different protein sources. TRIAL REGISTRATION NUMBER:This study was registered in Clinical Trials Registry of India (CTRI) with registration numbers CTRI/2017/11/010468, CTRI/2020/04/024512, and CTRI/2018/03/012265.