A Combined Intervention of Zinc, Multiple Micronutrients, and Albendazole Does Not Ameliorate Environmental Enteric Dysfunction or Stunting in Rural Malawian Children in a Double-Blind Randomized Controlled Trial

Effects of Vitamin D-3 Supplementation During Pregnancy and Lactation on Maternal and Infant Biomarkers of Environmental Enteric Dysfunction, Systemic Inflammation, and Growth: A Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Environmental enteric dysfunction (EED) is an acquired, subclinical state of intestinal inflammation common in children and adults in low-income and middle-income countries. Although vitamin D-3 supplementation has purported anti-inflammatory properties, its ability to ameliorate biomarkers of EED remains unclear.

OBJECTIVES

This study aimed to examine the effects of maternal vitamin D-3 supplementation during pregnancy and lactation on biomarkers of EED, systemic inflammation, and growth in women living with HIV and their infants in Dar es Salaam, Tanzania.

METHODS

We conducted subgroup analyses among randomly selected mothers (n = 720) and infants (n = 365 at 6 wk of age, and n = 266 at 6 mo of age) who participated in a randomized, triple-blind, placebo-controlled trial of daily maternal 3000 IU vitamin D-3 supplementation from the second trimester of pregnancy until 1 y postpartum. Biomarkers of EED (soluble CD14 and intestinal fatty acid-binding protein), systemic inflammation (C-reactive protein and α1-acid glycoprotein), and growth factors (insulin-like growth factor 1 and fibroblast growth factor 21) were measured via the Micronutrient and Environmental Enteric Dysfunction Assessment Tool. Anti-flagellin and anti-lipopolysaccharide immunoglobulins were measured via enzyme-linked immunosorbent assay. Comparisons by randomized treatment arm were performed using ordinary least squares regression models with log2-transformed biomarkers.

RESULTS

At 32 wk of gestation, intestinal fatty acid-binding protein (β: -0.19; P = 0.03) and α1-acid glycoprotein (β:-0.11; P = 0.04) were significantly lower in mothers in the vitamin D-3 group than those in mothers in the placebo group. At 6 wk of age, insulin-like growth factor 1 (β:-0.31; P = 0.03) was significantly lower in infants whose mothers were in the vitamin D-3 group than that in infants whose mothers were in the placebo group.

CONCLUSIONS

Vitamin D-3 supplementation during pregnancy and lactation reduced selected EED and systemic inflammation biomarkers among women living with HIV. While the effects of maternal vitamin D-3 supplementation do not appear to extend to infants, there may be an effect on growth factors. This trial was registered at clinicaltrials.gov as NCT02305927 (https://clinicaltrials.gov/study/NCT02305927).

Exploratory Analysis of Selected Components of the mTOR Pathway Reveals Potentially Crucial Associations with Childhood Malnutrition

Dysregulations in the mammalian target of rapamycin (mTOR) pathway are associated with several human anomalies. We aimed to elucidate possible implications for potential aberrations in the mTOR pathway with childhood malnutrition. We analyzed the activity of phospho-mTORC1 and the expressions of several mTOR pathway genes, namely: MTOR, TSC1, LAMTOR2, RPS6K1 and RICTOR from peripheral blood mononuclear cells isolated from venous blood of children suffering from different forms of malnutrition and compared them with those from healthy children. Significant reduction in the phosphorylation of mTORC1 was noted, as well as a decrease in expression of LAMTOR2 gene and increase in TSC1 gene expression were observed between malnourished children in comparison to the healthy children. The deregulation in the activity of the TSC1 and LAMTOR2 gene was significantly associated with all forms of childhood malnutrition. Our findings provide key insights into possible down-modulation in the overall activity of the mTOR pathway in childhood malnutrition. Further studies focusing on the analysis of a multitude of components involved in the mTOR pathway both at the gene and protein expression levels are required for conclusive evidence for the aforementioned proposition.

Biomarkers of environmental enteric dysfunction are not consistently associated with linear growth velocity in rural Zimbabwean infants

BACKGROUND

Child stunting remains a poorly understood, prevalent public health problem. Environmental enteric dysfunction (EED) is hypothesized to be an important underlying cause.

OBJECTIVES

Within a subgroup of 1169 children enrolled in the SHINE (Sanitation Hygiene Infant Nutrition Efficacy) trial in rural Zimbabwe, followed longitudinally from birth to 18 mo of age, we evaluated associations between the concentration of 11 EED biomarkers and linear growth velocity.

METHODS

At infant ages 1, 3, 6, 12, and 18 mo, nurses measured child length and collected stool and blood; the lactulose-mannitol urine test was also conducted at all visits except at 1 mo. Stool neopterin, α-1 antitrypsin, myeloperoxidase, and regenerating gene 1β protein; urinary lactulose and mannitol; and plasma kynurenine, tryptophan, C-reactive protein, insulin-like growth factor-1 (IGF-1), soluble CD14, intestinal fatty acid binding protein, and citrulline were measured. We analyzed the change in relative [∆ length-for-age z score (LAZ)/mo] and absolute (∆ length/mo) growth velocity during 4 age intervals (1-3 mo; 3-6 mo; 6-12 mo; and 12-18 mo) per SD increase in biomarker concentration at the start of each age interval.

RESULTS

In fully adjusted models, we observed only 3 small, statistically significant associations: kynurenine:tryptophan ratio at 12 mo was associated with decreased mean LAZ velocity during the 12-18 mo interval (-0.015 LAZ/mo; 95% CI: -0.029, -0.001 LAZ/mo); mannitol excretion at 6 mo was associated with increased LAZ velocity during the 6-12 mo interval (0.013 LAZ/mo; 95% CI: 0.001, 0.025 LAZ/mo), and plasma IGF-1 at 1 mo was associated with increased LAZ velocity during the 1-3 mo interval (0.118 LAZ/mo; 95% CI: 0.024, 0.211 LAZ/mo). Results for absolute growth velocity were similar, except IGF-1 was also associated with growth during the 12-18 mo interval. We found no other associations between any EED biomarker and linear growth velocity.

CONCLUSIONS

None of 11 biomarkers of EED were consistently associated with linear growth among Zimbabwean children.This trial was registered at clinicaltrials.gov as NCT01824940.

The contribution of environmental enteropathy to the global problem of micronutrient deficiency

Sometimes referred to as hidden hunger, micronutrient deficiencies persist on a global scale. For some micronutrients this appears to be due to inadequate intake, for others intake may not match increased requirements. However, for most micronutrient deficiencies there is uncertainty as to the dominant driver, and the question about the contribution of malabsorption is open. Environmental enteropathy (EE), formerly referred to as tropical enteropathy and also referred to as environmental enteric dysfunction, is an asymptomatic disorder of small intestinal structure and function which is very highly prevalent in many disadvantaged populations. Recent studies of the pathology and microbiology of this disorder suggest that it is driven by very high pathogen burdens in children and adults living in insanitary environments and is characterised by major derangements of the epithelial cells of the intestinal mucosa. Transcriptomic data suggest that it may lead to impaired digestion and absorption of macronutrients. Given the very high prevalence of EE, marginal malabsorption could have large impacts at population scales. However, the relative contributions of inadequate soil and crop micronutrient contents, inadequate intake, malabsorption and increased requirements are unknown. Malabsorption may compromise attempts to improve micronutrient status, but with the exception of zinc there is currently little evidence to confirm that malabsorption contributes to micronutrient deficiency. Much further research is required to understand the role of malabsorption in hidden hunger, especially in very disadvantaged populations where these deficiencies are most prevalent.

Effects of Water, Sanitation, Handwashing, and Nutritional Interventions on Environmental Enteric Dysfunction in Young Children: A Cluster-randomized, Controlled Trial in Rural Bangladesh

BACKGROUND

We hypothesized that drinking water, sanitation, handwashing (WSH), and nutritional interventions would improve environmental enteric dysfunction (EED), a potential contributor to stunting.

METHODS

Within a subsample of a cluster-randomized, controlled trial in rural Bangladesh, we enrolled pregnant women in 4 arms: control, WSH, child nutrition counseling plus lipid-based nutrient supplements (N), and nutrition plus WSH (N+WSH). Among the birth cohort, we measured biomarkers of gut inflammation (myeloperoxidase, neopterin), permeability (alpha-1-antitrypsin, lactulose, mannitol), and repair (regenerating gene 1β) at median ages 3, 14, and 28 months. Analysis was intention-to-treat.

RESULTS

We assessed 1512 children. At age 3 months, compared to controls, neopterin was reduced by nutrition (-0.21 log nmol/L; 95% confidence interval [CI], -.37, -.05) and N+WSH (-0.20 log nmol/L; 95% CI, -.34, -.06) interventions; similar reductions were observed at 14 months. At 3 months, all interventions reduced lactulose and mannitol (-0.60 to -0.69 log mmol/L). At 28 months, myeloperoxidase was elevated in the WSH and nutrition arms (0.23-0.27 log ng/mL) and lactulose was higher in the WSH arm (0.30 log mmol/L; 95% CI, .07, .53).

CONCLUSIONS

Reductions in permeability and inflammation at ages 3 and 14 months suggest that the interventions promoted healthy intestinal maturation; however, by 28 months, the WSH and nutrition arms showed elevated EED biomarkers. These results underscore the importance of developing a better understanding of EED pathophysiology and targeting interventions early in childhood, when they are likely to have the largest benefit to intestinal health.

CLINICAL TRIALS REGISTRATION

NCT01590095.

Impact of Different Strategies for Delivering Supplemental Zinc on Selected Fecal Markers of Environmental Enteric Dysfunction among Young Laotian Children: A Randomized Controlled Trial

The objective of this study was to assess the impact of different strategies for delivering supplemental zinc on fecal myeloperoxidase (MPO), neopterin (NEO), and calprotectin (CAL) among young Laotian children. In a double-blind controlled trial, children aged 6-23 months were randomized to receive either daily preventive zinc (PZ) tablets (7 mg/day), daily micronutrient powder (MNP; containing 10 mg zinc and 14 other micronutrients), therapeutic zinc (TZ) supplements for diarrhea treatment (20 mg/day for 10 days), or daily placebo powder and followed for ∼36 weeks. Stool samples were collected at baseline and endline. Fecal MPO, NEO, and CAL concentrations were determined in a randomly selected subsample of 720 children using commercially available ELISA kits. At baseline, the mean age was 14.1 ± 4.9 months and prevalence of stunting was 39%. The endline prevalence of stunting was 43%; there was no overall treatment effect on physical growth in the parent trial. At endline, the mean (95% CI) MPO in the PZ group was 1,590 [1,396; 1,811] ng/mL and did not differ from that in the MNP (1,633 [1,434; 1,859] ng/mL), TZ (1,749 [1,535; 1,992] ng/mL), and control (1,612 [1,415; 1,836] ng/mL) groups (P = 0.749). Similarly, there was no overall treatment effect on NEO and CAL concentrations (P = 0.226 and 0.229, respectively). In this population, the provision of PZ or TZ supplements or MNP had no impact on growth or environmental enteric dysfunction (EED) as assessed by fecal MPO, NEO, and CAL. Additional research is needed to better understand the etiology and proposed mechanisms of EED pathogenesis.

Home fortification of foods with multiple micronutrient powders for health and nutrition in children under two years of age

BACKGROUND

Vitamin and mineral deficiencies, particularly those of iron, vitamin A, and zinc, affect more than two billion people worldwide. Young children are highly vulnerable because of rapid growth and inadequate dietary practices. Multiple micronutrient powders (MNPs) are single-dose packets containing multiple vitamins and minerals in powder form, which are mixed into any semi-solid food for children six months of age or older. The use of MNPs for home or point-of-use fortification of complementary foods has been proposed as an intervention for improving micronutrient intake in children under two years of age. In 2014, MNP interventions were implemented in 43 countries and reached over three million children. This review updates a previous Cochrane Review, which has become out-of-date.

OBJECTIVES

To assess the effects and safety of home (point-of-use) fortification of foods with MNPs on nutrition, health, and developmental outcomes in children under two years of age. For the purposes of this review, home fortification with MNP refers to the addition of powders containing vitamins and minerals to semi-solid foods immediately before consumption. This can be done at home or at any other place that meals are consumed (e.g. schools, refugee camps). For this reason, MNPs are also referred to as point-of-use fortification.

SEARCH METHODS

We searched the following databases up to July 2019: CENTRAL, MEDLINE, Embase, and eight other databases. We also searched four trials registers, contacted relevant organisations and authors of included studies to identify any ongoing or unpublished studies, and searched the reference lists of included studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs with individual randomisation or cluster-randomisation. Participants were infants and young children aged 6 to 23 months at the time of intervention, with no identified specific health problems. The intervention consisted of consumption of food fortified at the point of use with MNP formulated with at least iron, zinc, and vitamin A, compared with placebo, no intervention, or use of iron-containing supplements, which is standard practice.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies, and assessed the risk of bias of included studies. We reported categorical outcomes as risk ratios (RRs) or odds ratios (ORs), with 95% confidence intervals (CIs), and continuous outcomes as mean differences (MDs) and 95% CIs. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 29 studies (33,147 children) conducted in low- and middle-income countries in Asia, Africa, Latin America, and the Caribbean, where anaemia is a public health problem. Twenty-six studies with 27,051 children contributed data. The interventions lasted between 2 and 44 months, and the powder formulations contained between 5 and 22 nutrients. Among the 26 studies contributing data, 24 studies (26,486 children) compared the use of MNP versus no intervention or placebo; the two remaining studies compared the use of MNP versus an iron-only supplement (iron drops) given daily. The main outcomes of interest were related to anaemia and iron status. We assessed most of the included studies at low risk of selection and attrition bias. We considered some studies to be at high risk of performance and detection bias due to lack of blinding. Most studies were funded by government programmes or foundations; only two were funded by industry. Home fortification with MNP, compared with no intervention or placebo, reduced the risk of anaemia in infants and young children by 18% (RR 0.82, 95% CI 0.76 to 0.90; 16 studies; 9927 children; moderate-certainty evidence) and iron deficiency by 53% (RR 0.47, 95% CI 0.39 to 0.56; 7 studies; 1634 children; high-certainty evidence). Children receiving MNP had higher haemoglobin concentrations (MD 2.74 g/L, 95% CI 1.95 to 3.53; 20 studies; 10,509 children; low-certainty evidence) and higher iron status (MD 12.93 μg/L, 95% CI 7.41 to 18.45; 7 studies; 2612 children; moderate-certainty evidence) at follow-up compared with children receiving the control intervention. We did not find an effect on weight-for-age (MD 0.02, 95% CI -0.03 to 0.07; 10 studies; 9287 children; moderate-certainty evidence). Few studies reported morbidity outcomes (three to five studies each outcome) and definitions varied, but MNP did not increase diarrhoea, upper respiratory infection, malaria, or all-cause morbidity. In comparison with daily iron supplementation, the use of MNP produced similar results for anaemia (RR 0.89, 95% CI 0.58 to 1.39; 1 study; 145 children; low-certainty evidence) and haemoglobin concentrations (MD -2.81 g/L, 95% CI -10.84 to 5.22; 2 studies; 278 children; very low-certainty evidence) but less diarrhoea (RR 0.52, 95% CI 0.38 to 0.72; 1 study; 262 children; low-certainty of evidence). However, given the limited quantity of data, these results should be interpreted cautiously. Reporting of death was infrequent, although no trials reported deaths attributable to the intervention. Information on side effects and morbidity, including malaria and diarrhoea, was scarce. It appears that use of MNP is efficacious among infants and young children aged 6 to 23 months who are living in settings with different prevalences of anaemia and malaria endemicity, regardless of intervention duration. MNP intake adherence was variable and in some cases comparable to that achieved in infants and young children receiving standard iron supplements as drops or syrups.

AUTHORS' CONCLUSIONS

Home fortification of foods with MNP is an effective intervention for reducing anaemia and iron deficiency in children younger than two years of age. Providing MNP is better than providing no intervention or placebo and may be comparable to using daily iron supplementation. The benefits of this intervention as a child survival strategy or for developmental outcomes are unclear. Further investigation of morbidity outcomes, including malaria and diarrhoea, is needed. MNP intake adherence was variable and in some cases comparable to that achieved in infants and young children receiving standard iron supplements as drops or syrups.

Impact of Daily Preventive Zinc or Therapeutic Zinc Supplementation for Diarrhea on Plasma Biomarkers of Environmental Enteric Dysfunction among Rural Laotian Children: A Randomized Controlled Trial

Environmental enteric dysfunction (EED) may be ameliorated by zinc supplementation. The objective of this study was to investigate the impact of different forms of zinc supplementation on biomarkers of EED (i.e., plasma citrulline, kynurenine, and tryptophan concentrations and the kynurenine:tryptophan [KT] ratio) among young Laotian children. In a double-blind randomized controlled trial, 3,407 children aged 6-23 months were randomized into one of four groups: daily preventive zinc dispersible tablets (PZ; 7 mg zinc), daily multiple micronutrient powders (MNP; 10 mg zinc, 6 mg iron, and 13 other micronutrients), therapeutic zinc supplements for diarrhea treatment (TZ; 20 mg/day for 10 days), or daily placebo powder, and followed up for ∼36 weeks. Plasma samples at baseline and endline for 359 children were analyzed for citrulline, kynurenine, and tryptophan concentrations. At baseline, the prevalence of stunting and zinc deficiency was 37% and 76.5%, respectively. The mean plasma citrulline, kynurenine, and tryptophan concentrations were 24.6 ± 5.4 µmol/L, 3.27 ± 0.83 µmol/L, and 72.3 ± 12.9 µmol/L, respectively; the mean KT ratio (×1,000) was 45.9 ± 12.0. At endline, neither plasma citrulline, kynurenine, or tryptophan concentrations, nor the KT ratio differed among intervention groups (P > 0.05). In this population, PZ, MNP, and TZ had no overall effect on plasma concentrations of citrulline, kynurenine, and tryptophan, or the KT ratio. The need remains to better understand the etiology of EED, and the development of biomarkers to diagnose EED and evaluate the impact of interventions.

Effects of improved water, sanitation, and hygiene and improved complementary feeding on environmental enteric dysfunction in children in rural Zimbabwe: A cluster-randomized controlled trial

BACKGROUND

Environmental enteric dysfunction (EED) may be an important modifiable cause of child stunting. We described the evolution of EED biomarkers from birth to 18 months in rural Zimbabwe and tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF), on EED.

METHODOLOGY AND FINDINGS

The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial was a 2x2 factorial cluster-randomised trial of improved IYCF and improved WASH on child stunting and anaemia at 18 months of age. 1169 infants born to HIV-negative mothers provided plasma and faecal specimens at 1, 3, 6, 12, and 18 months of age. We measured EED biomarkers that reflect all domains of the hypothesized pathological pathway. Markers of intestinal permeability and intestinal inflammation declined over time, while markers of microbial translocation and systemic inflammation increased between 1-18 months. Markers of intestinal damage (I-FABP) and repair (REG-1β) mirrored each other, and citrulline (a marker of intestinal epithelial mass) increased from 6 months of age, suggesting dynamic epithelial turnover and regeneration in response to enteric insults. We observed few effects of IYCF and WASH on EED after adjustment for multiple comparisons. The WASH intervention decreased plasma IGF-1 at 3 months (β:0.89, 95%CI:0.81,0.98) and plasma kynurenine at 12 months (β: 0.92, 95%CI:0.87,0.97), and increased plasma IGF-1 at 18 months (β:1.15, 95%CI:1.05,1.25), but these small WASH effects did not translate into improved growth.

CONCLUSIONS

Overall, we observed dynamic trends in EED but few effects of IYCF or WASH on biomarkers during the first 18 months after birth, suggesting that these interventions did not impact EED. Transformative WASH interventions are required to prevent or ameliorate EED in low-income settings.

Mass deworming for improving health and cognition of children in endemic helminth areas: A systematic review and individual participant data network meta-analysis

Background

Soil transmitted (or intestinal) helminths and schistosomes affect millions of children worldwide.

Objectives

To use individual participant data network meta-analysis (NMA) to explore the effects of different types and frequency of deworming drugs on anaemia, cognition and growth across potential effect modifiers.

Search Methods

We developed a search strategy with an information scientist to search MEDLINE, CINAHL, LILACS, Embase, the Cochrane Library, Econlit, Internet Documents in Economics Access Service (IDEAS), Public Affairs Information Service (PAIS), Social Services Abstracts, Global Health CABI and CAB Abstracts up to March 27, 2018. We also searched grey literature, websites, contacted authors and screened references of relevant systematic reviews.

Selection Criteria

We included randomised and quasirandomised deworming trials in children for deworming compared to placebo or other interventions with data on baseline infection.

Data Collection and Analysis

We conducted NMA with individual participant data (IPD), using a frequentist approach for random-effects NMA. The covariates were: age, sex, weight, height, haemoglobin and infection intensity. The effect estimate chosen was the mean difference for the continuous outcome of interest.

Results

We received data from 19 randomized controlled trials with 31,945 participants. Overall risk of bias was low. There were no statistically significant subgroup effects across any of the potential effect modifiers. However, analyses showed that there may be greater effects on weight for moderate to heavily infected children (very low certainty evidence).

Authors' Conclusions

This analysis reinforces the case against mass deworming at a population-level, finding little effect on nutritional status or cognition. However, children with heavier intensity infections may benefit more. We urge the global community to adopt calls to make data available in open repositories to facilitate IPD analyses such as this, which aim to assess effects for the most vulnerable individuals.

Tryptophan, glutamine, leucine, and micronutrient supplementation improves environmental enteropathy in Zambian adults: a randomized controlled trial

BACKGROUND

Environmental enteropathy (EE) refers to villus blunting, reduced absorption, and microbial translocation in children and adults in tropical or deprived residential areas. In previous work we observed an effect of micronutrients on villus height (VH).

OBJECTIVE

We aimed to determine, in a randomized controlled trial, if amino acid (AA) or multiple micronutrient (MM) supplementation can improve intestinal structure or barrier dysfunction in Zambian adults with EE.

METHODS

AA (tryptophan, leucine, and glutamine) and/or MM supplements were given for 16 wk in a 2 × 2 factorial comparison against placebo. Primary outcomes were changes in VH, in vivo small intestinal barrier dysfunction assessed by confocal laser endomicroscopy (CLE), and mechanistic (or mammalian) target of rapamycin complex 1 (MTORC1) nutrient responsiveness in lamina propria CD4+ lymphocytes.

RESULTS

Over 16 wk AA, but not MM, supplementation increased VH by 16% (34.5 μm) compared with placebo (P = 0.04). Fluorescein leak, measured by CLE, improved only in those allocated to both AA and MM supplementation. No effect was seen on MTORC1 activation, but posttreatment MTORC1 and VH were correlated (ρ = 0.51; P = 0.001), and change in MTORC1 was correlated with change in VH in the placebo group (ρ = 0.63; P = 0.03). In secondary analyses no effect was observed on biomarkers of microbial translocation. Metabolomic analyses suggest alterations in a number of microbial- and host-derived metabolites including the leucine metabolite β-hydroxy-β-methylbutyrate, which was increased by AA supplementation and correlated with VH.

CONCLUSIONS

In this phase 2 trial, AA supplementation protected against a decline in VH over the supplementation period, and improved barrier function when combined with micronutrients. Leucine and MTORC1 metabolism may be involved in the mechanism of effect. This trial was registered at www.pactr.org as PACTR201505001104412.

Rice bran supplementation modulates growth, microbiota and metabolome in weaning infants: a clinical trial in Nicaragua and Mali

Rice bran supplementation provides nutrients, prebiotics and phytochemicals that enhance gut immunity, reduce enteric pathogens and diarrhea, and warrants attention for improvement of environmental enteric dysfunction (EED) in children. EED is a subclinical condition associated with stunting due to impaired nutrient absorption. This study investigated the effects of rice bran supplementation on weight for age and length for age z-scores (WAZ, LAZ), EED stool biomarkers, as well as microbiota and metabolome signatures in weaning infants from 6 to 12 months old that reside in Nicaragua and Mali. Healthy infants were randomized to a control (no intervention) or a rice bran group that received daily supplementation with increasing doses at each month (1–5 g/day). Stool microbiota were characterized using 16S rDNA amplicon sequencing. Stool metabolomes were analyzed using ultra-high-performance liquid-chromatography tandem mass-spectrometry. Statistical comparisons were completed at 6, 8, and 12 months of age. Daily consumption of rice bran was safe and feasible to support changes in LAZ from 6–8 and 8–12 months of age in Nicaragua and Mali infants when compared to control. WAZ was significantly improved only for Mali infants at 8 and 12 months. Mali and Nicaraguan infants showed major differences in the overall gut microbiota and metabolome composition and structure at baseline, and thus each country cohort demonstrated distinct microbial and metabolite profile responses to rice bran supplementation when compared to control. Rice bran is a practical dietary intervention strategy that merits development in rice-growing regions that have a high prevalence of growth stunting due to malnutrition and diarrheal diseases. Rice is grown as a staple food, and the bran is used as animal feed or wasted in many low- and middle-income countries where EED and stunting is prevalent.

Public health deworming programmes for soil-transmitted helminths in children living in endemic areas

BACKGROUND

The World Health Organization (WHO) recommends treating all school children at regular intervals with deworming drugs in areas where helminth infection is common. Global advocacy organizations claim routine deworming has substantive health and societal effects beyond the removal of worms. In this update of the 2015 edition we included six new trials, additional data from included trials, and addressed comments and criticisms.

OBJECTIVES

To summarize the effects of public health programmes to regularly treat all children with deworming drugs on child growth, haemoglobin, cognition, school attendance, school performance, physical fitness, and mortality.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; Embase; LILACS; the metaRegister of Controlled Trials (mRCT); reference lists; and registers of ongoing and completed trials up to 19 September 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs that compared deworming drugs for soil-transmitted helminths (STHs) with placebo or no treatment in children aged 16 years or less, reporting on weight, height, haemoglobin, and formal tests of cognition. We also sought data on other measures of growth, school attendance, school performance, physical fitness, and mortality.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials for inclusion, risk of bias, and extracted data. We analysed continuous data using the mean difference (MD) with 95% confidence intervals (CIs). Where data were missing, we contacted trial authors. We stratified the analysis based on the background burden of STH infection. We used outcomes at time of longest follow-up. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We identified 51 trials, including 10 cluster-RCTs, that met the inclusion criteria. One trial evaluating mortality included over one million children, and the remaining 50 trials included a total of 84,336 participants. Twenty-four trials were in populations categorized as high burden, including nine trials in children selected because they were helminth-stool positive; 18 with intermediate burden; and nine as low burden.First or single dose of deworming drugsFourteen trials reported on weight after a single dose of deworming drugs (4970 participants, 14 RCTs). The effects were variable. There was little or no effect in studies conducted in low and intermediate worm burden groups. In the high-burden group, there was little or no effect in most studies, except for a large effect detected from one study area in Kenya reported in two trials carried out over 30 years ago. These trials result in qualitative heterogeneity and uncertainty in the meta-analysis across all studies (I2 statistic = 90%), with GRADE assessment assessed as very low-certainty, which means we do not know if a first dose or single dose of deworming impacts on weight.For height, most studies showed little or no effect after a single dose, with one of the two trials in Kenya from 30 years ago showing a large average difference (2621 participants, 10 trials, low-certainty evidence). Single dose probably had no effect on average haemoglobin (MD 0.10 g/dL, 95% CI 0.03 lower to 0.22 higher; 1252 participants, five trials, moderate-certainty evidence), or on average cognition (1596 participants, five trials, low-certainty evidence). The data are insufficient to know if there is an effect on school attendance and performance (304 participants, one trial, low-certainty evidence), or on physical fitness (280 participants, three trials, very low-certainty evidence). No trials reported on mortality.Multiple doses of deworming drugsThe effect of regularly treating children with deworming drugs given every three to six months on weight was reported in 18 trials, with follow-up times of between six months and three years; there was little or no effect on average weight in all but two trials, irrespective of worm prevalence-intensity. The two trials with large average weight gain included one in the high burden area in Kenya carried out over 30 years ago, and one study from India in a low prevalence area where subsequent studies in the same area did not show an effect. This heterogeneity causes uncertainty in any meta-analysis (I2 = 78%). Post-hoc analysis excluding trials published prior to 2000 gave an estimate of average difference in weight gain of 0.02 kg (95%CI from 0.04 kg loss to 0.08 gain, I2 = 0%). Thus we conclude that we do not know if repeated doses of deworming drugs impact on average weight, with a fewer older studies showing large gains, and studies since 2000 showing little or no average gain.Regular treatment probably had little or no effect on the following parameters: average height (MD 0.02 cm higher, 95% CI 0.09 lower to 0.13 cm higher; 13,700 participants, 13 trials, moderate-certainty evidence); average haemoglobin (MD 0.01 g/dL lower; 95% CI 0.05 g/dL lower to 0.07 g/dL higher; 5498 participants, nine trials, moderate-certainty evidence); formal tests of cognition (35,394 participants, 8 trials, moderate-certainty evidence); school performance (34,967 participants, four trials, moderate-certainty evidence). The evidence assessing an effect on school attendance is inconsistent, and at risk of bias (mean attendance 2% higher, 95% CI 5% lower to 8% higher; 20,650 participants, three trials, very low-certainty evidence). No trials reported on physical fitness. No effect was shown on mortality (1,005,135 participants, three trials, low-certainty evidence).

AUTHORS' CONCLUSIONS

Public health programmes to regularly treat all children with deworming drugs do not appear to improve height, haemoglobin, cognition, school performance, or mortality. We do not know if there is an effect on school attendance, since the evidence is inconsistent and at risk of bias, and there is insufficient data on physical fitness. Studies conducted in two settings over 20 years ago showed large effects on weight gain, but this is not a finding in more recent, larger studies. We would caution against selecting only the evidence from these older studies as a rationale for contemporary mass treatment programmes as this ignores the recent studies that have not shown benefit.The conclusions of the 2015 edition have not changed in this update.

Markers of Systemic Inflammation and Environmental Enteric Dysfunction Are Not Reduced by Zinc or Multivitamins in Tanzanian Infants: A Randomized, Placebo-Controlled Trial

OBJECTIVE

To examine whether daily zinc and/or multivitamin supplementation reduce biomarkers of environmental enteric dysfunction (EED), systemic inflammation, or markers of growth in a sample of infants from Dar es Salaam, Tanzania.

STUDY DESIGN

Subgroup analysis of infants participating in a randomized, double-blind, placebo-controlled trial received daily oral supplementation of zinc, multivitamins, zinc + multivitamins, or placebo for 18 months starting at 6 weeks of age. EED (anti-flagellin and anti-lipopolysaccharide immunoglobulins), systemic inflammation (C-reactive protein and alpha-1-acid glycoprotein), and growth biomarkers (insulin-like growth factor-1 and insulin-like growth factor binding protein-3) were measured via enzyme-linked immunosorbent assay in a subsample of 590 infants at 6 weeks and 6 months of age. EED biomarkers also were measured in 162 infants at 12 months of age.

RESULTS

With the exception of anti-lipopolysaccharide IgG concentrations, which were significantly greater in infants who received multivitamins compared with those who did not (1.41 ± 0.61 vs 1.26 ± 0.65, P = .006), and insulin-like growth factor binding protein-3 concentrations, which were significantly lower in children who received zinc compared with those who did not (981.13 ± 297.59 vs 1019.10 ± 333.01, P = .03), at 6 months of age, we did not observe any significant treatment effects of zinc or multivitamins on EED, systemic inflammation, or growth biomarkers.

CONCLUSIONS

Neither zinc nor multivitamin supplementation ameliorated markers of EED or systemic inflammation during infancy. Other interventions should be prioritized for future trials.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00421668.

Linear growth failure induced by systemic inflammation inhibiting IGF-1/IGFBP axis in rats with asymptomatic colitis

Background

Children in poor areas show significant growth retardation that does not improve with an adequate supply of energy and nutrients, which may be related to asymptomatic intestinal infection caused by poor sanitation. Our objective was to explore the mechanism of intestinal inflammation inhibiting growth in the setting of asymptomatic colitis.

Methods

Forty-eight 3-week-old Wistar rats were randomly divided into three groups: the control group, colitis group (with asymptomatic colitis induced by 2.5% trinitrobenzenesulphonic acid) and pair-fed group (daily food intake matched to the pair in the colitis group). The linear growth was assessed, and the plasma levels of hormone and systemic cytokines were detected and compared by independent two-sample t-test or one-way ANOVA among groups.

Results

At d5, the increases in the body length of the control, colitis and pair-fed groups were 1.65 ± 0.34 cm, 1.10 ± 0.30 cm and 1.38 ± 0.26 cm, respectively, and the increase in the body length in the colitis group was significantly less than that in the control group (P < 0.05). There were significant differences in the levels of hormone and cytokines among three groups (P < 0.05). Compared with the control group, rats in the colitis group exhibited linear growth failure, as well as higher expression of calprotectin, tumour necrosis factor-α, interleukin-6 and insulin-like growth factor binding protein 2, lower insulin-like growth factor-1 and insulin-like growth factor binding protein 3, and lower expression of nuclear factor kappa B in hepatocytes.

Conclusions

In addition to undernutrition, the systemic inflammatory response caused by asymptomatic colitis may inhibit the linear growth of rats by its influence on the insulin-like growth factor/insulin-like growth factor binding protein axis.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-1023-z) contains supplementary material, which is available to authorized users.

Plasma Fibroblast Growth Factor 21 Is Associated with Subsequent Growth in a Cohort of Underweight Children in Bangladesh

BACKGROUND

Current nutritional intervention strategies have not proven effective in improving childhood ponderal and linear growth in underweight and stunted children. Novel markers are needed to classify children who are likely to respond to available interventions and to identify those requiring additional interventions. Fibroblast Growth Factor 21 (FGF21), an endocrine hormone that regulates metabolism and growth during periods of reduced protein intake, may be useful in this context.

OBJECTIVES

We aimed to determine the associations between plasma FGF21 concentrations and subsequent growth, and the association between change in FGF21 concentrations and concurrent growth, in children receiving nutritional supplementation.

METHODS

A total of 120 children between ages 6 and 13 mo with weight-for-age z score (WAZ) between -3 and -2 were enrolled from an urban slum in Dhaka, Bangladesh. Children received 376-kcal feeding supplements daily for 5 mo and were followed for 5 additional mo. FGF21 was measured in plasma collected at enrollment and month 5. FGF21 values that fell above the 90th percentile of baseline concentrations (1056.5 pg/mL) were considered high. Linear regression was used to examine the association between baseline FGF21 status and 5-mo change in WAZ and length-for-age z score (LAZ), and the association between 5-mo change in FGF21 and concurrent WAZ and LAZ change.

RESULTS

The median baseline FGF21 concentration was 241.4 pg/mL (IQR: 111.7, 451.3 pg/mL). On average, children with high baseline FGF21 gained 0.58 WAZ (95% CI: 0.28, 0.88) and 0.54 LAZ (95% CI: 0.23, 0.84) more during supplementation than those with low values. Change in FGF21 concentration during supplementation was negatively associated with change in WAZ (-0.48; 95% CI: -0.67, -0.29) and LAZ (-0.31; 95% CI: -0.52, -0.11).

CONCLUSIONS

FGF21 may be a useful marker of growth faltering and may allow identification of children who are more or less likely to respond to nutritional supplementation. This trial was registered at clinicaltrials.gov as NCT02441426.

Supplementation With Lactoferrin and Lysozyme Ameliorates Environmental Enteric Dysfunction: A Double-Blind, Randomized, Placebo-Controlled Trial

INTRODUCTION

Environmental enteric dysfunction (EED) predisposes children throughout the developing world to high rates of systemic exposure to enteric pathogens and stunting. Effective interventions that treat or prevent EED may help children achieve their full physical and cognitive potential. The objective of this study is to test whether 2 components of breast milk would improve a biomarker of EED and linear growth during the second year of life.

METHODS

A prospective, randomized, double-blind, placebo-controlled clinical trial among children aged 12-23 months was conducted in rural Malawi. The experimental group received a daily supplement of 1.5 g of lactoferrin and 0.2 g of lysozyme for 16 weeks. The primary outcome was an improvement in EED, as measured by the change in the percentage of ingested lactulose excreted into the urine (Δ%L).

RESULTS

Among 214 children who completed the study, there was a significant difference in Δ%L between the control and experimental groups over 8 weeks (an increase of 0.23% vs 0.14%, respectively; P = 0.04). However, this relative improvement was not as strongly sustained over the full 16 weeks of the study (an increase of 0.16% vs 0.11%, respectively; P = 0.17). No difference in linear growth over this short period was observed. The experimental intervention group had significantly lower rates of hospitalization and the development of acute malnutrition during the course of the study (2.5% vs 10.3%, relative risk 0.25; P < 0.02).

DISCUSSION

Supplementation with lactoferrin and lysozyme in a population of agrarian children during the second year of life has a beneficial effect on gut health. This intervention also protected against hospitalization and the development of acute malnutrition, a finding with a significant clinical and public health importance. This finding should be pursued in larger studies with longer follow-up and optimized dosing.

Consumption of Animal-Source Protein is Associated with Improved Height-for-Age z Scores in Rural Malawian Children Aged 12⁻36 Months

Linear growth faltering, caused by insufficient diet, recurrent infections and environmental enteric dysfunction (EED), continues to plague young children in low- and middle-income countries (LMICs). Diets in LMICs are primarily plant based, and thus have poor-quality protein and low levels of essential micronutrients. The aim of this study was to assess the association of the type and protein quality of food consumed with stunting, EED and acute malnutrition in children aged 6⁻36 months in Limera and Masenjere, two rural Southern Malawian communities. This is a secondary analysis of two randomized controlled trials that tested the effects of common bean and cowpea flour on stunting in children aged 6⁻36 months. We used data from two interactive 24-h dietary recalls conducted 12 weeks after enrolment into each trial. Food intakes were compared between the regions using Chi-square and Student's t-test. There were 355 children that participated in the dietary recalls. The diets of children were of poor quality, but the children from Limera consumed more fish (54% vs. 35%, p = 0.009) and more bioavailable protein (26.0 ± 10.3 g/day vs. 23.1 ± 8.1 g/day, p = 0.018, respectively) than children in Masenjere. Food type and protein quality were not associated with any of the outcomes except an association between animal protein consumption and improvement in height-for-age z scores in children aged 12⁻36 months (p = 0.047). These findings support the notion that animal-source food (ASF) consumption in this vulnerable population promotes linear growth.

Nutrient intake and environmental enteric dysfunction among Nepalese children 9-24 months old-the MAL-ED birth cohort study

BACKGROUND

Nutrient deficiencies limit the growth and turnover of intestinal mucosa, but studies assessing whether specific nutrients protect against or improve environmental enteric dysfunction (EED) are scarce. We aimed to investigate associations between nutrient intake and EED assessed by lactulose:mannitol (L:M) ratio, anti-1-antitrypsin, myeloperoxidase (MPO), and neopterin (NEO) among children 9-24 months in Bhaktapur, Nepal.

METHODS

Among 231 included children, nutrient intake was assessed monthly by 24 h recalls, and 3-month usual intake was estimated using Multiple Source Method. Associations between nutrient intake and L:M ratio (measured at 15 months) were assessed using multiple linear regression, while associations between nutrient intake and fecal markers (measured quarterly) were assessed using Generalized Estimating Equations (GEE) models.

RESULTS

We found that associations between nutrient intake from complementary food and L:M ratio, alpha-1-antitrypsin (AAT), MPO and NEO were generally negative but weak. The only significant associations between nutrient intake (potassium, magnesium, phosphorous, folate, and vitamin C) and markers for intestinal inflammation were found for MPO.

CONCLUSION

Negative but weak associations between nutrient intake and markers of intestinal inflammation were found. Significant associations between several nutrients and MPO might merit further investigation.

Pathophysiology of environmental enteric dysfunction and its impact on oral vaccine efficacy

Environmental enteric dysfunction (EED) refers to a subclinical disorder of intestinal function common in tropical countries and in settings of poverty and economic disadvantage. The enteropathy that underlies this syndrome is characterized by mucosal inflammation and villus blunting mediated by T cell activation. Epithelial cell disruption and microbial translocation drive systemic inflammation. EED in young children is associated geographically with growth failure, malnutrition, and greatly impaired responses to oral vaccines, notably rotavirus and poliovirus vaccines. In this review, we describe the pathophysiology of EED and examine the evidence linking EED and oral vaccine failure. This evidence is far from conclusive. Although our understanding of EED is still sketchy, there is limited evidence of disturbed innate immunity, B cell disturbances including aggregation into lymphoid follicles, and autoantibody generation. Pathways of T cell activation and the possibility of dendritic cell anergy, which could help explain oral vaccine failure, require further work.

Identifying the etiology and pathophysiology underlying stunting and environmental enteropathy: study protocol of the AFRIBIOTA project

BACKGROUND

Globally one out of four children under 5 years is affected by linear growth delay (stunting). This syndrome has severe long-term sequelae including increased risk of illness and mortality and delayed psychomotor development. Stunting is a syndrome that is linked to poor nutrition and repeated infections. To date, the treatment of stunted children is challenging as the underlying etiology and pathophysiological mechanisms remain elusive. We hypothesize that pediatric environmental enteropathy (PEE), a chronic inflammation of the small intestine, plays a major role in the pathophysiology of stunting, failure of nutritional interventions and diminished response to oral vaccines, potentially via changes in the composition of the pro- and eukaryotic intestinal communities. The main objective of AFRIBIOTA is to describe the intestinal dysbiosis observed in the context of stunting and to link it to PEE. Secondary objectives include the identification of the broader socio-economic environment and biological and environmental risk factors for stunting and PEE as well as the testing of a set of easy-to-use candidate biomarkers for PEE. We also assess host outcomes including mucosal and systemic immunity and psychomotor development. This article describes the rationale and study protocol of the AFRIBIOTA project.

METHODS

AFRIBIOTA is a case-control study for stunting recruiting children in Bangui, Central African Republic and in Antananarivo, Madagascar. In each country, 460 children aged 2-5 years with no overt signs of gastrointestinal disease are recruited (260 with no growth delay, 100 moderately stunted and 100 severely stunted). We compare the intestinal microbiota composition (gastric and small intestinal aspirates; feces), the mucosal and systemic immune status and the psychomotor development of children with stunting and/or PEE compared to non-stunted controls. We also perform anthropological and epidemiological investigations of the children's broader living conditions and assess risk factors using a standardized questionnaire.

DISCUSSION

To date, the pathophysiology and risk factors of stunting and PEE have been insufficiently investigated. AFRIBIOTA will add new insights into the pathophysiology underlying stunting and PEE and in doing so will enable implementation of new biomarkers and design of evidence-based treatment strategies for these two syndromes.

Exploring the relationship between environmental enteric dysfunction and oral vaccine responses

Oral vaccines significantly underperform in low-income countries. One possible contributory factor is environmental enteric dysfunction (EED), a subclinical disorder of small intestinal structure and function among children living in poverty. Here, we review studies describing oral vaccine responses and EED. We identified eight studies evaluating EED and oral vaccine responses. There was substantial heterogeneity in study design and few consistent trends emerged. Four studies reported a negative association between EED and oral vaccine responses; two showed no significant association; and two described a positive correlation. Current evidence is therefore insufficient to determine whether EED contributes to oral vaccine underperformance. We identify roadblocks in the field and future research needs, including carefully designed studies those can investigate this hypothesis further.

Dietary diversity and anthropometric status and failure among infants and young children in Sri Lanka

OBJECTIVES

We investigate the association between child dietary diversity and anthropometric status and failure in Sri Lanka while accounting for other child and household factors by employing multivariable logistic and linear regression analyses.

METHODS

Using a nationally representative survey of children ages 6 mo to 59 mo, child dietary diversity was based on the 24-h recall of a child's food intake across seven food groups. The minimum dietary diversity was a score of four or above. Anthropometric status (i.e., height for age (HAZ), weight for age, and weight for height z-scores) and failure (i.e., stunting, wasting, and underweight) were calculated.

RESULTS

The prevalence of stunting, wasting, and underweight was 15%, 21%, and 26%, respectively. The prevalence of inadequate dietary diversity was 9%. Child dietary diversity was positively associated with HAZ (b = 0.02; standard error = 0.01; P = 0.04) but not with any indicator of anthropometric failure. However, low birth weight, wealth, and location were strong risk factors for anthropometric status and failure. Analyses stratified by child age indicated that dietary diversity was positively associated with anthropometric status for children ages 24 mo to 59 mo (HAZ: b = 0.03; standard error = 0.01; P = 0.02). Mixed associations were found for children ages 6 mo to 12 mo and there were no associations for children ages 12 mo to 24 mo.

CONCLUSIONS

Child dietary diversity predicted anthropometric status among children ages ≥24 mo. Interventions to address both proximal and distal risk factors for anthropometric status may be necessary in Sri Lanka to reduce anthropometric failure among infants and young children.

Additional Common Bean in the Diet of Malawian Children Does Not Affect Linear Growth, but Reduces Intestinal Permeability

Background

Chronic malnutrition, as manifested by linear growth faltering, is pervasive among rural African children. Improvements in complementary feeding may decrease the burden of environmental enteric dysfunction (EED) and thus improve growth in children during the critical first 1000 d of development.

Objective

We tested the hypothesis that systematically including common bean or cowpea into complementary feeding would reduce EED and growth faltering among children in rural Malawi.

Methods

This was a double-blind clinical trial in which children 12-23 mo of age were randomly assigned to receive complementary feeding with 1 of 3 foods: roasted cowpea or common bean flour, or an isoenergetic amount of corn-soy blend as a control food for 48 wk. Children aged 12-23 mo received 155 kcal/d and thereafter until 35 mo received 200 kcal/d. The primary outcomes were change in length-for-age z score (LAZ) and improvements in a biomarker of EED, the percentage of lactulose (%L) excreted as part of the lactulose:mannitol dual-sugar absorption test. Anthropometric measurements and urinary %L excretion were compared between the 2 intervention groups and the control group separately with the use of linear mixed model analyses for repeated measures.

Results

A total of 331 children completed the clinical trial. Compliance with the study interventions was excellent, with >90% of the intervention flour consumed as intended. No significant effects on LAZ, change in LAZ, or weight-for-length z score were observed due to either intervention legume, compared to the control. %L was reduced with common bean consumption (effect estimate was -0.07 percentage points of lactulose, P = 0.0007). The lactulose:mannitol test was not affected by the legume intervention.

Conclusion

The addition of common bean to complementary feeding of rural Malawian children during the second year of life led to an improvement in a biomarker of gut health, although this did not directly translate into improved linear growth. This trial was registered at clinicaltrials.gov as NCT02472301.

Environmental enteric dysfunction pathways and child stunting: A systematic review

BACKGROUND

Environmental enteric dysfunction (EED) is commonly defined as an acquired subclinical disorder of the small intestine, characterized by villous atrophy and crypt hyperplasia. EED has been proposed to underlie stunted growth among children in developing countries. A collection of biomarkers, organized into distinct domains, has been used to measure different aspects of EED. Here, we examine whether these hypothesized relationships, among EED domains and between each domain and stunting, are supported by data from recent studies.

METHODOLOGY

A systematic literature search was conducted using PubMed, MEDLINE, EMBASE, Web of Science, and CINAHL between January 1, 2010 and April 20, 2017. Information on study objective, design, population, location, biomarkers, and results were recorded, as well as qualitative and quantitative definitions of EED. Biomarkers were organized into five EED domains, and the number of studies that support or do not support relationships among domains and between each domain with stunting were summarized.

RESULTS

There was little evidence to support the pathway from intestinal permeability to microbial translocation and from microbial translocation to stunting, but stronger support existed for the link between intestinal inflammation and systemic inflammation and for intestinal inflammation and stunting. There was conflicting evidence for the pathways from intestinal damage to intestinal permeability and intestinal damage to stunting.

CONCLUSIONS

These results suggest that certain EED biomarkers may require reconsideration, particularly those most difficult to measure, such as microbial translocation and intestinal permeability. We discuss several issues with currently used biomarkers and recommend further analysis of pathogen-induced changes to the intestinal microbiota as a pathway leading to stunting.

Lactoferrin and lysozyme to reduce environmental enteric dysfunction and stunting in Malawian children: study protocol for a randomized controlled trial

Background

Chronic childhood malnutrition, as manifested by stunted linear growth, remains a persistent barrier to optimal child growth and societal development. Environmental enteric dysfunction (EED) is a significant underlying factor in the causal pathway to stunting, delayed cognitive development, and ultimately morbidity and mortality. Effective therapies against EED and stunting are lacking and further clinical trials are warranted to effectively identify and operationalize interventions.

Methods/design

A prospective randomized placebo-controlled parallel-group randomized controlled trial will be conducted to determine if a daily supplement of lactoferrin and lysozyme, two important proteins found in breast milk, can decrease the burden of EED and stunting in rural Malawian children aged 12–23 months old. The intervention and control groups will have a sample size of 86 subjects each. All field and laboratory researchers will be blinded to the assigned intervention group, as will the subjects and their caregivers. The percentage of ingested lactulose excreted in the urine (Δ%L) after 4 h will be used as the biomarker for EED and linear growth as the measure of chronic malnutrition (stunting). The primary outcomes of interest will be change in Δ%L from baseline to 8 weeks and to 16 weeks. Intention-to-treat analyses will be used.

Discussion

A rigorous clinical trial design will be used to assess the biologically plausible use of lactoferrin and lysozyme as dietary supplements for children at high risk for EED. If proven effective, these safe proteins may serve to markedly reduce the burden of childhood malnutrition and improve survival.

Trial Registration

Clinicaltrials.gov, NCT02925026. Registered on 4 October 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2278-8) contains supplementary material, which is available to authorized users.

The Nutrient and Metabolite Profile of 3 Complementary Legume Foods with Potential to Improve Gut Health in Rural Malawian Children

Background: Environmental enteric dysfunction (EED), frequently seen in rural Malawian children, causes chronic inflammation and increases the risk of stunting. Legumes may be beneficial for improving nutrition and reducing the risk of developing EED in weaning children. Objective: The objectives of this study were to determine the nutritional value, verify the food safety, and identify metabolite profiles of 3 legume-based complementary foods: common bean (CB), cowpea (CP), and traditional corn-soy blend (CSB). Methods: Foods were prepared by using local ingredients and analyzed for nutrient composition with the use of Association of Official Analytical Chemists (AOAC) standards (950.46, 991.43, 992.15, 996.06, and 991.36) for macro- and micronutrient proximate analysis. Food safety analysis was conducted in accordance with the Environmental Protection Agency (7471B) and AOAC (2008.02) standards. The metabolite composition of foods was determined with nontargeted ultra-performance LC-tandem mass spectrometry metabolomics. Results: All foods provided similar energy; CB and CP foods contained higher protein and dietary fiber contents than did the CSB food. Iron and zinc were highest in the CSB and CP foods, whereas CB and CP foods contained higher amounts of magnesium, phosphorus, and potassium. A total of 652 distinct metabolites were identified across the 3 foods, and 23, 14, and 36 metabolites were specific to the CSB, CB, and CP foods, respectively. Among the potential dietary biomarkers of intake to distinguish legume foods were pipecolic acid and oleanolic acid for CB; arabinose and serotonin for CSB; and quercetin and α- and γ-tocopherol acid for CP. No heavy metals were detected, and aflatoxin was measured only in the CSB (5.2 parts per billion). Conclusions: Legumes in the diet provide a rich source of protein, dietary fiber, essential micronutrients, and phytochemicals that may reduce EED. These food metabolite analyses identified potential dietary biomarkers of legume intake for stool, urine, and blood detection that can be used in future studies to assess the relation between the distinct legumes consumed and health outcomes. This trial was registered at clinicaltrials.gov as NCT02472262 and NCT02472301.

Tropical Enteropathies

PURPOSE OF REVIEW

The term 'tropical enteropathy' originated in observations in the 1960s that small intestinal morphology and function differed in the tropics from the norms found in temperate climates. It was subsequently shown that this enteropathy is more closely related to environmental conditions than latitude, and it was re-labelled 'environmental enteropathy'. It is now recognised that environmental enteropathy (also now called environmental enteric dysfunction) has implications for the health and linear growth of children in low- and middle-income countries, and it may underlie poor responses to oral vaccination in these countries. The purpose of this review is to define and clarify this enteropathy despite the confusing terminology it has attracted and to contrast it with other enteropathic states.

RECENT FINDINGS

Recent work has begun to demonstrate the nature of the mucosal lesion and the relationship with microbial translocation which is currently thought to link a failure of mucosal barrier function and the cascade of systemic inflammation which inhibits growth. The evidence is still correlative rather than definitive, but derives some additional support from animal models. There are some common features between environmental enteropathy and other enteropathies, but there are important differences also. The mechanism of the link between enteropathy and vaccine failure is not understood, and neither is it clear how the more severe form of enteropathy, which we refer to as malnutrition enteropathy, is driven by nutrient depletion and intestinal infection. Tropical enteropathies form a group of disorders which include environmental and nutritional enteropathies. The long-term health implications of these disorders for health in low-income countries are just being explored, but the scale of their effects is very large, with millions of people affected.