The effect of daily zinc and/or multivitamin supplements on early childhood development in Tanzania: results from a randomized controlled trial

Role of infant and early-childhood nutrition on gut inflammation, stunting, growth, and development in the African context: A narrative review

This article synthesizes the existing research evidence from Tanzania, a low- to middle-income country, highlighting the persistent issue of growth stunting. Stunting begins early in life, potentially even in utero. It is becoming increasingly clear that infant and childhood environmental enteric dysfunction plays a significant role in perpetuating the observed stunting. The repercussions of this condition include poor growth and detrimental effects on neurodevelopment, preventing affected children from reaching their full potential. The economic implications of this are substantial. The manuscript outlines the trajectory from low birth weight and suboptimal lactation to altered weaning practices and changes in the gut microbiome. It also presents current perspectives on how to mitigate these adverse effects, with a focus on early interventions in lactation and feeding during the crucial first 1000 days of life.

Enteral micronutrient supplementation and neurodevelopmental outcomes in preterm or low birth weight infants: A systematic review and meta-analysis

The association of enteral micronutrient supplementation and the neurodevelopmental outcomes of preterm or low birth weight (LBW) infants is controversial. This research was prospectively registered (CRD42023454034). We searched MEDLINE, Embase, PsycInfo, ClinicalTrials. gov, and the Cochrane Library for randomised clinical trials (RCTs) or quasi-RCTs comparing any enteral micronutrients supplementation with placebo or no supplementation in preterm or LBW infants. The primary outcome was neurodevelopmental impairment (NDI), with secondary outcomes involving various neurodevelopmental tests and disabilities. There was no evidence of an association between enteral micronutrients supplementation and the risk of NDI (RR, 1.03; 95% CI, 0.93-1.14; moderate certainty evidence). There was no evidence that the supplemented groups enhanced cognitive (MD, 0.65; 95% CI, -0.37 to 1.67; low certainty evidence), language (SMD, -0.01; 95% CI, -0.11 to 0.09; moderate certainty evidence), or motor scores (SMD, 0.04; 95% CI, -0.06 to 0.15; very low certainty evidence) or IQ (SMD, -0.20; 95% CI, -0.53 to 0.13; very low certainty evidence). Subgroup analysis showed that multiple micronutrients supplementation improved expressive language score (MD, 1.42; 95% CI, 0.39-2.45), and zinc supplementation enhanced fine motor score (SMD, 1.70; 95% CI, 0.98-2.43). The overall heterogeneity was low. This study demonstrates that enteral micronutrient supplementation is associated with little or no benefits in neurodevelopmental outcomes for preterm or LBW infants. Well-designed RCTs are needed to further ascertain these associations.

Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years

BACKGROUND

Zinc deficiency is prevalent in low- and middle-income countries, and is considered a significant risk factor for morbidity, mortality, and linear growth failure. The effectiveness of preventive zinc supplementation in reducing prevalence of zinc deficiency needs to be assessed.

OBJECTIVES

To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged 6 months to 12 years.

SEARCH METHODS

A previous version of this review was published in 2014. In this update, we searched CENTRAL, MEDLINE, Embase, five other databases, and one trials register up to February 2022, together with reference checking and contact with study authors to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of preventive zinc supplementation in children aged 6 months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalized children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions.

DATA COLLECTION AND ANALYSIS

Two review authors screened studies, extracted data, and assessed the risk of bias. We contacted study authors for missing information and used GRADE to assess the certainty of evidence. The primary outcomes of this review were all-cause mortality; and cause-specific mortality, due to all-cause diarrhea, lower respiratory tract infection (LRTI, including pneumonia), and malaria. We also collected information on a number of secondary outcomes, such as those related to diarrhea and LRTI morbidity, growth outcomes and serum levels of micronutrients, and adverse events.

MAIN RESULTS

We included 16 new studies in this review, resulting in a total of 96 RCTs with 219,584 eligible participants. The included studies were conducted in 34 countries; 87 of them in low- or middle-income countries. Most of the children included in this review were under five years of age. The intervention was delivered most commonly in the form of syrup as zinc sulfate, and the most common dose was between 10 mg and 15 mg daily. The median duration of follow-up was 26 weeks. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes was affected by risk of bias. High-certainty evidence showed little to no difference in all-cause mortality with preventive zinc supplementation compared to no zinc (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.84 to 1.03; 16 studies, 17 comparisons, 143,474 participants). Moderate-certainty evidence showed that preventive zinc supplementation compared to no zinc likely results in little to no difference in mortality due to all-cause diarrhea (RR 0.95, 95% CI 0.69 to 1.31; 4 studies, 132,321 participants); but probably reduces mortality due to LRTI (RR 0.86, 95% CI 0.64 to 1.15; 3 studies, 132,063 participants) and mortality due to malaria (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 42,818 participants); however, the confidence intervals around the summary estimates for these outcomes were wide, and we could not rule out a possibility of increased risk of mortality. Preventive zinc supplementation likely reduces the incidence of all-cause diarrhea (RR 0.91, 95% CI 0.90 to 0.93; 39 studies, 19,468 participants; moderate-certainty evidence) but results in little to no difference in morbidity due to LRTI (RR 1.01, 95% CI 0.95 to 1.08; 19 studies, 10,555 participants; high-certainty evidence) compared to no zinc. There was moderate-certainty evidence that preventive zinc supplementation likely leads to a slight increase in height (standardized mean difference (SMD) 0.12, 95% CI 0.09 to 0.14; 74 studies, 20,720 participants). Zinc supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46; 5 studies, 35,192 participants; high-certainty evidence). We report a number of other outcomes, including the effect of zinc supplementation on weight and serum markers such as zinc, hemoglobin, iron, copper, etc. We also performed a number of subgroup analyses and there was a consistent finding for a number of outcomes that co-supplementation of zinc with iron decreased the beneficial effect of zinc.

AUTHORS' CONCLUSIONS

Even though we included 16 new studies in this update, the overall conclusions of the review remain unchanged. Zinc supplementation might help prevent episodes of diarrhea and improve growth slightly, particularly in children aged 6 months to 12 years of age. The benefits of preventive zinc supplementation may outweigh the harms in regions where the risk of zinc deficiency is relatively high.

Enteral Multiple Micronutrient Supplementation in Preterm and Low Birth Weight Infants: A Systematic Review and Meta-analysis

OBJECTIVES

To assess effects of supplementation with 3 or more micronutrients (multiple micronutrients; MMN) compared to no MMN in human milk-fed preterm and low birth weight (LBW) infants.

RESULTS

Data on a subgroup of 414 preterm or LBW infants from 2 randomized controlled trials (4 reports) were included. The certainty of evidence ranged from low to very low. For growth outcomes in the MMN compared to the non-MMN group, there was a small increase in weight-for-age (2 trials, 383 participants) and height-for-age z-scores (2 trials, 372 participants); a small decrease in wasting (2 trials, 398 participants); small increases in stunting (2 trials, 399 participants); and an increase in underweight (2 trials, 396 participants). For neurodevelopment outcomes at 78 weeks, we found small increases in Bayley Scales of Infant Development, Version III (BISD-III), scores (cognition, receptive language, expressive language, fine motor, gross motor) in the MMN compared to the non-MMN group (1 trial, 27 participants). There were no studies examining dose or timing of supplementation.

CONCLUSIONS

Evidence is insufficient to determine whether enteral MMN supplementation to preterm or LBW infants who are fed mother's own milk is associated with benefit or harm. More trials are needed to generate evidence on mortality, morbidity, growth, and neurodevelopment.

Nutrition, growth, and other factors associated with early cognitive and motor development in Sub-Saharan Africa: a scoping review

BACKGROUND

Food insecurity, poverty and exposure to infectious disease are well-established drivers of malnutrition in children in Sub-Saharan Africa. Early development of cognitive and motor skills - the foundations for learning - may also be compromised by the same or additional factors that restrict physical growth. However, little is known about factors associated with early child development in this region, which limits the scope to intervene effectively. To address this knowledge gap, we compared studies that have examined factors associated with early cognitive and/or motor development within this population.

METHODS

Predetermined criteria were used to examine four publication databases (PsycInfo, Embase, Web of Science and Medline) and identify studies considering the determinants of cognitive and motor development in children aged 0-8 years in Sub-Saharan Africa.

RESULTS

In total, 51 quantitative studies met the inclusion criteria, reporting on 30% of countries across the region. Within these papers, factors associated with early child development were grouped into five themes: Nutrition, Growth and Anthropometry, Maternal Health, Malaria and HIV, and Household. Food security and dietary diversity were associated with positive developmental outcomes, whereas exposure to HIV, malaria, poor maternal mental health, poor sanitation, maternal alcohol abuse and stunting were indicators of poor cognitive and motor development.

DISCUSSION

In this synthesis of research findings obtained across Sub-Saharan Africa, factors that restrict physical growth are also shown to hinder the development of early cognitive and motor skills, although additional factors also influence early developmental outcomes. The study also reviews the methodological limitations of conducting research using Western methods in sub-Saharan Africa.

Does zinc with and without iron co-supplementation have effect on motor and mental development of children? A systematic review and meta-analysis

BACKGROUND

Effects of zinc with and without iron co-supplementation on child development are uncertain therefore the aims of this systematic review were to explore whether supplementation with zinc alone and zinc with iron in children aged 0-5 years old have beneficial or adverse effects on their mental and motor development.

METHOD

We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, Web of Science and Scopus until July 2020 and included randomized controlled trials, which assessed effects of zinc supplementation with and without iron in children less than 5 years old on mental and motor development. Data were pooled by random effects model and the Standardized Mean Differences (SMDs) with 95% confidence interval were estimated. The heterogeneity was assessed by I2.

RESULTS

Twenty-five studies with 11,559 participants were eligible to be included in this systematic review. Meta-analysis was conducted with eight articles that used Bayley Scales of Infant and Toddler Development II. We concluded that zinc alone and zinc with iron co-supplementation do not have beneficial or adverse effect on child mental and motor development at 6 and 12 months of age with low to moderate quality of the evidence. Furthermore, Zinc supplementation does not have any long term effect on child development in preschool and school age children.

CONCLUSION

Most included studies did not show the efficacy of zinc with and without iron co-supplementation on child mental and motor development up to 9 years old age. Further Randomized Controlled Trials (RCTs) need to be taken into considerations the context-based differences between countries with special focus on socio-economic differences.

Zinc supplementation for the promotion of growth and prevention of infections in infants less than six months of age

BACKGROUND

Zinc is a vital micronutrient for humans and is essential for protein synthesis, cell growth, and differentiation. Severe zinc deficiency can lead to slower physical, cognitive and sexual growth, cause skin disorders, decrease immunity, increase incidence of acute illnesses in infants and children and contribute to childhood stunting. By estimation, 17.3% of the world population is at risk of inadequate zinc intake. Such nutritional impairment increases the risk of diarrhoea and pneumonia by 20%, as well as leads to a global loss of more than 16 million disability-adjusted life years in children less than five years of age. Not only does zinc deficiency affect lives, it adds to the considerable financial burden on depleted resources in countries that are most affected. By preventing or curing this deficiency, we can improve childhood mortality, morbidity and growth.

OBJECTIVES

To assess the effectiveness of zinc supplementation for the promotion of growth, reduction in mortality, and the prevention of infections in infants less than six months of age.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2018, Issue 4), MEDLINE via PubMed (1966 to 18 May 2018), Embase (1980 to 18 May 2018), and CINAHL (1982 to 18 May 2018). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. An updated search from 1 January 2018 to 29 January 2020 was run in the following databases: CENTRAL via CRS Web, MEDLINE via Ovid, and CINAHL via EBSCOhost.

SELECTION CRITERIA

All randomised controlled (individual and cluster randomised) and quasi-randomised trials of zinc supplementation in healthy, term infants, less than six months of age comparing infant mortality, incidence of diarrhoea or respiratory illnesses, growth and/or serum zinc levels were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results (title and abstracts) and relevant full texts. Studies fulfilling prespecified inclusion criteria were included with any disagreements resolved by consensus. Extraction and analysis were then conducted. We used the GRADE approach to assess the quality of evidence as indicated by certainty in effect estimates.

MAIN RESULTS

Eight studies (with 85,629 infants) were included and five studies were meta-analysed, out of which four studies compared zinc with placebo, and one compared zinc plus riboflavin versus riboflavin. Certain growth outcomes after six months of intervention (Weight for Age Z-scores (WAZ) (standardised mean difference) (SMD) 0.16, 95% CI 0.03 to 0.29; three studies, n = 955; fixed-effect; heterogeneity Chi² P = 0.96); I² = 0%); change in WAZ (SMD 0.16, 95% CI 0.07 to 0.25; one study, n = 386; fixed-effect); (Weight-for-Length Z-score (WLZ) (SMD 0.15, 95% CI 0.02 to 0.28; three studies, n = 955; fixed-effect; heterogeneity: Chi² P = 0.81); I² = 0%); (change in WLZ (SMD 0.17, 95% CI 0.06 to 0.28; one study, n = 386; fixed-effect)) were positively affected by zinc supplementation compared to placebo. A single study reported no difference in the incidence of diarrhoea and lower respiratory tract infection with zinc supplementation. Zinc had no effect on mortality in children younger than 12 months. When zinc plus riboflavin was compared to riboflavin only, significant improvement was observed in the incidence of wasting at 24 months (risk ratio (RR) 0.59, 95% CI 0.37 to 0.96; one study, n = 296; fixed-effect), but significant worsening of incidence of stunting was present at 21 months (RR 1.53, 95% CI 1.09 to 2.16; one study, n = 298; fixed-effect).

AUTHORS' CONCLUSIONS

There was a significant positive impact of zinc supplementation on WAZ and WLZ after six months of intervention in infants compared to placebo. When a combined supplement of zinc and riboflavin was compared to riboflavin, there was a significant reduction in wasting at 24 months, but stunting at 21 months was negatively affected. Although included trials were of good-to-moderate quality, evidence that could be meta-analysed was based on a few studies which affected the overall quality of results. Regardless, there is a need for strong trials conducted in infants younger than six months before a strong recommendation can be made supporting zinc supplementation in this age group.

The role of zinc supplementation on the metallothionein system in children with autism spectrum disorder

The present research was carried out to elucidate the role of zinc (Zn) supplementation on the plasma concentration and gene expression, as well as the effects on cognitive-motor performance, in a cohort of children with autism spectrum disorder (ASD). The study was performed on a cohort of 30 pediatric subjects with ASD, encompassing an age range of 3-8 years. The impact of Zn supplementation was investigated in 3 months (or 12 weeks) on the ASD children. Each daily dosage of Zn was calculated as being equal to the body weight in kg plus 15-20 mg. The effect of Zn was also evaluated on the serum level of metallothionein 1 (MT-1A), and the severity of autism via scores on the Childhood Autism Rating Scale. The effect of Zn was investigated on the gene expression of MT1-A before and after Zn supplementation. The data of the present study showed an increase in cognitive-motor performance and an increased serum metallothionein concentration, as well as a significant lowering in the circulating serum levels of copper (Cu) following Zn supplementation. In the cohort of ASD patients, the genetic expression of MT-1 was higher after Zn therapy than before the treatment. In conclusion, Zn supplementation might be an important factor in the treatment of children with ASD.

Do effects of early life interventions on linear growth correspond to effects on neurobehavioural development? A systematic review and meta-analysis

BACKGROUND

Faltering in linear growth and neurobehavioural development during early childhood are often assumed to have common causes because of their consistent association. This notion has contributed to a global focus on the promotion of nutrition during pregnancy and childhood to improve both conditions. Our aim was to assess whether effects of interventions on linear growth are associated with effects on developmental scores and to quantify these associations.

METHODS

In this systematic review and meta-analysis, we included randomised trials done during pregnancy and in children aged 0-5 years that reported effects of any intervention on length-for-age or height-for-age Z scores (LAZ or HAZ) and on any of the following outcomes: motor, cognitive or mental, language, and social-emotional or behavioural development. We searched MEDLINE (Ovid), CINAHL (EBSCO), and PsycINFO (EBSCO) from database inception to June 25, 2019. Study-level data were extracted and, when required, authors were contacted for missing information. We calculated weighted meta-regression coefficients of the association between standardised effect sizes of interventions on LAZ or HAZ and developmental outcome scores and calculated pooled effect sizes for different types of intervention.

FINDINGS

Of the 7207 studies identified, we included 75 studies with 122 comparisons between intervention and control groups and outcomes reported for 72 275 children. Across all interventions, effect sizes on LAZ or HAZ were significantly associated with effect sizes on social-emotional scores (β 0·23, 95% CI 0·05 to 0·41; p=0·02), but not on cognitive (0·18, -0·36 to 0·72; p=0·51), language (0·12, -0·07 to 0·31; p=0·21), or motor development scores (0·23, -0·05 to 0·50; p=0·11). In studies that provided nutritional supplements, we observed positive significant pooled effect sizes on all five outcomes of LAZ or HAZ (effect size 0·05, 95% CI 0·01-0·09; p=0·01; n=50), cognitive or mental (0·06, 0·03-0·10; p<0·01; n=38), language (0·08, 0·03-0·13; p=0·01; n=21), motor (0·08, 0·04-0·12; p<0·01; n=41), and social-emotional (0·07, 0·02-0·12; p=0·01; n=20) scores. The effect sizes of nutritional supplementation on LAZ or HAZ scores were significantly associated with effect sizes on cognitive (β 0·40, 95% CI 0·04-0·77; p=0·049) and motor (0·43, 0·11-0·75; p=0·01) scores. In the 14 interventions promoting responsive care and learning opportunities, the pooled effect size on LAZ or HAZ score was not significant (-0·01, 95% CI -0·07 to 0·05; p=0·74), but pooled effect sizes on cognitive, language, and motor scores were 4 to 5 times larger (range 0·38-0·48) than the pooled effect sizes of nutritional supplementation (0·05-0·08).

INTERPRETATION

In nutritional supplementation interventions, improvements in linear growth were associated with small improvements in child development, whereas nurturing and stimulation interventions had significant effects on child development but no effects on linear growth. The determinants of linear growth and neurodevelopment are only partly shared. To nurture thriving individuals and communities, interventions should specifically target determinants of neurodevelopment and not simply linear growth.

FUNDING

University of California Davis, US Department of Agriculture National Institute of Food and Agriculture.

Nutritional, Socioeconomic, and Delivery Characteristics Are Associated with Neurodevelopment in Tanzanian Children

OBJECTIVES

To evaluate the hypothesis that various maternal, socioeconomic, delivery, and infant nutritional characteristics are associated with early childhood development in young Tanzanian children.

STUDY DESIGN

We performed a prospective cohort study among 206 HIV-exposed, uninfected and 247 HIV-unexposed Tanzanian infants who had been enrolled in 2 separate micronutrient trials (NCT00197730 and NCT00421668). Trained nurses administered culturally modified Bayley Scales of Infant and Toddler Development, 3rd edition (BSID-III), to evaluate cognitive, motor, and language development at 15 months of age. This analysis explored predictors of BSID-III z-scores using multivariable linear regression.

RESULTS

Among maternal determinants, we found that low maternal height predicted all BSID-III domains in HIV-unexposed children; low maternal education predicted lower cognitive (standardized mean difference, -0.41; 95% CI, -0.74 to -0.08) and lower gross motor scores (standardized mean difference, -0.32; 95% CI, -0.61 to -0.04) in HIV-exposed children. Among delivery characteristics, facility delivery predicted higher cognitive scores (standardized mean difference, 1.36; 95% CI, 0.26-2.46); and oxytocin administration predicted lower fine motor scores (standardized mean difference, -0.48; 95% CI, -0.87 to -0.09) in HIV-exposed children. Higher length-for-age z-scores at 6 weeks of age predicted better cognitive (standardized mean difference, 0.15; 95% CI, 0.01-0.29) and expressive language scores (standardized mean difference, 0.16; 95% CI, 0.02-0.29) at 15 months in HIV-exposed infants.

CONCLUSIONS

This hypothesis-generating study found significant associations between nutritional status and health of the mother and child, and maternal educational attainment, with direct measures of early childhood development at 15 months of age. In addition, several aspects of delivery (facility birth and oxytocin administration) were associated with early childhood development. Future intervention trials should focus on modifiable maternal, infant, and obstetric factors to strengthen the evidence base concerning early childhood development.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00197730 and NCT00421668.

Does early vitamin B12 supplementation improve neurodevelopment and cognitive function in childhood and into school age: a study protocol for extended follow-ups from randomised controlled trials in India and Tanzania

INTRODUCTION

As many as 250 million children under the age of 5 may not be reaching their full developmental potential partly due to poor nutrition during pregnancy and the first 2 years of life. Micronutrients, including vitamin B₁₂, are important for the development of brain structure and function; however, the timing, duration and severity of deficiencies may alter the impact on functional development outcomes. Consequently, to fully explore the effect of vitamin B₁₂ on cognitive function, it is crucial to measure neurodevelopment at different ages, in different populations and with vitamin B₁₂ supplementation at different times during the critical periods of neurodevelopment.

METHODS AND ANALYSIS

In this project, we follow up children from four recently completed randomised placebo-controlled trials of oral vitamin B₁₂ supplementation, two in India and two in Tanzania, to explore the long-term effects on neurodevelopmental outcomes and growth. All the included trials provided at least two recommended dietary allowances of oral vitamin B₁₂ daily for at least 6 months. Vitamin B₁₂ was supplemented either during pregnancy, early infancy or early childhood. Primary outcomes are neurodevelopmental status, cognitive function and growth later in childhood. We apply validated and culturally appropriate instruments to identify relevant developmental outcomes. All statistical analyses will be done according to intention-to-treat principles. The project provides an excellent opportunity to examine the effect of vitamin B₁₂ supplementation in different periods during early life and measure the outcomes later in childhood.

ETHICS AND DISSEMINATION

The study has received ethical approvals from all relevant authorities in Norway, USA, Tanzania and India and complies fully with ethical principles for medical research. Results will be presented at national and international research and policy meetings and published in peer-reviewed scientific journals, preferably open access.

TRIAL REGISTRATION NUMBER

NCT00641862 (Bangalore); NCT00717730, updated CTRI/2016/11/007494 (Delhi); NCT00197548 and NCT00421668 (Dar es Salaam).

The role of nutrition in integrated early child development in the 21st century: contribution from the Maternal and Child Nutrition journal

Even though it is widely recognized that early childhood development (ECD) is one of the most important predictors of future social capital and national productivity, the recently published ECD Lancet Series reports that about 250 million children under 5 years are at risk of not reaching their developmental potential, mainly as a result of poverty and social injustice. So why is this and what will it take to reverse this situation? The purpose of this special issue is to highlight important contributions from previously published articles in Maternal & Child Nutrition to the field of nutrition and ECD. The collection of papers presented in this special issue collectively indicates that although nutrition-specific interventions are essential for child development, they are not sufficient by themselves for children to reach their full developmental potential. This is because ECD is influenced by many other factors besides nutrition, including hand washing/sanitation, parenting skills, psychosocial stimulation, and social protection. Future research should focus on mixed-methods implementation science seeking to understand how best to translate evidence-based integrated ECD packages into effective intersectoral policies and programs on a large scale. In addition to health and nutrition, these programs need to consider and include responsive parenting (including responsive feeding), learning stimulation, education, and social protection. Future studies should also address if and how childhood obesity affects human physical, socioemotional, and cognitive development.

The effect of daily zinc and/or multivitamin supplements on early childhood development in Tanzania: results from a randomized controlled trial

Impaired childhood development has lifelong consequences for educational attainment and wage-earning potential. Micronutrient supplements have the potential to improve development. The objective of this study was to determine the effect of daily zinc and/or multivitamin (vitamins C, E and B-complex) supplements on development among Tanzanian infants. In this randomized, 2 × 2 factorial, double-blind trial, 2400 infants were randomized to zinc (Zn), multivitamins (MV), zinc and multivitamins (Zn + MV) or placebo at 6 weeks of age. At approximately 15 months, a sub-sample of 247 children underwent developmental assessment using the cognitive, language (receptive and expressive) and motor (fine and gross) scales of the Bayley Scales of Infant and Toddler Development Third Edition (BSID-III). Mean BSID-III scores were compared using univariate and multivariate linear regression models adjusted for child's sex, post-conceptual age and test administrator. Logistic regressions were used to assess odds of low developmental scores. We did not detect a significant difference in mean BSID-III scores in any of the five domains in univariate or multivariate models comparing each of the four treatment groups. We also did not detect a significant difference in mean BSID-III scores when comparing children who received zinc supplements versus those who did not, or in comparisons of children who received multivitamin supplements versus those who did not. There was no significant difference in odds of a low BSID-III score in any of the five domains in treatment arms either. Because neither daily zinc nor multivitamin (vitamins B-complex, C and E) supplementation led to improvements in any of the developmental domains assessed using the BSID-III, we recommend pursuing alternative interventions to promote early childhood development in vulnerable populations. © 2016 John Wiley & Sons Ltd.