Childhood stunting is the best overall indicator of children's well‐being and an accurate reflection of social inequalities. Stunting is the most prevalent form of child malnutrition with an estimated 161 million children worldwide in 2013 falling below −2 SD from the length‐for‐age/height‐for‐age World Health Organization Child Growth Standards median. Many more millions suffer from some degree of growth faltering as the entire length‐for‐age/height‐for‐age z‐score distribution is shifted to the left indicating that all children, and not only those falling below a specific cutoff, are affected. Despite global consensus on how to define and measure it, stunting often goes unrecognized in communities where short stature is the norm as linear growth is not routinely assessed in primary health care settings and it is difficult to visually recognize it. Growth faltering often begins in utero and continues for at least the first 2 years of post‐natal life. Linear growth failure serves as a marker of multiple pathological disorders associated with increased morbidity and mortality, loss of physical growth potential, reduced neurodevelopmental and cognitive function and an elevated risk of chronic disease in adulthood. The severe irreversible physical and neurocognitive damage that accompanies stunted growth poses a major threat to human development. Increased awareness of stunting's magnitude and devastating consequences has resulted in its being identified as a major global health priority and the focus of international attention at the highest levels with global targets set for 2025 and beyond. The challenge is to prevent linear growth failure while keeping child overweight and obesity at bay.
This review summarizes the impact of stunting, highlights recent research findings, discusses policy and programme implications and identifies research priorities. There is growing evidence of the connections between slow growth in height early in life and impaired health and educational and economic performance later in life. Recent research findings, including follow‐up of an intervention trial in Guatemala, indicate that stunting can have long‐term effects on cognitive development, school achievement, economic productivity in adulthood and maternal reproductive outcomes. This evidence has contributed to the growing scientific consensus that tackling childhood stunting is a high priority for reducing the global burden of disease and for fostering economic development. Follow‐up of randomized intervention trials is needed in other regions to add to the findings of the Guatemala trial. Further research is also needed to: understand the pathways by which prevention of stunting can have long‐term effects; identify the pathways through which the non‐genetic transmission of nutritional effects is mediated in future generations; and determine the impact of interventions focused on linear growth in early life on chronic disease risk in adulthood.
The International Lipid‐Based Nutrient Supplements (iLiNS) Project began in 2009 with the goal of contributing to the evidence base regarding the potential of lipid‐based nutrient supplements (LNS) to prevent undernutrition in vulnerable populations. The first project objective was the development of acceptable LNS products for infants 6–24 months and for pregnant and lactating women, for use in studies in three countries (Burkina Faso, Ghana and Malawi). This paper shares the rationale for a series of decisions in supplement formulation and design, including those related to ration size, ingredients, nutrient content, safety and quality, and packaging. Most iLiNS supplements have a daily ration size of 20 g and are intended for home fortification of local diets. For infants, this ration size is designed to avoid displacement of breast milk and to allow for dietary diversity including any locally available and accessible nutrient‐dense foods. Selection of ingredients depends on acceptability of flavour, micronutrient, anti‐nutrient and essential fatty acid contents. The nutrient content of LNS designed to prevent undernutrition reflects the likelihood that in many resource‐poor settings, diets of the most nutritionally vulnerable individuals (infants, young children, and pregnant and lactating women) are likely to be deficient in multiple micronutrients and, possibly, in essential fatty acids. During ingredient procurement and LNS production, safety and quality control procedures are required to prevent contamination with toxins or pathogens and to ensure that the product remains stable and palatable over time. Packaging design decisions must include consideration of product protection, stability, convenience and portion control.
The aim of this study was to quantify the excess cases of pediatric and maternal disease, death, and costs attributable to suboptimal breastfeeding rates in the United States. Using the current literature on the associations between breastfeeding and health outcomes for nine pediatric and five maternal diseases, we created Monte Carlo simulations modeling a hypothetical cohort of U.S. women followed from age 15 to age 70 years and their children from birth to age 20 years. We examined disease outcomes using (a) 2012 breastfeeding rates and (b) assuming that 90% of infants were breastfed according to medical recommendations. We measured annual excess cases, deaths, and associated costs, in 2014 dollars, using a 2% discount rate. Annual excess deaths attributable to suboptimal breastfeeding total 3,340 (95% confidence interval [1,886 to 4,785]), 78% of which are maternal due to myocardial infarction (n = 986), breast cancer (n = 838), and diabetes (n = 473). Excess pediatric deaths total 721, mostly due to Sudden Infant Death Syndrome (n = 492) and necrotizing enterocolitis (n = 190). Medical costs total $3.0 billion, 79% of which are maternal. Costs of premature death total $14.2 billion. The number of women needed to breastfeed as medically recommended to prevent an infant gastrointestinal infection is 0.8; acute otitis media, 3; hospitalization for lower respiratory tract infection, 95; maternal hypertension, 55; diabetes, 162; and myocardial infarction, 235. For every 597 women who optimally breastfeed, one maternal or child death is prevented. Policies to increase optimal breastfeeding could result in substantial public health gains. Breastfeeding has a larger impact on women's health than previously appreciated.
The Baby‐friendly Hospital Initiative (BFHI) is a key component of the World Health Organization/United Nations Children's Fund Global Strategy for Infant and Young Child Feeding. The primary aim of this narrative systematic review was to examine the impact of BFHI implementation on breastfeeding and child health outcomes worldwide and in the United States. Experimental, quasi‐experimental and observational studies were considered eligible for this review if they assessed breastfeeding outcomes and/or infant health outcomes for healthy, term infants born in a hospital or birthing center with full or partial implementation of BFHI steps. Of the 58 reports included in the systematic review, nine of them were published based on three randomized controlled trials, 19 followed quasi‐experimental designs, 11 were prospective and 19 were cross‐sectional or retrospective. Studies were conducted in 19 different countries located in South America, North America, Western Europe, Eastern Europe, South Asia, Eurasia and Sub‐Saharan Africa. Adherence to the BFHI Ten Steps has a positive impact on short‐term, medium‐term and long‐term breastfeeding (BF) outcomes. There is a dose–response relationship between the number of BFHI steps women are exposed to and the likelihood of improved BF outcomes (early BF initiation, exclusive breastfeeding (EBF) at hospital discharge, any BF and EBF duration). Community support (step 10) appears to be essential for sustaining breastfeeding impacts of BFHI in the longer term.
An estimated 165 million children are stunted due to the combined effects of poor nutrition, repeated infection and inadequate psychosocial stimulation. The complementary feeding period, generally corresponding to age 6–24 months, represents an important period of sensitivity to stunting with lifelong, possibly irrevocable consequences. Interventions to improve complementary feeding practices or the nutritional quality of complementary foods must take into consideration the contextual as well as proximal determinants of stunting. This review presents a conceptual framework that highlights the role of complementary feeding within the layers of contextual and causal factors that lead to stunted growth and development and the resulting short‐ and long‐term consequences. Contextual factors are organized into the following groups: political economy; health and health care systems; education; society and culture; agriculture and food systems; and water, sanitation and environment. We argue that these community and societal conditions underlie infant and young child feeding practices, which are a central pillar to healthy growth and development, and can serve to either impede or enable progress. Effectiveness studies with a strong process evaluation component are needed to identify transdisciplinary solutions. Programme and policy interventions aimed at preventing stunting should be informed by careful assessment of these factors at all levels.
Pregnant women and newborns are at increased risk of vitamin D deficiency. Our objective was to create a global summary of maternal and newborn vitamin D status. We completed a systematic review (1959–2014) and meta‐analysis of studies reporting serum 25‐hydroxyvitamin D [25(OH)D] concentration in maternal and newborn populations. The 95 identified studies were unevenly distributed by World Health Organization (WHO) region: Americas (24), European (33), Eastern Mediterranean (13), South‐East Asian (7), Western Pacific (16) and African (2). Average maternal 25(OH)D concentrations (nmol L−1) by region were 47–65 (Americas), 15–72 (European), 13–60 (Eastern Mediterranean), 20–52 (South‐East Asian), 42–72 (Western Pacific) and 92 (African). Average newborn 25(OH)D concentrations (nmol L−1) were 35–77 (Americas), 20–50 (European), 5–50 (Eastern Mediterranean), 20–22 (South‐East Asian), 32–67 (Western Pacific) and 27–35 (African). The prevalences of 25(OH)D <50 and <25 nmol L−1 by WHO region in pregnant women were: Americas (64%, 9%), European (57%, 23%), Eastern Mediterranean (46%, 79%), South‐East Asian (87%, not available) and Western Pacific (83%, 13%). Among newborns these values were: Americas (30%, 14%), European (73%, 39%), Eastern Mediterranean (60%, not available), South‐East Asian (96%, 45%) and Western Pacific (54%, 14%). By global region, average 25(OH)D concentration varies threefold in pregnant women and newborns, and prevalence of 25(OH)D <25 nmol L−1 varies eightfold in pregnant women and threefold in newborns. Maternal and newborn 25(OH)D concentrations are highly correlated. Addressing vitamin D deficiency in pregnant women and newborns should be a global priority. To protect children from the adverse effects of vitamin D deficiency requires appropriate interventions during both pregnancy and childhood.
This paper outlines the economic rationale for investments that reduce stunting. We present a framework that illustrates the functional consequences of stunting in the 1000 days after conception throughout the life cycle: from childhood through to old age. We summarize the key empirical literature around each of the links in the life cycle, highlighting gaps in knowledge where they exist. We construct credible estimates of benefit–cost ratios for a plausible set of nutritional interventions to reduce stunting. There are considerable challenges in doing so that we document. We assume an uplift in income of 11% due to the prevention of one fifth of stunting and a 5% discount rate of future benefit streams. Our estimates of the country‐specific benefit‐cost ratios for investments that reduce stunting in 17 high‐burden countries range from 3.6 (DRC) to 48 (Indonesia) with a median value of 18 (Bangladesh). Mindful that these results hinge on a number of assumptions, they compare favourably with other investments for which public funds compete.
In 2012, the World Health Organization adopted a resolution on maternal, infant and young child nutrition that included a global target to reduce by 40% the number of stunted under‐five children by 2025. The target was based on analyses of time series data from 148 countries and national success stories in tackling undernutrition. The global target translates to a 3.9% reduction per year and implies decreasing the number of stunted children from 171 million in 2010 to about 100 million in 2025. However, at current rates of progress, there will be 127 million stunted children by 2025, that is, 27 million more than the target or a reduction of only 26%. The translation of the global target into national targets needs to consider nutrition profiles, risk factor trends, demographic changes, experience with developing and implementing nutrition policies, and health system development. This paper presents a methodology to set individual country targets, without precluding the use of others. Any method applied will be influenced by country‐specific population growth rates. A key question is what countries should do to meet the target. Nutrition interventions alone are almost certainly insufficient, hence the importance of ongoing efforts to foster nutrition‐sensitive development and encourage development of evidence‐based, multisectoral plans to address stunting at national scale, combining direct nutrition interventions with strategies concerning health, family planning, water and sanitation, and other factors that affect the risk of stunting. In addition, an accountability framework needs to be developed and surveillance systems strengthened to monitor the achievement of commitments and targets.
Table of Contents Summary 25 1. Introduction 33 1.1 Importance of complementary feeding for child health 33 1.2 Guiding principles for complementary feeding 34 1.3 Scope and organization of this report 34 2. Energy and nutrients needed from complementary foods 35 2.1 Energy, protein and lipids 35 2.2 Micronutrients 35 3. Methods 36 3.1 Sources searched and search strategy 36 3.2 Measurement of the treatment effect of interventions 36 3.3 Evaluation of methodological quality and level of evidence 37 3.4 Number of relevant studies identified 38 4. Findings of the systematic review 38 4.1 Types of intervention strategies 38 4.1.1 Educational interventions 38 4.1.2 Provision of food offering extra energy (with or without micronutrient fortification) 43 4.1.3 Micronutrient fortification of complementary foods 43 4.1.4 Increasing energy density of complementary foods through simple technology 46 4.1.5 Categorization of results by intervention strategy 46 4.2 Growth outcomes 46 4.2.1 Interventions using educational approaches 46 4.2.2 Interventions in which provision of complementary food was the only treatment 49 4.2.3 Interventions in which provision of complementary food was combined with another strategy, usually education for mothers 51 4.2.4 Interventions in which complementary foods were fortified with additional micronutrients 53 4.2.5 Interventions to increase energy density of complementary foods 55 4.3 Morbidity outcomes 55 4.3.1 Interventions using educational approaches 55 4.3.2 Interventions in which provision of complementary food was the only treatment 57 4.3.3 Interventions in which provision of complementary food was combined with another strategy, usually education for mothers 57 4.3.4 Interventions in which complementary foods were fortified with additional micronutrients 58 4.3.5 Interventions to increase energy density of complementary foods 59 4.4 Child development 61 4.4.1 Interventions in which provision of complementary food was the only treatment 61 4.4.2 Interventions in which complementary foods were fortified with additional micronutrients 62 4.5 Micronutrient intake 63 4.5.1 Intervention studies using educational approaches 63 4.5.2 Interventions in which provision of complementary food was the only treatment 64 4.5.3 Interventions in which provision of complementary food was combined with another strategy, usually education for mothers 64 4.5.4 Interventions in which complementary foods were fortified with additional micronutrients 65 4.5.5 Interventions to increase energy density of complementary foods 66 4.6 Iron status 66 4.6.1 Intervention studies using educational approaches 66 4.6.2 Interventions in which complementary food was provided, with or without another strategy such as education for mothers 68 4.6.3 Interventions in which commercially processed complementary foods were fortified with iron or multiple micronutrients 68 4.6.4 Interventions in which home fortification of complementary foods was the primary intervention 68 4.7 Zinc status 72 4.7.1 Interventions in which complementary foods were fortified with additional micronutrients, either commercially or with home fortification 72 4.8 Vitamin A status 72 4.8.1 Interventions in which complementary foods were fortified with additional micronutrients, either commercially or with home fortification 72 5. Discussion 75 5.1 Impact of complementary feeding interventions on growth 75 5.2 Impact of complementary feeding interventions on morbidity 77 5.3 Impact of complementary feeding interventions on child development 78 5.4 Impact of complementary feeding interventions on micronutrient intake 78 5.5 Impact of complementary feeding interventions on micronutrient status 78 5.6 Conclusions 79 Acknowledgments 82 References 82 Summary Introduction Complementary feeding interventions are usually targeted at the age range of 6–24 months, which is the time of peak incidence of growth faltering, micronutrient deficiencies and infectious illnesses in developing countries. After 2 years of age, it is much more difficult to reverse the effects of malnutrition on stunting, and some of the functional deficits may be permanent. Therefore, interventions that are effective at reducing malnutrition during this vulnerable period should be a high priority. Although several types of interventions can be targeted to this age range (e.g. micronutrient supplementation), a food‐based, comprehensive approach may be more effective and sustainable than programmes targeting individual nutrient deficiencies. For this review, a broad definition of ‘complementary feeding interventions’ is used so as to capture the full range of strategies that can be used. Scope and methods of the review The interventions described in this review generally include one or more components related to the Guiding Principles for Complementary Feeding of the Breastfed Child (PAHO/WHO 2003). The 10 guiding principles cover: (1) duration of exclusive breastfeeding and age of introduction of complementary foods; (2) maintenance of breastfeeding; (3) responsive feeding; (4) safe preparation and storage of complementary foods; (5) amount of complementary food needed; (6) food consistency; (7) meal frequency and energy density; (8) nutrient content of complementary foods; (9) use of vitamin‐mineral supplements or fortified products for infant and mother; and (10) feeding during and after illness. This review includes any relevant intervention that targeted children within the age range of 6–24 months. In some cases, the intervention may have included children older than 24 months, but in all studies at least some of the children were between 6 and 24 months. The assumption is that many of the children in these studies were breastfed, although a certain proportion will have terminated breastfeeding before 24 months. Although strategies for optimizing the duration of exclusive breastfeeding or increasing the total duration of breastfeeding may have a direct influence on several of the outcomes of interest, this review will not cover those strategies because another report will review those results. The primary outcomes of interest for this review include growth, morbidity and child development. Micronutrient intake and micronutrient status were also included as outcomes because of their link to these key functional outcomes. Studies that assessed the impact of complementary feeding interventions on feeding practices only were not included because of time constraints and because it has been demonstrated previously that appropriately designed interventions can have a positive impact on feeding practices (Caulfield et al. 1999). For most intervention strategies and outcomes, the literature search was focused on the period from 1996 to 2006, as the previous review by Caulfield et al. (1999) covered the period from 1970 to 1997. For certain interventions not covered in the previous review (i.e. using amylase to increase energy density and interventions focused on iron status outcomes), studies dating back to 1990 were included. Only studies conducted in developing countries were included. The search was conducted using electronic methods, inspection of websites of key private voluntary organizations and the bibliographies of published papers, and personal contacts. The two authors of this review independently assessed the quality of each of the reviewed studies, and those scored as 2– (non‐randomized studies with a high risk of bias) were not included in the tabulation of results. In total, 42 papers were included in the review. These papers report results from 29 efficacy trials and 13 effectiveness studies or programme reports from 25 developing countries. Interventions were considered efficacy trials if there was a high degree of assurance of delivery of the ‘treatment’, generally under carefully controlled research conditions (e.g. provision of a fortified complementary food with frequent follow‐up to assess adherence). Evaluations of interventions carried out in a programme setting, generally with less ability to control delivery of and adherence to ‘treatment’, were considered effectiveness studies. To compare growth (weight and length) results across studies (when these results were reported as means ± SD), we calculated the treatment effect size for each outcome of interest using the formula: When possible, the effect sizes for each outcome were averaged across interventions to obtain a rough estimate of overall impact. Effect size can be categorized as small (∼0.2), medium (∼0.5) or large (∼0.8). Interventions were grouped into five categories depending on the main strategy used: 1 education about complementary feeding as the main treatment, 2 complementary food or a food product offering extra energy (with or without added micronutrients) provided as the only treatment, 3 provision of food combined with some other strategy, usually education for mothers, 4 fortification of complementary foods (centrally processed fortified foods or home‐fortification products) with micronutrients (with no difference in energy provided to intervention vs. control groups), and 5 increased energy density and/or nutrient bioavailability of complementary foods through the use of simple technologies. Some studies had more than one intervention group and may thus be included in more than one of the categories. In these situations, only the results for the intervention groups that are relevant to the comparison in question are included in that section. Some of the interventions targeted only malnourished children, but most were aimed at all children in the target age range. Results Growth Nearly all of the studies assessed growth as an outcome. There were six efficacy trials and five effectiveness studies in which the main intervention strategy was education about complementary feeding. Taking these 11 studies together, educational interventions had a modest effect on weight (mean effect size = 0.28; range −0.06, 0.96) and linear growth (mean effect size 0.20, range 0.04, 0.64). The two educational interventions with the greatest impact on both weight and length gain (effect sizes of 0.34–0.96) were the projects in Peru (Penny et al. 2005) and China (Guldan et al. 2000). In both of these, a key message was to regularly provide an animal‐source food to the infant (chicken liver, egg or fish in Peru; egg in China). The other educational intervention with a relatively large impact on weight (though not on length) was a study in Bangladesh that targeted children with low weight‐for‐age at baseline (Roy et al. 2005). That intervention also promoted the home preparation of a complementary food mixture that included egg, meat or fish. There were seven efficacy trials and one effectiveness study in which the only intervention strategy was provision of complementary food (often fortified). The results were somewhat inconsistent: there was a positive impact in Ghana and Malawi but no impact in South Africa, Indonesia or Brazil. The overall mean effect size was 0.60 (range −0.02, 2.99) for weight and 0.47 (range −0.04, 1.81) for linear growth, but these effects are inflated by the results from Nigeria (Obatolu 2003) (effect sizes: weight = 2.99, length = 1.81). Excluding that study, the mean effect size was 0.26 (range −0.02, 0.57) for weight and 0.28 (range −0.04, 0.69) for length. For the combination of provision of complementary food with some other strategy (usually education), there were two efficacy trials and six effectiveness studies. With these eight studies combined, the average effect size for weight was 0.35 (range 0.18, 0.66) and that for linear growth was 0.17 (range 0, 0.32). Two studies specifically evaluated whether provision of food plus education was more effective than education alone (Bhandari et al. 2001; Roy et al. 2005). In India (Bhandari et al. 2001), the food plus education group gained 250 g more weight and 0.4 cm more than the control group during the 8‐month intervention, whereas the education‐only group gained only 90 g more than the control group and did not have any advantage in length gain. In Bangladesh (Roy et al. 2005), results for the education‐only group were intermediate between those of the food plus education and control groups. Thus, in these two settings the inclusion of a food supplement was more effective than education alone. The effect of fortification of complementary foods (with no difference in the amount of energy provided to intervention and control groups) on growth was evaluated in six efficacy trials, three of which involved home fortification using micronutrient supplements (powders or crushable tablets). The other three studies used cereal/legumes mixes or a milk formulation to which the micronutrients were added during processing. Only in the fortified‐milk study (conducted in India) was there a significant impact on growth. The average effect size for all six studies was 0.11 (range −0.22, 0.37) for weight and 0.12 (range −0.02, 0.45) for length. There were no effectiveness studies identified within this category. There were five efficacy trials in which the main strategy was aimed at increasing the energy density of the usual complementary food. Only two of these trials had a significant impact on growth (John & Gopaldas 1993; Moursi et al. 2003). In the other three (Mamiro et al. 2004; Hossain et al. 2005a; Owino et al. 2007), there was no increase in energy intake, so the lack of impact on growth is not surprising. The average effect size across all trials was 0.35 (range −0.13, 1.37) for weight and 0.23 (range −0.25, 0.71) for linear growth. Figures 1 and 2 compare the effect sizes for growth across each category of intervention. The average effect sizes are in the small to medium range, which is in agreement with estimates from the previous review of interventions completed between 1970 and 1997 [effect size generally 0.10–0.50 (Caulfield et al. 1999)]. 1 Effect sizes of different intervention strategies for growth in weight. ED = education about child feeding alone; FD = provision of complementary food alone; FD+ED = provision of complementary food plus some other strategy, usually education; FT = Fortification of complementary foods; EN = increased energy density. Each curve shows the mean effect size and range (minimum and maximum). The study by Obatolu (2003) was an outlier (effect size for weight at 18 months = 2.99) and was thus excluded. 2 Effect sizes of different intervention strategies for linear growth. ED = education about child feeding alone; FD = provision of complementary food alone; FD+ED = provision of complementary food plus some other strategy, usually education; FT = fortification of complementary foods; EN = increased energy density. Each curve shows the mean effect size and range (minimum and maximum). The study by Obatolu (2003) was an outlier (effect size for length at 18 months = 1.81) and was thus excluded. Morbidity Only 10 of the intervention studies included data on morbidity outcomes. In most of these, there were no significant effects on morbidity. Most studies included morbidity as a secondary outcome and were not designed or powered to detect differences in morbidity. Two of the educational interventions showed a beneficial effect: a reduction in diarrhoea in Brazil (Vitolo et al. 2005) and a reduction in upper respiratory infection in Vietnam (Schroeder et al. 2002). The fortified‐milk study in India demonstrated a significant reduction in both diarrhoea and acute lower respiratory illness (Sazawal et al. 2007), and a study evaluating home fortification with a micronutrient powder (‘Sprinkles™’) in Pakistan showed beneficial effects on diarrhoea and fever (Sharieff et al. 2006). However, in three studies the interventions were associated with increased symptoms of morbidity. This was evident in food supplementation interventions in Bangladesh [during the first 2 months of the intervention (Roy et al. 2005)] and in India (Bhandari et al. 2001) and in an energy‐density intervention in Congo (Moursi et al. 2003). In India, the adverse effects on fever and dysentery could have been due to the reduction in breastfeeding that occurred in the intervention group. Unhygienic preparation and storage of complementary foods is another possible explanation for adverse effects of these interventions on morbidity. Behavioural development Only four studies, all efficacy trials, included data on behavioural development. The provision of a fat‐based fortified food product or micronutrients alone improved gross motor development in Ghana (Adu‐Afarwuah et al. 2007) but these types of interventions did not have any significant effect on developmental outcomes in South Africa (Oelofse et al. 2003) or India (Dhingra et al. 2004). Positive results of supplementation with extra energy in Indonesia were seen only in a subgroup (Pollitt et al. 2002). Micronutrient intake Only a few studies reported data on iron, zinc and vitamin A intakes. Education for mothers significantly increased child iron intake in Malawi, India and Peru, but did not have any significant effect on intakes in Brazil. Taking those four studies together, the intervention increased iron intake from complementary foods by 24% (range −7%, 60%) and zinc intake by 26% (range 9%, 53%). Despite those increases, mean iron and zinc intake from complementary foods was still well below recommended intakes in some sites. In Brazil (Santos et al. 2005) a large‐scale food supplementation programme failed to have an impact on intakes of these three micronutrients. There was also no impact of traditional processing of complementary foods in Tanzania (Mamiro et al. 2004). The largest impact on micronutrient intakes resulted from fortification strategies, which increased iron intake by 145–207% in Mexico and Ghana, zinc intake by 201–271% in Ecuador and Ghana, and vitamin A intake by 107% to more than 2300% in Ecuador and Ghana. Anaemia and iron status Four studies of educational interventions included data on anaemia and/or iron status. In India and China there was an increase in mean haemoglobin but in Nicaragua and Brazil there was no significant effect. The difference in impact across studies could be due to the specificity of the messages regarding enhancement of iron intake in the two former studies, compared with the latter two projects. Overall, for these four studies the average impact was an increase of 4 g L−1 in mean haemoglobin and a reduction in the prevalence of anaemia of 5 percentage points. In 12 studies, the target group was provided with a complementary food that was fortified with iron (and sometimes other micronutrients as well). The comparison group received either no additional food (five studies: two efficacy trials and three programme evaluations), or an unfortified complementary food (seven efficacy trials). For the former group of five studies, the average impact was an increase of 4 g L−1 in mean haemoglobin and a reduction in the prevalence of anaemia of 13 percentage points. For the latter group of seven studies, the average effect was an increase of 6 g L−1 in mean haemoglobin and a reduction in the prevalence of anaemia of 17 percentage points. Another seven studies (five efficacy trials, two programme evaluations) evaluated the effect of home fortification of complementary foods using powders, crushable tablets or fat‐based products. Taking these seven studies together, the average impact was an increase of 8 g L−1 in mean haemoglobin and a reduction in the prevalence of anaemia of 21 percentage points. Some of the above studies included direct assessments of iron status, such as ferritin values. In most cases, the impact on the prevalence of iron deficiency was greater than the impact on anaemia, indicating that other factors such as malaria contribute to the persistently high rates of anaemia in certain populations. Zinc status Only five studies reported plasma zinc concentrations, all of which involved evaluation of a fortified complementary food (three efficacy trials, one programme evaluation), or a home‐fortification product (efficacy trial). The fortified foods provided 3–6.5 mg day−1 zinc, and the daily home‐fortification ‘foodlet’ (crushable tablet) provided 10 mg day−1. In the four studies using fortified foods, none demonstrated a significant difference between intervention and control groups in mean plasma zinc concentration or the percentage of children with low plasma Zn. In the foodlet intervention trial in South Africa, the group receiving daily micronutrients had significantly higher plasma zinc than the placebo group (Smuts et al. 2005). Overall, these results indicate that complementary foods fortified with multiple micronutrients, including zinc, have little impact on plasma zinc concentration, perhaps because of the relatively low bioavailability of zinc when consumed with cereal‐based or cereal/legume blend foods. Vitamin A status Seven intervention studies to evaluate the impact of a fortified complementary food (three efficacy trials, two programme evaluations) or home‐fortification products (two efficacy trials) included data on vitamin A status. There was a significant impact on mean serum vitamin A concentration in four of the five interventions using fortified complementary foods, and a reduction in the incidence of vitamin A deficiency in the two studies (of these five) that evaluated this outcome. There was no significant impact on serum vitamin A concentration in the two studies using home‐fortification products, which the investigators attributed to widespread participation in vitamin A supplementation programmes that occurred during the study time period. Taken together, these seven studies indicate that complementary foods fortified with vitamin A can reduce the incidence of vitamin A deficiency (by an average of ∼−13 percentage points in the two studies that reported this), although this impact may be obscured by concurrent vitamin A supplementation programmes. Conclusions The results of this review indicate that there is no single universal ‘best’ package of components in complementary feeding interventions because the needs of the target population vary greatly. The impact of such interventions is thus context specific, and depends on factors such as the initial prevalence of malnutrition, the degree of household food insecurity, the energy density of traditional complementary foods and the availability of micronutrient‐rich local foods. Child growth was the most common outcome measured, but it may not be the most sensitive indicator of benefit because of other constraints that limit the extent to which a child's growth (particularly height) can respond to post‐natal interventions. The impact of these interventions on child growth was mixed. When the primary approach was education about child feeding, interventions that included a strong emphasis on feeding nutrient‐rich animal‐source foods were more likely to show an effect. When a complementary food was provided, with or without concurrent strategies such as nutrition education, the studies in Africa and South Asia generally showed positive effects, while those in other regions were more variable. This may be related to the relatively high prevalence of food insecurity in Africa and South Asia. In such contexts, providing additional food – not just education – may facilitate the ability of families to follow complementary feeding guidelines. In several studies, the impact of providing a complementary food, in combination with nutrition education, was evident only in the younger children. This underscores the importance of beginning complementary feeding programmes during infancy, when nutrient needs relative to energy intake are the highest and the ability of the child to respond to a nutritional intervention is the greatest. Because most interventions in which a complementary food was provided used fortified foods, it is not possible to determine whether the positive effects on growth are due to greater energy/protein/fat intake, greater micronutrient intake, or the combination. It is noteworthy that the interventions in which micronutrient fortification was the sole component (i.e. comparisons of fortified vs. unfortified complementary foods, or evaluations of home fortification) generally had little or no effect on growth. Further research on the biological mechanisms underlying growth effects, including the potential roles of milk protein and essential fatty acids, is needed. Increasing the energy density of complementary foods may have a positive effect on growth when the traditional complementary food has a low energy density and infants are unable to adequately compensate by consuming a higher volume or being fed more frequently. However, before including this strategy in a complementary feeding programme, it is advisable to first demonstrate that increasing energy density of the traditional food will actually result in increased total daily energy intake (including energy intake from breastmilk). It should be noted that increasing energy density will not necessarily result in adequate micronutrient intake, so this strategy should be accompanied by other efforts to improve dietary adequacy. The potential for an impact on growth appears to be greater with interventions using key educational messages, provision of complementary food with or without fortification, or increased energy density of complementary foods than with interventions based on fortification alone. Although the effect sizes for growth were generally modest (0.1–0.5), the potential impact is larger (0.5–0.6) if programmes are optimally designed and implemented. Furthermore, the impact on the lower tail of the distribution – that is, on stunting rates – could be considerably larger than the effect on the mean height z‐score. In general, effect sizes for growth of interventions providing complementary foods were greater for efficacy trials than for programmes. This is not surprising, given the logistical challenges of ensuring consistent delivery of food (and education) in large‐scale programmes. Some of the complementary feeding interventions reviewed had a beneficial impact on morbidity rates, but there is the potential for adverse effects of strategies such as food supplementation and increased energy density. This may be due to excessive displacement of breastmilk and/or unhygienic preparation and storage of complementary foods. This highlights the need to couple complementary feeding interventions with counselling regarding continued breastfeeding, responsive feeding and hygienic practices. There is very little information on the impact of complementary feeding interventions on behavioural development, but recent studies in infants have yielded promising results. It is important to include assessments of behavioural development in such evaluations, as these outcomes may be more sensitive to improvements in child nutrition than outcomes such as growth and morbidity. With regard to micronutrient intake, the results of educational interventions indicate that it is difficult to achieve adequate iron intake from unfortified local foods at 6–12 months of age. Fortification (either processed complementary foods or home fortification) is the most feasible option in most circumstances given the cost of iron‐rich foods (such as liver or meat). Adequate zinc and vitamin A intakes can be achieved from local foods, but this requires very careful attention to dietary choices. Fortification can help ensure zinc and vitamin A intakes when nutrient‐rich local foods are costly or unavailable (e.g. seasonally). The results also indicate that fortification can be highly effective at improving iron and vitamin A status. Although this could be accomplished by other strategies, such as iron or vitamin A supplementation, using complementary foods as the vehicle may be less risky [given recent concerns about adverse effects of iron supplements in certain situations (WHO & UNICEF 2007)] and more acceptable to caregivers. Further research is needed to understand why zinc‐fortified foods have generally little effect on plasma zinc concentrations. Complementary feeding interventions, by themselves, cannot change the underlying conditions of poverty and poor sanitation that contribute to child malnutrition. They need to be implemented in conjunction with a larger strategy that includes improved water and sanitation, better health care and adequate housing. Nonetheless, the results of this review indicate that carefully designed programmes that include pre‐tested educational messages provided through multiple channels, with fortified foods or home‐fortification products made available depending on the needs of the target population, can substantially improve growth and micronutrient status and may also reduce morbidity and enhance behavioural development. The key challenge is how to implement high‐quality programmes that are sustainable when delivered on a large scale.
The risk factors for childhood overweight and obesity are known and can be identified antenatally or during infancy, however, the majority of effective interventions are designed for older children. This review identified interventions designed to reduce the risk of overweight/obesity that were delivered antenatally or during the first 2 years of life, with outcomes reported from birth to 7 years of age. Six electronic databases were searched for papers reporting randomised controlled trials of interventions published from January 1990 to September 2013. A total of 35 eligible studies were identified, describing 27 unique trials of which 24 were behavioural and three were non‐behavioural. The 24 behavioural trials were categorised by type of intervention: (1) nutritional and/or responsive feeding interventions targeted at parents of infants, which improved feeding practices and had some impact on child weight (n = 12); (2) breastfeeding promotion and lactation support for mothers, which had a positive effect on breastfeeding but not child weight (n = 5); (3) parenting and family lifestyle (n = 4); and (4) maternal health (n = 3) interventions that had some impact on feeding practices but not child weight. The non‐behavioural trials comprised interventions manipulating formula milk composition (n = 3). Of these, lower/hydrolysed protein formula milk had a positive effect on weight outcomes. Interventions that aim to improve diet and parental responsiveness to infant cues showed most promise in terms of self‐reported behavioural change. Despite the known risk factors, there were very few intervention studies for pregnant women that continue during infancy which should be a priority for future research.
As the World Health Organization (WHO) infant and young child feeding (IYCF) indicators are increasingly adopted, a comparison of country‐specific analyses of the indicators' associations with child growth is needed to examine the consistency of these relationships across contexts and to assess the strengths and potential limitations of the indicators. This study aims to determine cross‐country patterns of associations of each of these indicators with child stunting, wasting, height‐for‐age z‐score (HAZ) and weight‐for‐height z‐score (WHZ). Eight studies using recent Demographic and Health Surveys data from a total of nine countries in sub‐Saharan Africa (nine), Asia (three) and the Caribbean (one) were identified. The WHO indicators showed mixed associations with child anthropometric indicators across countries. Breastfeeding indicators demonstrated negative associations with HAZ, while indicators of diet diversity and overall diet quality were positively associated with HAZ in Bangladesh, Ethiopia, India and Zambia (P < 0.05). These same complementary feeding indicators did not show consistent relationships with child stunting. Exclusive breastfeeding under 6 months of age was associated with greater WHZ in Bangladesh and Zambia (P < 0.05), although CF indicators did not show strong associations with WHZ or wasting. The lack of sensitivity and specificity of many of the IYCF indicators may contribute to the inconsistent associations observed. The WHO indicators are clearly valuable tools for broadly assessing the quality of child diets and for monitoring population trends in IYCF practices over time. However, additional measures of dietary quality and quantity may be necessary to understand how specific IYCF behaviours relate to child growth faltering.
This systematic review investigates the relationship between maternal obesity and breastfeeding intention, initiation, intensity, duration and milk supply. A comprehensive search was performed through three major databases, including Medline, Cochrane Library and Cumulative Index For Nursing and Allied Health Literature, and by screening reference lists of the relevant publications. Selection criteria were: report of original research, studies on low‐risk obese mothers and the comparison with normal weight mothers which met at least two of the following primary outcomes: breastfeeding intention; initiation; intensity; duration and/or milk supply. Furthermore, the included reports had to contain a clear definition of pre‐pregnant obesity, use compensation mechanisms for potential confounding factors, have a prospective cohort design and had to have been published between 1997 and 2011 and in English, French or Dutch. Effects of obesity on breastfeeding intention, initiation, intensity, duration and milk supply were analysed, tabulated and summarised in this review. Studies have found that obese women are less likely to intend to breastfeed and that maternal obesity seems to be associated with a decreased initiation of breastfeeding, a shortened duration of breastfeeding, a less adequate milk supply and delayed onset of lactogenesis II, compared with their normal weight counterparts. This systematic review indicates therefore that maternal obesity is an adverse determinant for breastfeeding success.
Concerns about the increasing rates of obesity in developing countries have led many policy makers to question the impacts of maternal and early child nutrition on risk of later obesity. The purposes of the review are to summarise the studies on the associations between nutrition during pregnancy and infant feeding practices with later obesity from childhood through adulthood and to identify potential ways for preventing obesity in developing countries. As few studies were identified in developing countries, key studies in developed countries were included in the review. Poor prenatal dietary intakes of energy, protein and micronutrients were shown to be associated with increased risk of adult obesity in offspring. Female offspring seem to be more vulnerable than male offspring when their mothers receive insufficient energy during pregnancy. By influencing birthweight, optimal prenatal nutrition might reduce the risk of obesity in adults. While normal birthweights (2500–3999 g) were associated with higher body mass index (BMI) as adults, they generally were associated with higher fat‐free mass and lower fat mass compared with low birthweights (<2500 g). Low birthweight was associated with higher risk of metabolic syndrome and central obesity in adults. Breastfeeding and timely introduction of complementary foods were shown to protect against obesity later in life in observational studies. High‐protein intake during early childhood however was associated with higher body fat mass and obesity in adulthood. In developed countries, increased weight gain during the first 2 years of life was associated with a higher BMI in adulthood. However, recent studies in developing countries showed that higher BMI was more related to greater lean body mass than fat mass. It appears that increased length at 2 years of age was positively associated with height, weight and fat‐free mass, and was only weakly associated with fat mass. The protective associations between breastfeeding and obesity may differ in developing countries compared to developed countries because many studies in developed countries used formula feeding as a control. Future research on the relationship between breastfeeding, timely introduction of complementary feeding or rapid weight gain and obesity are warranted in developing countries. The focus of interventions to reduce risk of obesity in later life in developing countries could include: improving maternal nutritional status during pregnancy to reduce low birthweight; enhancing breastfeeding (including durations of exclusive and total breastfeeding); timely introduction of high‐quality complementary foods (containing micronutrients and essential fats) but not excessive in protein; further evidence is needed to understand the extent of weight gain and length gain during early childhood are related to body composition in later life.
In 2011, one in every four (26%) children under 5 years of age worldwide was stunted. The realization that most stunting cannot be explained by poor diet or by diarrhoea, nor completely reversed by optimized diet and reduced diarrhoea has led to the hypothesis that a primary underlying cause of stunting is subclinical gut disease. Essentially, ingested microbes set in motion two overlapping and interacting pathways that result in linear growth impairment. Firstly, partial villous atrophy results in a reduced absorptive surface area and loss of digestive enzymes. This in turn results in maldigestion and malabsorption of much needed nutrients. Secondly, microbes and their products make the gut leaky, allowing luminal contents to translocate into systemic circulation. This creates a condition of chronic immune activation, which (i) diverts nutrient resources towards the metabolically expensive business of infection fighting rather than growth; (ii) suppresses the growth hormone‐IGF axis and inhibits bone growth, leading to growth impairment; and (iii) causes further damage to the intestinal mucosa thereby exacerbating the problem. As such, the unhygienic environments in which infants and young children live and grow must contribute to, if not be the overriding cause of, this environmental enteric dysfunction. We suggest that a package of baby‐WASH interventions (sanitation and water improvement, handwashing with soap, ensuring a clean play and infant feeding environment and food hygiene) that interrupt specific pathways through which feco‐oral transmission occurs in the first two years of a child's life may be central to global stunting reduction efforts.
Inadequate feeding and care may contribute to high rates of stunting and underweight among children in rural families in India. This cluster‐randomized trial tested the hypothesis that teaching caregivers appropriate complementary feeding and strategies for how to feed and play responsively through home‐visits would increase children's dietary intake, growth and development compared with home‐visit‐complementary feeding education alone or routine care. Sixty villages in Andhra Pradesh were randomized into three groups of 20 villages with 200 mother–infant dyads in each group. The control group (CG) received routine Integrated Child Development Services (ICDS); the complementary feeding group (CFG) received the ICDS plus the World Health Organization recommendations on breastfeeding and complementary foods; and the responsive complementary feeding and play group (RCF&PG) received the same intervention as the CFG plus skills for responsive feeding and psychosocial stimulation. Both intervention groups received bi‐weekly visits by trained village women. The groups did not differ at 3 months on socioeconomic status, maternal and child nutritional indices, and maternal depression. After controlling for potential confounding factors using the mixed models approach, the 12‐month intervention to the CFG and RCF&PG significantly (P < 0.05) increased median intakes of energy, protein, Vitamin A, calcium (CFG), iron and zinc, reduced stunting [0.19, confidence interval (CI): 0.0–0.4] in the CFG (but not RCF&PG) and increased (P < 0.01) Bayley Mental Development scores (mean = 3.1, CI: 0.8–5.3) in the RCF&PG (but not CFG) compared with CG. Community‐based educational interventions can improve dietary intake, length (CFG) and mental development (RCF&PG) for children under 2 years in food‐secure rural Indian families.
Meeting the high nutrient needs of pregnant and lactating women and their young children in regions such as South Asia is challenging because diets are dominated by staple foods with low nutrient density and poor mineral bioavailability. Gaps in nutritional adequacy in such populations probably date back to the agricultural revolution ~10 000 years ago. Options for improving diets during the first 1000 days include dietary diversification and increased intake of nutrient‐rich foods, improved complementary feeding practices, micronutrient supplements and fortified foods or products specifically designed for these target groups. Evidence from intervention trials indicates that several of these strategies, both prenatal and post‐natal, can have a positive impact on child growth, but results are mixed and a growth response is not always observed. Nutrition interventions, by themselves, may not result in the desired impact if the target population suffers from frequent infection, both clinical and subclinical. Further research is needed to understand the mechanisms underlying both prenatal and post‐natal growth restriction. In the meantime, implementation and rigorous evaluation of integrated interventions that address the multiple causes of stunting is a high priority. These intervention packages should ideally include improved nutrition during both pregnancy and the post‐natal period, prevention and control of prenatal and post‐natal infection and subclinical conditions that restrict growth, care for women and children and stimulation of early child development. In regions such as South Asia, such strategies hold great promise for reducing stunting and enhancing human capital formation.
Over the past two decades, there has been a marked shift in the fatty acid composition of the diets of industrialized nations towards increased intake of the n‐6 fatty acid linoleic acid (LA, 18:2n‐6), largely as a result of the replacement of saturated fats with plant‐based polyunsaturated fatty acid (PUFA). While health agencies internationally continue to advocate for high n‐6 PUFA intake combined with increased intakes of preformed n‐3 long‐chain PUFAs (LCPUFA) docosahexaenoic acid (DHA, 22:6n‐3) and eicosapentaenoic acid (EPA, 20:5n‐3) to reduce the incidence of cardiovascular disease (CVD), there are questions as to whether this is the best approach. LA competes with alpha‐linolenic acid (18:3n‐3) for endogenous conversion to the LC derivatives EPA and DHA, and LA also inhibits incorporation of DHA and EPA into tissues. Thus, high‐LA levels in the diet generally result in low n‐3 LCPUFA status. Pregnancy and infancy are developmental periods during which the fatty acid supply is particularly critical. The importance of an adequate supply of n‐3 LCPUFA for ensuring optimal development of infant brain and visual systems is well established, and there is now evidence that the supply of n‐3 LCPUFA also influences a range of growth, metabolic and immune outcomes in childhood. This review will re‐evaluate the health benefits of modern Western diets and pose the question of whether the introduction of similar diets to nations with emerging economies is the most prudent public health strategy for improving health in these populations.
Stunting is a complex and enduring challenge with far‐reaching consequences for those affected and society as a whole. To accelerate progress in eliminating stunting, broader efforts are needed that reach beyond the nutrition sector to tackle the underlying determinants of undernutrition. There is growing interest in how water, sanitation and hygiene (WASH) interventions might support strategies to reduce stunting in high‐burden settings, such as South Asia and sub‐Saharan Africa. This review article considers two broad questions: (1) can WASH interventions make a significant contribution to reducing the global prevalence of childhood stunting, and (2) how can WASH interventions be delivered to optimize their effect on stunting and accelerate progress? The evidence reviewed suggests that poor WASH conditions have a significant detrimental effect on child growth and development resulting from sustained exposure to enteric pathogens but also due to wider social and economic mechanisms. Realizing the potential of WASH to reduce stunting requires a redoubling of efforts to achieve universal access to these services as envisaged under the Sustainable Development Goals. It may also require new or modified WASH strategies that go beyond the scope of traditional interventions to specifically address exposure pathways in the first 2 years of life when the process of stunting is concentrated.