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.

Quinoa is a nutritional powerhouse, packed with protein, fiber, vitamins and minerals. However, it also contains certain compounds that impact nutrient availability. To address this, processing methods like soaking and germination have emerged as effective traditional treatments. They not only enhance the nutritional and bioactive potential but also diminish the anti-nutritional components in these grains, elevating their overall quality. This study examines the effect of soaking and germination treatments on anti-nutritional characteristics of quinoa. The result shows that an increase in germination percentages increases with longer germination times. Notably, seeds soaked in lukewarm water containing 2% salt for 24 hours showed the highest germination percentage (82.89%), while the number of non-germinated (16.27%) and abnormally germinated (0.32%) seeds decreased and greatest radical length (10.25 mm) when compared to seeds soaked in normal water. However, as the germination period extended, quinoa exhibited increased levels of vitamin C, notably more pronounced in lukewarm water with a 2% salt concentration. Additionally, germinated quinoa presents reduced levels of phytic acid (68.22 mg/100 g), tannin (0.36 mg/100 g), saponin (75.13 mg/100 g), and oxalates (42.55 mg/100 g) in comparison to raw quinoa. Hence, soaking and germination emerge as effective methods for reducing antinutritional components and enhancing the nutritional and bioactive potential of quinoa.

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.

Assessing the digestive and absorptive capacity of the gastro-intestinal tract (GIT) using minimally- or non-invasive methods, particularly in children, has been difficult owing to the complex physiology and variability in functional measurements. However, measuring GIT function is increasingly important with the emerging relevance of childhood environmental enteropathy (EE) as a mediating factor in linear growth faltering, severe acute malnutrition, poor oral vaccine uptake and impaired cognition. In EE, sub-optimal nutrient digestion and absorption (malabsorption) forms the critical link to the conditions mentioned above. The present narrative review discusses probable mechanisms that can cause malabsorption of macronutrients, along with mechanistic and experimental evidence, in children (if not, in adults) with EE. The strengths and limitations of the human experimental studies are examined in relation to a battery of existing and potential tests that are used to measure malabsorption. From the available studies conducted in children, lactose and fat malabsorption are more likely to occur in EE. Breath tests (non-invasive) measuring carbohydrate (13C-starch/sucrose/lactose), fat (13C-mixed triglyceride) and dipeptide (benzoyl-L-tyrosyl-L-1-13C-alanine) malabsorption with modifications to the existing protocols seem suitable for use in children with EE. Future research should focus on understanding the degree of macronutrient malabsorption using these tests, in different settings, and link them to functional outcomes (such as growth, muscle strength, cognition).

Background: The digestion and absorption of ingested protein may be reduced in children with environmental enteric dysfunction (EED), reducing systemic amino acid availability for protein synthesis with resultant growth faltering. This has not been directly measured in children with EED and associated growth faltering.Objectives: To evaluate the systemic availability of algal (spirulina) and legume (mung bean) indispensable amino acids (IAAs) in children with EED.Methods: Indian children (18-24 mo) from urban slums were assigned to EED (n = 24) or no-EED (control, n = 17) groups based on the lactulose rhamnose test, where the lactulose rhamnose ratio cutoff for diagnosing EED (>0.068) was the mean thorn 2SD of its distribution in healthy, age-, and sex matched children of high socioeconomic status. Fecal biomarkers of EED were also measured. Systemic IAA availability was calculated from the plasma: meal IAA enrichment ratio for each protein. True ileal mung bean IAA digestibility was measured by the dual isotope tracer method using spirulina protein as reference. Co-administration of free 13C6-phenylalanine allowed for estimating true ileal phenylalanine digestibility of both proteins, and a phenylalanine absorption index. Results: There was no significant difference (independent t-test) in the systemic IAA availability from spirulina or mung bean protein between EED and no-EED groups. There was no between-group difference in true ileal phenylalanine digestibility and its absorption index, or in mung bean IAA digestibility.Conclusions: The systemic IAA availability of algal and legume protein, or the latter's IAA/phenylalanine digestibility, is not significantly reduced in children with EED and does not correlate with linear growth.This study was registered in Clinical Trials Registry of India (CTRI) with registration number: CTRI/2017/02/007921.

Background/Objectives Chronic immune activation in Environmental Enteric Dysfunction (EED) could lead to increased fed-state metabolic rate (MR) or total energy expenditure (TEE) and limit the energy available for optimal linear growth. In a secondary analysis, MR and TEE were compared in young Indian children from urban slums, with and without stunting or EED. Subjects/Methods Children (18–24 months, n = 69) were classified into non-stunted (LAZ ≥ −2) and stunted (LAZ < −2), and no-EED (lactulose rhamnose ratio, LRR < 0.068) and EED (LRR ≥ 0.068) groups. Associations between MR and TEE (kcal per kg bodyweight [BW] or fat free mass [FFM]) with stunting and EED were examined using logistic regression. Results Median TEE was significantly higher in the stunted compared to non-stunted group (76.8 versus 92.0 kcal/kg BW/day, p = <0.01). The adjusted (for sex, FFM, EED) odds ratio (AOR) for stunting with TEE (kcal/day) was 1.01 (95% CI: 1.00, 1.01), but importantly, there was no interaction between EED and TEE. The median TEE was also significantly higher in the EED compared to the no-EED group (89.1 vs 76.8 kcal/kg BW/day, p = 0.02), and the AOR (adjusted for sex and TEE) for stunting with EED was 3.56 (95% CI:1.09, 11.63). MR (per kg BW or FFM) was not associated with stunting or EED. Conclusion Higher TEE and presence of EED were independently and positively associated with stunting. Children with EED also had higher TEE but not MR. Energetically, the higher TEE in stunted children may not specifically be linked to the presence of EED, although the latter independently had higher odds of stunting.

PURPOSE OF REVIEW:Children with linear growth faltering refractory to nutritional management show evidence of environmental enteropathy, which may compromise nutrient availability. Protein could be particularly affected, due to the possibility of sub-optimal digestibility and/or increase in requirement for immune response. This increase in protein requirement along with poor intake could potentially lead to increased breakdown of body protein sources and in turn a depleted protein state. The present review focuses on protein status in children at risk of linear growth faltering and environmental enteropathy. One pig study is also presented.RECENT FINDINGS:There is consistent evidence of low circulating essential and conditionally essential amino acids, in children. One study showed no difference in protein synthesis/breakdown, and fat free mass (FFM) in children at risk of linear growth faltering and environmental enteropathy. Weanling pigs exposed to nutrient deprivation showed a decrease in plasma albumin, with a slower rate of weight and length accretion, and a lower FFM.SUMMARY:These findings emphasize the need for improving intake of high-quality protein in children living in regions with a high prevalence of environmental enteropathy, with careful studies of the effect on growth rate and protein status.

Background In young children, associations between linear growth faltering, environmental enteric dysfunction (EED), and the plasma kynurenine (Kyn)/tryptophan (Trp) ratio (KTR) have led to the proposal that higher Trp catabolism in response to intestinal/systemic inflammation limits Trp availability for protein synthesis, resulting in impaired growth. Objectives We sought to estimate the Trp oxidation rate and the Trp conversion rate to Kyn in young children with and without EED. Methods Children aged 18-24 mo, from urban slums, were assigned to EED (n = 19) or no-EED (n = 26) groups on the basis of a urinary lactulose/rhamnose ratio (LRR) cutoff based on mean + 2 SDs of LRR (>= 0.068) in normal age- and sex-matched, high-socioeconomic status children. Plasma KTR and fecal biomarkers of EED were measured. Trp oxidation in the fed state was measured using C-13(1)-Trp in an oral plateau feeding protocol. Results The median (quartile 1, quartile 3) fasted KTR was 0.089 (0.066, 0.110) in children with EED compared with 0.070 (0.050, 0.093) in children with no EED (P = 0.077). However, there was no difference in fed-state Trp oxidation [median (quartile 1, quartile 3) 3.1 (1.3, 5.8) compared with 3.9 (1.8, 6.0) mu mol/kg FFM/h, respectively, P = 0.617] or Trp availability for protein synthesis [42.6 (36.5, 45.7) compared with 42.5 (37.9, 46.9) mu mol/kg FFM/h, respectively, P = 0.868] between the groups. In contrast, the median (quartile 1, quartile 3) fractional synthesis rates of Kyn [12.5 (5.4, 20.0) compared with 21.3 (16.1, 24.7) %pool/h, P = 0.005] and the fraction of Ala derived from Trp [0.007 (0.005, 0.015) compared with 0.012 (0.008, 0.018), P = 0.037], respectively, in the plasma compartment were significantly slower in the EED group. Fecal biomarkers of EED did not differ between the groups. Conclusions The static plasma KTR value is not a good indicator of the dynamic Trp flux down its oxidative pathway. In a poor sanitary environment, children without EED actually have a faster Kyn synthesis rate, which might be beneficial, because of the cytoprotective and anti-inflammatory functions of downstream metabolites. This study was registered in the Clinical Trials Registry of India as CTRI/2017/02/007921.

BACKGROUND AND OBJECTIVES South Asians are known to have excess adiposity at a lower body mass index, with truncal fat accumulation. Whether this confers higher risk to develop severe COVID-19 is not known. This study evaluated body mass index, body fat mass and waist circumference as risk factors for COVID-19 severity and its progression, in South Asian adults. METHODS AND STUDY DESIGN Details of COVID-19 patients (19-90 years) were obtained prospectively, along with weight, height, waist circumference and body fat mass assessed by bioelectrical impedance analysis. Binomial logistic and Poisson regression were performed to test associations between waist circumference, body fat mass and body mass index to evaluate the adjusted OR or relative risk for disease severity at admission and length of stay. RESULTS After adjusting for age, sex, height and co-morbidities, body mass index >23 kg/m2 (adjusted OR 2.758, 95% CI 1.025, 7.427), waist circumference (adjusted OR 1.047, 95% CI 1.002, 1.093) and body fat mass (adjusted OR 1.111, 95% CI 1.013, 1.219) were associated with a significant risk for disease severity at admission, while only waist circumference (adjusted relative risk 1.004, 95% CI 1.001, 1.008), and body fat mass (adjusted relative risk 1.011, 95% CI 1.003, 1.018), were associated with a significantly longer length of stay. CONCLUSIONS Body mass index, at a lower cut-off of >23 kg/m2, is a significant risk factor for COVID-19 disease severity in the group of patients studied. The waist circumference and body fat mass are also good indicators for both severity at admission and length of stay.

BACKGROUND:The current estimates of energy and protein to bridge nutrient gap in the beneficiaries of the Integrated Child Development Services (ICDS) supplementary nutrition program use sub-optimal methodology for deficit calculation.OBJECTIVE:To estimate the nutrient deficit and the risk of inadequate nutrient intake in beneficiaries of the ICDS, aged 6-36 months, using individual 24-hour diet recalls, from districts of Chitradurga and Davanagere in Karnataka.STUDY DESIGN:Cross-sectional design.PARTICIPANTS:Children (aged 6 to 36 months) registered as beneficiaries of the ICDS in these districts.METHODS:Data were collected on socio-demographic factors, child feeding patterns, perception and usage of take home ration (THR), between August to October, 2019. Three non-consecutive days' 24-hour diet recall data of children were obtained from mothers, and anthropometric measurements were taken. The proportion of children at risk of inadequate nutrient intakes was estimated using the probability approach. Assuming that 50% of a healthy population will be at risk of nutrient inadequacy such that intake and requirement distributions overlap, the proportion at actual risk of nutrient inadequacy (≥50%) was calculated.RESULTS:A combined district analysis showed a median energy deficit of 109 kcal and 161 kcal in children belonging to the age groups of 6-12 month and 13-36 month, respectively. The actual risk of inadequate intake for both age groups ranged between 12-47% for fat and other micronutrient (iron, calcium, zinc, folate, vitamin B12 and vitamin A), despite breastfeeding, complementary feeding and reported THR use.CONCLUSION:Children who receive supplementary nutrition as part of the national program fail to meet their nutrient requirements that are essential for growth and development. The study results may help in strengthening the IYCF counselling and in modification of the existing THR, with quality and cost implications.

Gut function remains largely underinvestigated in undernutrition, despite its critical role in essential nutrient digestion, absorption and assimilation. In areas of high enteropathogen burden, alterations in gut barrier function and subsequent inflammatory effects are observable but remain poorly characterised. Environmental enteropathy (EE)—a condition that affects both gut morphology and function and is characterised by blunted villi, inflammation and increased permeability—is thought to play a role in impaired linear growth (stunting) and severe acute malnutrition. However, the lack of tools to quantitatively characterise gut functional capacity has hampered both our understanding of gut pathogenesis in undernutrition and evaluation of gut-targeted therapies to accelerate nutritional recovery. Here we survey the technology landscape for potential solutions to improve assessment of gut function, focussing on devices that could be deployed at point-of-care in low-income and middle-income countries (LMICs). We assess the potential for technological innovation to assess gut morphology, function, barrier integrity and immune response in undernutrition, and highlight the approaches that are currently most suitable for deployment and development. This article focuses on EE and undernutrition in LMICs, but many of these technologies may also become useful in monitoring of other gut pathologies.

Gut microbiota has been implicated as a modifier of childhood growth. Here, 16S rRNA sequencing-based fecal microbiota profiles of 18-24 month old Indian children were evaluated (n = 41), in relation to their anthropometric parameters, intestinal permeability, body composition and total energy expenditure. Pathway analyses were conducted to assess microbial functions related to stunting, underweight and wasting. The fecal microbiota was enriched in Prevotella 9, Bifidobacterium and Escherichia-Shigella. Weight, weight-for-age Z-scores (WAZ) and weight-for-length Z-scores (WLZ), along with age, acted as covariates of microbiota variation specifically in boys (n = 23). Bifidobacterium longum subsp longum abundance was positively associated with WAZ while Bifidobacterium bifidum and Bifidobacterium breve abundances were negatively associated with age. The lipopolysaccharide biosynthesis pathway was upregulated in stunted (n = 16) and wasted (n = 8) children. Findings from this study indicate that child sex may be a critical modifier of the role of gut microbiota on childhood growth.

BACKGROUND Lysine rich foods such as milk and legumes serve as important food additions to the lysine deficient cereal-based diets of vegetarian populations in low- and middle-income countries (LMICs) to alleviate the risk of quality corrected dietary protein inadequacy. Dietary protein quality can be determined by estimating the metabolic availability (MA) of lysine. OBJECTIVES The study aimed to estimate the MA of lysine in spray-dried cow milk powder (SMP), heat-treated spray-dried cow milk powder (HSMP), and a habitually consumed cereal-legume based vegetarian meal (VM), using the indicator amino acid oxidation (IAAO) slope-ratio method. METHODS The MA of lysine in SMP, HSMP, and VM was estimated in 7 healthy young men aged 19-24 y with BMI of 21.5 ± 0.5 kg/m2 in a repeated measures design. The IAAO response slopes with 2 graded lysine intakes (10.5 and 15.0 mg·kg-1·d-1) from the SMP and VM were compared with the response slope generated with 3 graded crystalline lysine intakes (6.0, 10.5, and 15.0 mg·kg-1·d-1) at the subrequirement level. To produce HSMP, pasteurized cow milk was heat treated and spray dried. The MA of lysine in HSMP was tested at a single level of lysine intake (15 mg·kg-1·d-1). A total of 8 IAAO experiments were conducted on each participant in randomized order. The IAAO slopes were estimated using a linear mixed-effect regression model. RESULTS The MA of lysine in SMP, HSMP, and VM was 91.9%, 69.9%, and 86.6% respectively. CONCLUSIONS Heat treatment reduced the MA of lysine by 22% in HSMP compared with SMP in healthy Indian adults. The lysine MA estimates can be used to optimize lysine limited cereal-based diets, with the addition of appropriately processed legumes and milk powder, to meet the protein requirement. This trial was registered at Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2019/08/020568.

The recent National Family Health Survey (NFHS-4, 2016) reports a national average of 18% for low birthweight (LBW) and 38% for stunting in children <5 years. Nutrition and environmental influences (chronic enteric pathogenic exposure through poor water, sanitation, and hygiene) are two critical factors that impact the health outcomes of the populxation. This is particularly relevant for vulnerable age groups such as pregnant women and children <5 years, who bear long-lasting and intergenerational consequences of impoverished nutrition and suboptimal living conditions. The present review provides, for the first time, an analysis of indispensable amino acid (IAA) requirements for pregnant women, separately for the second and third trimesters, using protein accretion data from a recent Indian study. Furthermore, using these estimates for pregnancy, and the current IAA requirements for young children, the quality of protein was assessed in Indian diets consumed by pregnant women and children (1-3 and 4-6 years) from national representative rural National Nutrition Monitoring Bureau survey. The assessment was considered in the context of an adverse environment and in relation to outcomes such as LBW, stunting, and underweight. Finally, an assessment was made of the proportion of the surveyed population at risk of dietary quality protein inadequacy and implications for planning nutrition intervention programmes. Specifically, state-wise estimates of the risk of quality protein inadequacy are provided, in addition to evaluations of additional dietary supplementation, which could inform the policy of supplementary nutrition programmes to improve health outcomes.

IntroductionEnvironmental enteropathy (EE) is suspected to be a cause of growth faltering in children with sustained exposure to enteric pathogens, typically in resource-limited settings. A major hindrance to EE research is the lack of sensitive, non-invasive biomarkers. Current biomarkers measure intestinal permeability and inflammation, but not the functional capacity of the gut. Australian researchers have demonstrated proof of concept for an EE breath test based on using naturally 13C-enriched sucrose, derived from maize, to assay intestinal sucrase activity, a digestive enzyme that is impaired in villus blunting. Here, we describe a coordinated research project to optimise, validate and evaluate the usability of a breath test protocol based on highly enriched 13C-sucrose to quantify physiological dysfunction in EE in relevant target populations.Methods and analysisWe use the 13C-sucrose breath test (13C-SBT) to evaluate intestinal sucrase activity in two phases. First, an optimisation and validation phase will (1) confirm that a 13C-SBT using highly enriched sucrose tracers reports similar information to the naturally enriched 13C-SBT; (2) examine the dose–response relationship of the test to an intestinal sucrase inhibitor; (3) validate the 13C-SBT in paediatric coeliac disease (4) validate the highly enriched 13C-SBT against EE defined by biopsy in adults and (5) validate the 13C-SBT against EE defined by the urinary lactulose:rhamnose ratio (LR) among children in Peru. Second, a cross-sectional study will be conducted in six resource-limited countries (Bangladesh, India, Jamaica, Kenya, Peru and Zambia) to test the usability of the optimised 13C-SBT to assess EE among 600 children aged 12–15 months old.Ethics and disseminationEthical approval will be obtained from each participating study site. By working as a consortium, the test, if shown to be informative of EE, will demonstrate strong evidence for utility across diverse, low-income and middle-income country paediatric populations.Trial registration numberNCT04109352; Pre-results.