Protein status in relation to linear growth faltering and environmental enteropathy.

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.

The Systemic Availability of Indispensable Amino Acids from Orally Ingested Algal and Legume Protein in Young Children at Risk of Environmental Enteric Dysfunction.

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 + 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.

Free living total energy expenditure in young South Indian children at risk of environmental enteric dysfunction and its relation to faltered linear growth.

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.

Tryptophan oxidation in young children with environmental enteric dysfunction classified by the lactulose rhamnose ratio.

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 13C1-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) µmol/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) µmol/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.

Estimated Deficits in Nutrient Intake of ICDS Beneficiaries Who Receive Take Home Ration at Two Districts in Karnataka.

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.

Central obesity in low BMI as a risk factor for COVID-19 severity in South Indians.

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.

Understanding the role of the gut in undernutrition: what can technology tell us?

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 profiles of young South Indian children: Child sex-specific relations with growth.

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.

Goat milk protein digestibility in relation to intestinal function.

BACKGROUND: Milk is an important high-quality animal protein source in low- and middle-income countries (LMICs). Although the true ileal digestibility and absorption of milk has been shown to be high in French adults, this may be lower in individuals from LMICs who are at risk of environmental enteropathy. OBJECTIVE: To determine the true ileal indispensable amino acid (IAA) digestibility of intrinsically labeled goat milk protein in South Indian women of reproductive age (WRA), using the dual-isotope tracer technique, and to measure intestinal absorption of amino acid and inert sugar in the same participants using L-allo-isoleucine and a dual-sugar assay. METHODS: Milk with 2H-labeled protein collected from a lactating goat fed intrinsically 2H-labeled fodder (maize and cowpea) was spray dried. Labeled milk protein was administered in a plateau feeding protocol to WRA with normal BMI, in whom urinary lactulose and mannitol recovery and the lactulose/mannitol ratio (LMR) were measured, to determine its true ileal IAA digestibility by the dual-isotope tracer technique with a reference U-13C-amino acid mixture. A phenylalanine absorption index was calculated from the plasma to meal ratio of 13C9 phenylalanine within the digestibility protocol. On a separate day, the allo-isoleucine absorption index was estimated from the ratio of plasma allo-isoleucine enrichments after oral 13C6-15N-L- and intravenous 2H10-L-allo-isoleucine administration. RESULTS: The means ± SDs of true ileal IAA digestibility of goat milk protein, lactulose and mannitol recovery, LMR, allo-isoleucine and phenylalanine absorption index were 94.0 ± 2.9%, 0.09 ± 0.03%, 7.9 ± 2.3%, 0.012 ± 0.004, 88.4 ± 3.8% and 24.5 ± 1.6%, respectively. The LMR correlated with the allo-isoleucine absorption index (rs = -0.93, P = 0.008). CONCLUSION: The true ileal digestibility of goat milk protein in South Indian WRA with normal intestinal absorptive function and integrity was comparable to earlier estimates in healthy French adults.

Protein intakes of pregnant women and children in India-protein quality implications.

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.

Optimisation, validation and field applicability of a 13C-sucrose breath test to assess intestinal function in environmental enteropathy among children in resource poor settings: study protocol for a prospective study in Bangladesh, India, Kenya, Jamaica, Peru and Zambia.

INTRODUCTION: Environmental 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 ANALYSIS: We 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 DISSEMINATION: Ethical 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 NUMBER: NCT04109352; Pre-results.

An uncertainty estimate of the prevalence of stunting in national surveys: the need for better precision.

BACKGROUND: Stunting is determined by using the World Health Organization (WHO) child growth standard which was developed using precise measurements. However, it is unlikely that large scale surveys maintain the same level of rigour and precision when measuring the height of children. The population measure of stunting in children is sensitive to over-dispersion, and the high prevalence of stunting observed in surveys in low and middle-income countries (LMIC) could partly be due to lower measurement precison. OBJECTIVES: To quantify the incongruence in the dispersion of height-for-age in national surveys of < 5 y children, in relation to the standard WHO Multicenter Growth Reference Study (MGRS), and propose a measure of uncertainty in population measures of stunting. METHODS: An uncertainty factor was proposed and measured from the observed incongruence in dispersion of the height-for-age of < 5 y children in the MGRS against carefully matched populations from the Demographic Health Survey of 17 countries ('test datasets', based on the availability of data). This also allowed for the determination of uncertainty-corrected prevalence of stunting (height-for-age Z score < - 2) in < 5 y children. RESULTS: The uncertainty factor was estimated for 17 LMICs. This ranged from 0.9 to 2.1 for Peru and Egypt respectively (reference value 1). As an explicit country example, the dispersion of height-for-age in the Indian National Family Health Survey-4 test dataset was 39% higher than the MGRS study, with an uncertainty factor of 1.39. From this, the uncertainty-adjusted Indian national stunting prevalence estimate reduced to 18.7% from the unadjusted estimate of 36.2%. CONCLUSIONS: This study proposes a robust statistical method to estimate uncertainty in stunting prevalence estimates due to incongruent dispersions of height measured in national surveys for children < 5 years in relation to the WHO height-for-age standard. The uncertainty is partly due to population heterogeneity, but also due to measurement precision, and calls for better quality in these measurements.

Metabolic Availability of Lysine in Milk and a Vegetarian Cereal-Legume Meal Determined by the Indicator Amino Acid Oxidation Method in Indian Men.

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.

Protein Quality Assessment of Follow-up Formula for Young Children and Ready-to-Use Therapeutic Foods: Recommendations by the FAO Expert Working Group in 2017.

The FAO of the UN convened an Expert Working Group meeting to provide recommendations related to protein quality evaluation of Follow-up Formula for Young Children (FUF-YC) and Ready-to-Use Therapeutic Foods (RUTFs). The protein and amino acid (AA) scoring patterns for the target age groups were defined and recommendations provided on the use of currently available protein and indispensable AA digestibility data. For FUF-YC, an age category of 1-2.9 y was identified, and a matching protein requirement of 0.86 g · kg-1 · d-1 with corresponding AA requirements were recommended. For RUTF, the protein requirement recommended was 2.82 g · kg-1 · d-1, to achieve a catch-up weight gain of 10 g · kg-1 · d-1 in children recovering from severe acute malnutrition. The AA requirements were factorially derived based on the adult protein requirement for maintenance and tissue AA composition. A flowchart was proposed for the best available methods to estimate digestibility coefficients (of either protein or AAs), in the following order: human, growing pig, and rat true ileal AA digestibility values. Where this is not possible, fecal protein digestibility values should be used. The Expert Working Group recommends the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS), with existing protein digestibility values, or the Digestible Indispensable Amino Acid Score provided that individual AA digestibility values are available for protein quality evaluation using the latter score. The Group also recommends the use of ileal digestibility of protein or of AAs for plant-based protein sources, recognizing the possible effects of antinutritional factors and impaired gut function. A PDCAAS score of ≥90% can be considered adequate for these formulations, whereas with a score <90%, the quantity of protein should be increased to meet the requirements. Regardless of the protein quality score, the ability of formulations to support growth in the target population should be evaluated. Future research recommendations are also proposed based on the knowledge gaps identified.

True ileal digestibility of legumes determined by dual-isotope tracer method in Indian adults.

BACKGROUND: Good-quality plant protein sources are important for protein adequacy in a balanced diet. Legumes are known to be a source of good quality plant protein, but the true ileal digestibility of indispensable amino acids (IAAs) of commonly consumed legumes is not known in humans. OBJECTIVES: In this study we measured the true ileal IAA digestibility of 2H-intrinsically labeled chickpea, yellow pea, and mung bean (hulled and dehulled) protein, using the dual-isotope tracer technique referenced to a standard protein ([U-13C] spirulina). The study also aimed to validate the use of [U-13C] spirulina as a reference protein in this method. METHODS: 2H-intrinsically labeled legumes, obtained by watering plants with deuterium oxide (2H2O), were administered in a plateau feeding method to healthy Indian adults to measure their true ileal IAA digestibility with the dual-isotope tracer technique, using [U-13C] spirulina protein or a 13C-algal IAA mixture as the standard. RESULT: The true ileal IAA digestibilities (mean ± SD) of chickpea, yellow pea, and mung bean were 74.6 ± 0.8%, 71.6 ± 1.3%, and 63.2 ± 1.5%, respectively. The true mean ileal IAA digestibility of mung bean when referenced to [U-13C] spirulina protein or a 13C-algal IAA mixture did not differ significantly (63.2 ± 1.5% versus 64.0 ± 2.4%, P > 0.05). The true ileal IAA digestibility of mung bean improved to 70.9 ± 2.1% after dehulling. CONCLUSIONS: The true mean ileal IAA digestibility of legumes in healthy Indian adults was lower than expected. Traditional processing techniques such as dehulling improve protein digestibility by about 8%. This study was registered in the Clinical Trials Registry of India (CTRI): CTRI/2017/11/010468 (http://ctri.nic.in, accessed on 28/03/2019).

Daily Iron Requirements in Healthy Indian Children and Adolescents.

OBJECTIVE: This study aimed to define the estimated average requirement and the recommended dietary allowance of iron for Indian children and adolescents. Methods: The Estimated average requirement was derived for children aged 1-17y, from the mean bioavailability-adjusted daily physiological iron requirement, which in turn was estimated using a factorial method. This consisted of mean daily iron losses from the body and additional iron required for tissue growth and storage, while also defining the variance of each factor to derive the Recommended dietary allowance. RESULTS: Results: The estimated average requirement of iron for children ranged from 5.6 to 11.0 mg/d in children aged 1-9y. For adolescents aged 10-17y, these ranged from 10.8 to 18.4 mg/d and 15.4 to 18.5 mg/d for adolescent boys and girls, respectively. CONCLUSIONS: New estimates of estimated average requirement for iron in Indian children are presented, and same may be used to inform iron supplementation and food fortification policies.

Co-ingestion of Black Tea Reduces the Indispensable Amino Acid Digestibility of Hens' Egg in Indian Adults.

BACKGROUND: Tea, a commonly consumed beverage, contains high amounts of polyphenols that can impair protein digestibility, as demonstrated in vitro. There are no human studies examining the inhibitory influence of tea polyphenols (TPP) on high-quality protein digestibility. OBJECTIVE: The aim of this study was to determine the effect of black tea on the true indispensable amino acid (IAA) digestibility of whole boiled egg protein, in healthy adult humans, through use of a dual isotope tracer approach. METHODS: The effect of black TPP (4.6 mg/mL, ingested as a beverage with the meal) on 2H-labeled whole boiled egg protein, administered with ghee rice and tomato curry, was measured with reference to 13C-spirulina protein in healthy Indian adults aged 20-27 y of both sexes with BMI of 22.0 ± 2.8 kg/m2. The results were then compared to previously determined whole egg mean IAA digestibility measured by the same method, without black tea, in the same subjects (n = 5). To correct for any independent effect of TPP on spirulina protein (used as a standard protein), the true IAA digestibility of 13C-spirulina protein was independently measured with reference to a 2H-amino acid mixture, with and without co-ingestion of black tea, in 3 of the same subjects. RESULTS: The true IAA digestibility of whole boiled egg protein significantly decreased by 17% when co-ingested with black tea. However, there was no significant reduction in the true IAA digestibility of spirulina protein when co-ingested with black tea. CONCLUSIONS: TPP protein interactions reduced whole egg digestibility in healthy Indian adults but had minimal effect on spirulina protein digestibility. In populations who are at risk of dietary quality protein inadequacy, the consumption of tea during or after a meal can further increase the risk of inadequacy. This trial was registered at Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.

Protein-quality evaluation of complementary foods in Indian children.

BACKGROUND: The types of food in complementary feeding of infants and young children are important for growth and development. Food protein quality, as measured by the Digestible Indispensable Amino Acid Score (DIAAS), requires the determination of true ileal digestibility of indispensable amino acids (IAAs) in children. OBJECTIVES: First, the aim of this study was to measure the true ileal IAA digestibility of 4 (rice, finger millet, mung bean, and hen egg) commonly consumed complementary foods in children aged <2 y using the dual-isotope tracer method. Second, we calculated the DIAAS of complementary feeding diets and their relation to stunting in a representative Indian rural population. DESIGN: Rice, finger millet, and mung bean were intrinsically labeled with deuterium oxide (2H2O), whereas egg was labeled through oral dosing of hens with a uniformly 2H-labeled amino acid mixture. True ileal IAA digestibility was determined by the dual-isotope tracer technique. The DIAAS of complementary food protein was calculated in children aged 1-3 y from a nationally representative survey to evaluate its relation with stunting. RESULTS: True ileal IAA digestibility was lowest in mung bean (65.2% ± 7.1%), followed by finger millet (68.4 %± 5.3%) and rice (78.5% ± 3.5%), and was highest for egg (87.4% ± 4.0%). There was a significant inverse correlation of complementary food DIAAS with stunting in survey data (r = -0.66, P = 0.044). The addition of egg or milk to nationally representative complementary diets theoretically improved the DIAAS from 80 to 100. CONCLUSIONS: The true ileal IAA digestibility of 4 foods commonly consumed in complementary diets showed that the DIAAS was associated with stunting and reinforces the importance of including animal source food (ASF) in diets to improve growth. This trial was registered at http://ctri.nic.in/clinicaltrials/login.php as CTRI/2017/02/007921.

Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults.

Background: Protein quality assessment through the Digestible Indispensable Amino Acid Score requires accurate measurements of true ileal protein and amino acid digestibility, for which a dual isotope technique was recently developed. However, the ileal digestibility of indispensable amino acids (IAA) in humans from high-quality proteins is not well known. Objective: The aim of this study was to intrinsically label hen's egg and meat protein by the use of uniformly 2H-labeled amino acids, and to measure their true ileal indispensable amino acid (IAA) digestibility via the dual isotope method in humans. Design: 2H-labeled lyophilized boiled egg white protein, whole boiled egg, and cooked meat were obtained from layer hens (BV-300) administered a uniformly 2H-labeled amino acid mix orally for 35 d with their daily feed. The ileal IAA digestibility of these proteins was determined with reference to digestibility of previously characterized [U-13C]spirulina in a dual tracer method in healthy Indian subjects whose intestinal health was measured by the plasma kynurenine-to-tryptophan (KT) ratio. Results: All subjects had normal KT ratios. The mean ± SD true ileal IAA digestibility of 2H-labeled egg white protein, whole boiled egg, and cooked meat was 86.3% ± 4.6%, 89.4% ± 4.5%, and 92.0% ± 2.8%, respectively. Leucine digestibility correlated with the KT ratio (r = -0.772; P = 0.009). Conclusions: Uniformly 2H-labeled hen's egg and meat protein can be used to measure ileal IAA digestibility by the dual isotope tracer approach in humans. The mean IAA digestibility values for these high-quality proteins in the healthy Indians studied were similar to values obtained in earlier human and animal experiments. Leucine digestibility in these meal matrices correlated with the KT ratio, but this aspect needs further evaluation. This trial was registered at the Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.