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.
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.
It is well known that the relationship between child nutrition and infection is bidirectional, i.e. frequent illness can impair nutritional status and poor nutrition can increase the risk of infection. What is less clear is whether infection reduces the effectiveness of nutrition interventions or, vice versa, whether malnutrition lessens the impact of infection control strategies. The objective of this paper is to review the evidence regarding this interaction between nutrition and infection with respect to child growth in low‐income populations. Even when there are no obvious symptoms, physiological conditions associated with infections can impair growth by suppressing appetite, impairing absorption of nutrients, increasing nutrient losses and diverting nutrients away from growth. However, there is little direct evidence that nutrition interventions are less effective when infection is common; more research is needed on this question. On the other hand, evidence from four intervention trials suggests that the adverse effects of certain infections (e.g. diarrhoea) on growth can be reduced or eliminated by improving nutrition. Interventions that combine improved nutrition with prevention and control of infections are likely to be most effective for enhancing child growth and development.
Understanding of the importance of dietary fatty acids has grown beyond a simple source of energy to complex roles in regulating gene expression and cell and intracellular communication. This is important because the metabolic and neuroendocrine environment of the fetus and infant plays a key role in guiding the set point of neural receptors that regulate energy homeostasis and expression of genes that control energy storage and oxidation. Early deviations in these pathways have the potential to lead to lasting adaptations, termed metabolic programming, which may combine to increase the risk of metabolic syndrome in later life. The quality of fatty acids in human diets has undergone major changes in the last 50 years, characterized by an increase in ω ‐6 and decrease in ω ‐3 fatty acids. Evidence is accumulating to support the concept that the maternal intake of ω ‐6 and ω ‐3 fatty acids in gestation and lactation, possibly involving both excess ω ‐6 and inadequate ω ‐3 fatty acids, can impact the developing infant tissue lipids and neuroendocrine and metabolic pathways relevant to metabolic programming. Further work is needed to understand the needs for different ω ‐6 and ω ‐3 fatty acids during fetal and infant life, and their roles with respect to development of energy homeostasis and metabolism.
Blood and tissue contents of polyunsaturated fatty acid (PUFA) and long‐chain PUFA (LC‐PUFA) are related to numerous health outcomes including cardiovascular health, allergies, mental health and cognitive development. Evidence has accumulated to show that in addition to diet, common polymorphisms in the fatty acid desaturase ( FADS ) gene cluster have very marked effects on human PUFA and LC‐PUFA status. Recent results suggest that in addition to fatty acid desaturase 1 and fatty acid desaturase 2 , the gene product of fatty acid desaturase 3 is associated with desaturating activity. New data have become available to show that FADS single nucleotide polymorphisms (SNPs) also modulate docosahexaenoic acid status in pregnancy as well as LC‐PUFA levels in children and in human milk. There are indications that FADS SNPs modulate the risk for allergic disorders and eczema, and the effect of breastfeeding on later cognitive development. Mechanisms by which FADS SNPs modulate PUFA levels in blood, breast milk and tissues should be explored further. More studies are required to explore the effects of FADS gene variants in populations with different ethnic backgrounds, lifestyles and dietary habits, and to investigate in greater depth the interaction of gene variants, diet and clinical end points, including immune response and developmental outcomes. Analyses of FADS gene variants should be included into all sizeable cohort and intervention studies addressing biological effects of PUFA and LC‐PUFA in order to consider these important confounders, and to enhance study sensitivity and precision.
Omega‐3 and omega‐6 fatty acids, particularly docosahexaenoic acid (DHA), are known to play an essential role in the development of the brain and retina. Intakes in pregnancy and early life affect growth and cognitive performance later in childhood. However, total fat intake, alpha‐linolenic acid (ALA) and DHA intakes are often low among pregnant and lactating women, infants and young children in developing countries. As breast milk is one of the best sources of ALA and DHA, breastfed infants are less likely to be at risk of insufficient intakes than those not breastfed. Enhancing intake of ALA through plant food products (soy beans and oil, canola oil, and foods containing these products such as lipid‐based nutrient supplements) has been shown to be feasible. However, because of the low conversion rates of ALA to DHA, it may be more efficient to increase DHA status through increasing fish consumption or DHA fortification, but these approaches may be more costly. In addition, breastfeeding up to 2 years and beyond is recommended to ensure an adequate essential fat intake in early life. Data from developing countries have shown that a higher omega‐3 fatty acid intake or supplementation during pregnancy may result in small improvements in birthweight, length and gestational age based on two randomized controlled trials and one cross‐sectional study. More rigorous randomized controlled trials are needed to confirm this effect. Limited data from developing countries suggest that ALA or DHA supplementation during lactation and in infants may be beneficial for growth and development of young children 6–24 months of age in these settings. These benefits are more pronounced in undernourished children. However, there is no evidence for improvements in growth following omega‐3 fatty acid supplementation in children >2 years of age.
Determining early-life risk factors for obesity in later life is essential in order to effectively target preventative interventions to reduce obesity. The aim of this systematic review was to investigate current evidence to determine whether the timing of introducing solid foods is associated with obesity in infancy and childhood. Relevant randomized and observational studies from developed countries were identified by searching the following six bio-medical databases (Medline, Embase, British Nursing Index, CINAHL, Maternity and Infant Care, and PsycINFO) and hand-searching reference lists. Studies of pre-term or low birthweight infants were excluded. Twenty-four studies met the inclusion criteria for the systematic review. Data from over 34 000 participants were available for interpretative analysis. No clear association between the age of introduction of solid foods and obesity was found. It is likely that a whole family approach to obesity prevention will be most effective and health professionals should continue to promote healthy infant feeding in line with national recommendations.
With increasing interest in the potential effects of n‐6 and n‐3 fatty acids in early life, there is a need for data on the dietary intake of polyunsaturated fatty acids (PUFA) in low‐income countries. This review compiles information on the content in breast milk and in foods that are important in the diets of low‐income countries from the few studies available. We also estimate the availability of fat and fatty acids in 13 low‐income and middle‐income countries based on national food balance sheets from the United Nations' Food and Agriculture Organization Statistical Database (FOASTAT). Breast milk docosahexaenoic acid content is very low in populations living mainly on a plant‐based diet, but higher in fish‐eating countries. Per capita supply of fat and n‐3 fatty acids increases markedly with increasing gross domestic product (GDP). In most of the 13 countries, 70–80% of the supply of PUFA comes from cereals and vegetable oils, some of which have very low α ‐linolenic acid (ALA) content. The total n‐3 fatty acid supply is below or close to the lower end of the recommended intake range [0.4%E (percentage of energy supply)] for infants and young children, and below the minimum recommended level (0.5%E) for pregnant and lactating women in the nine countries with the lowest GDP. Fish is important as a source of long‐chain n‐3 fatty acids, but intake is low in many countries. The supply of n‐3 fatty acids can be increased by using vegetable oils with higher ALA content (e.g. soybean or rapeseed oil) and by increasing fish production (e.g. through fish farming).
Breastfeeding is a practice which is promoted and scrutinized in the UK and internationally. In this paper, we use interpretative phenomenological analysis to explore the experiences of eight British first‐time mothers who struggled with breastfeeding in the early post‐partum period. Participants kept audio‐diary accounts of their infant feeding experiences across a 7‐day period immediately following the birth of their infant and took part in related semi‐structured interviews a few days after completion of the diary. The overarching theme identified was of a tension between the participants' lived, embodied experience of struggling to breastfeed and the cultural construction of breastfeeding as ‘natural’ and trouble‐free. Participants reported particular difficulties interpreting the pain they experienced during feeds and their emerging maternal identities were threatened, often fluctuating considerably from feed to feed. We discuss some of the implications for breastfeeding promotion and argue for greater awareness and understanding of breastfeeding difficulties so that breastfeeding women are less likely to interpret these as a personal shortcoming in a manner which disempowers them. We also advocate the need to address proximal and distal influences around the breastfeeding dyad and, in particular, to consider the broader cultural context in the UK where breastfeeding is routinely promoted yet often constructed as a shameful act if performed in the public arena.
Undernutrition is associated with poor cognitive development, late entry into school, decreased years of schooling, reduced productivity and smaller adult stature. We use longitudinal data from 1674 Peruvian children participating in the Young Lives study to assess the relative impact of early stunting (stunted at 6–18 months of age) and concurrent stunting (stunted at 4.5–6 years of age) on cognitive ability. Anthropometric data were longitudinally collected for children at 6–18 months of age and 4.5–6 years of age at which time verbal and quantitative ability were also assessed. We estimate that an increase in concurrent height‐for‐age z‐scores (HAZ) by one standard deviation was associated with an increase in a child's score on the Peabody Picture Vocabulary Test (PPVT) by 2.35 points [confidence interval (CI): 1.55–3.15] and a 0.16 point increase on the cognitive development assessment (CDA) (CI: 0.05–0.27). Furthermore, we report that the estimate for concurrent HAZ and PPVT is significantly higher than the estimate for early stunting and PPVT. We found no significant difference between early and concurrent estimates for HAZ and CDA. Children from older mothers, children whose mothers had higher education levels, children living in urban areas, children who attended pre‐school, children with fewer siblings and children from wealthier backgrounds scored higher on both assessments. Cognitive skills of children entering school were associated with early stunting but the strongest association was found with concurrent stunting suggesting that interventions preventing linear growth faltering should not only focus on the under 2s but include children up to 5 years of age.
While adults' energy intake misreporting is a well‐documented phenomenon, relatively little is known about the nature and extent of misreporting among children and adolescents. Children's and adolescents' dietary reporting patterns are likely to be distinct because of their ongoing cognitive and social development. These developmental differences present unique challenges to aspects of dietary reporting, such as food knowledge, portion size estimation and response editing. This review of 28 articles describes energy intake misreporting among children and adolescents. Like adults, children and adolescents tended to underreport energy, with the largest biases observed with food records. Even when mean reported energy intake was close to its expected value, approximately half of all individuals were classified as misreporters, and overreporting appeared to be more common than it is among adults. Associations between numerous characteristics and misreporting were explored in the literature, with the most consistent findings for age and adiposity. Two predictors for adults, gender and social desirability, were not consistent factors among children and adolescents. The review concludes by highlighting knowledge gaps and recommendations for future research and practice.
Inadequate micronutrient intake during pregnancy, lactation and infancy is a major problem in many developing countries. Lipid‐based nutrient supplements (LNS) can improve micronutrient status, growth and development of infants, and also have potential to improve nutritional status of pregnant and lactating women. The objective of the study was to test the acceptability of LNS designed for infants (LNS‐20gM) and pregnant or lactating women (LNS‐P&L). Participants were infants ( n = 22, mean age = 8 months) and pregnant or lactating women ( n = 24) attending routine services at a hospital in Ghana. Infants consumed 45 g of a test meal consisting of one part LNS‐20gM and three parts fermented maize porridge, while women consumed 50 g of a similar test meal containing LNS‐P&L instead. Participants also used their respective LNS at home for 14 days. Primary outcome was the proportion of the test meal consumed. On average, infants consumed 76.2% of the test meal [95% (confidence interval) CI: 65.7, 86.7], while women consumed 87.1% (95% CI: 82.6, 91.6). During the 14‐day period, median daily consumption of LNS‐20gM was 19.3 g, very close to the recommended 20 g d −1 , while that of LNS‐P&L was one sachet, as recommended. We conclude that LNS‐20gM and LNS‐P&L were well accepted.
The present review of determinants of infant fatty acid status was undertaken as part of a conference on ‘Fatty acid status in early life in low‐income countries: determinants and consequences’. Emphasis is placed on the essential fatty acids, and particularly the physiologically important long chain polyunsaturated fatty acids (LCPUFAs) of 20 and 22 carbons. We are unaware of any studies of determinants of infant fatty acid status in populations with a cultural dietary pattern with low amounts of linoleic acid (LA, 18:2 n ‐6) and α ‐linolenic acid (ALA,18:3 n ‐3). Many reports suggest that there may be adverse health effects related to the increased proportion of LA in relation to ALA, which have occurred worldwide due to the increased availability of vegetable oils high in LA. The issue of dietary n‐ 6 to n‐ 3 balance may apply to infant fatty acid status both during fetal and post‐natal life; however, this review focuses on the n‐ 3 and n‐ 6 LCPUFA, in particular, docosahexaenoic acid (DHA, 22:6 n ‐3) and arachidonic acid (AA, 20:4 n ‐6), which are the predominant n‐ 3 and n‐ 6 LCPUFA found in cell membranes. The evidence that these fatty acids are preferentially transferred from maternal to fetal circulation across the placenta, and the sources and mechanisms for this transfer, are reviewed. We also address the sources of DHA and AA for the newborn including human milk DHA and AA and the factors that influence maternal DHA status and consequently the amount of DHA available for transfer to the fetus and infant via human milk.
An alternative to traditional weaning methods known as baby-led weaning (BLW) appears to be emerging in the UK. This approach advocates bypassing typical weaning practices of spoon-feeding pureed foods or baby rice, encouraging instead the introduction of foods in their whole form to the infant from 6 months old. A key tenet of BLW is self-feeding. Anecdotally, the practice of BLW appears to be gaining in popularity. However, research evidence is scant, and little is known about the nature of BLW and the demography of those who utilize it. This study aimed to characterize a sample of women who have chosen to adopt the BLW method and to describe associated attitudes and behaviours. Six hundred and fifty five mothers with a child between 6 months and 12 months of age provided information about timing of weaning onset, use of spoon-feeding and purees, and experiences of weaning and mealtimes. Those participants who used a BLW method reported little use of spoon-feeding and purees and were more likely to have a higher education, higher occupation, be married and have breastfed their infant. BLW was associated with a later introduction of complementary foods, greater participation in meal times and exposure to family foods. Levels of anxiety about weaning and feeding were lower in mothers who adopted a BLW approach. These findings provide an insight into BLW practices and the characteristics of a small population of users.
Many studies have been conducted to investigate the effect of n‐3 long‐chain polyunsaturated fatty acid (LCPUFA) supplementation during the perinatal period on the growth and neurobehavioural development of young children. Most of these intervention trials have involved infants from high‐income countries, and a significant proportion have investigated supplementation of infant formulas. Generally, supplementation of infant formula for preterm rather than term infants has demonstrated more consistent, positive effects on aspects of neurobehavioural development, while the growth of both term and preterm infants appears unaffected by LCPUFA supplementation. Maternal n‐3 LCPUFA supplementation during pregnancy has consistently resulted in modest increases in birth size, and the most recent study suggests that this is also true from women from low‐income environments. The effect of maternal supplementation on global neurobehavioural outcomes for children born at term remains unclear, although n‐3 LCPUFA supplementation of women expressing milk for their preterm infants does improve their performance on tests of global neurodevelopment. Further work is required to determine whether dietary n‐3 LCPUFA is neuroprotective for children from disadvantaged or low‐income backgrounds.
Latinas experience high rates of poverty, household food insecurity and prenatal depression. To date, only one USA study has examined the relationship between household food insecurity and prenatal depression, yet it focused primarily on non‐Latina white and non‐Latina black populations. Therefore, this study examined the independent association of household food insecurity with depressive symptoms among low‐income pregnant Latinas. This cross‐sectional study included 135 low income pregnant Latinas living in Hartford, Connecticut. Women were assessed at enrolment for household food security during pregnancy using an adapted and validated version of the US Household Food Security Survey Module. Prenatal depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale. A cut‐off of ≥21 was used to indicate elevated levels of prenatal depressive symptoms (EPDS). Multivariate backwards stepwise logistic regression was used to identify risk factors for EPDS. Almost one third of participants had EPDS. Women who were food insecure were more likely to experience EPDS compared to food secure women (OR = 2.59; 95% CI = 1.03–6.52). Being primiparous, experiencing heartburn and reporting poor/fair health during pregnancy, as well as having a history of depression were also independent risk factors for experiencing EPDS. Findings from this study suggest the importance of assessing household food insecurity when evaluating depression risk among pregnant Latinas.
Fortified beverages and supplementary foods, when given during pregnancy, have been shown to have positive effects on preventing maternal anaemia and iron deficiency. Studies show that use of micronutrient fortified supplementary foods, especially those containing milk and/or essential fatty acids during pregnancy, increase mean birthweight by around 60–73 g. A few studies have also shown that fortified supplementary foods have impacts on increasing birth length and reducing preterm delivery. Fortification levels have ranged generally from 50% to 100% of the recommended nutrient intake (RNI). Iron, zinc, copper, iodine, selenium, vitamins A, D, E, C, B1, B2, B6, and B12, folic acid, niacin and pantothenic acid are important nutrients that have been included in fortified beverages and supplemental foods for pregnant and lactating women. While calcium has been shown to reduce the risk of pre‐eclampsia and maternal mortality, calcium, phosphorus, potassium, magnesium and manganese can have negative impacts on organoleptic properties, so many products tested have not included these nutrients or have done so in a limited way. Fortified food supplements containing milk and essential fatty acids offer benefits to improving maternal status and pregnancy outcome. Fortified beverages containing only multiple micronutrients have been shown to reduce micronutrient deficiencies such as anaemia and iron deficiency.
Scores of animal studies demonstrate that seed oils replete with linoleic acid and very low in linolenic acid fed as the exclusive source of fat through pregnancy and lactation result in visual, cognitive, and behavioural deficits in the offspring. Commodity peanut, sunflower, and safflower oils fed to mother rats, guinea pigs, rhesus monkeys, and baboons induce predictable changes in tissue polyunsaturated fatty acid composition that are abnormal in free‐living land mammals as well as changes in neurotransmitter levels, catecholamines, and signalling compounds compared with animals with a supply of ω 3 polyunsaturated fatty acid. These diets consistently induce functional deficits in electroretinograms, reflex responses, reward or avoidance induced learning, maze learning, behaviour, and motor development compared with ω 3 replete groups. Boosting neural tissue docosahexaenoic acid (DHA) by feeding preformed DHA enhances visual and cognitive function. Though no human randomized controlled trials on minimal ω 3 requirements in pregnancy and lactation have been conducted, the weight of animal evidence compellingly shows that randomizing pregnant or lactating humans to diets that include high linoleate oils as the sole source of fat would be frankly unethical because they would result in suboptimal child development. Increasing use of commodity ω 3‐deficient oils in developing countries, many in the name of heart health, will limit brain development of the next generation and can be easily corrected at minimal expense by substituting high oleic acid versions of these same oils, in many cases blended with small amounts of α ‐linolenic acid oils like flax or perilla oil. Inclusion of DHA in these diets is likely to further enhance visual and neural development.
We sought to assess the relationship between acculturative type and breastfeeding outcomes among low‐income Latinas, utilising a multidimensional assessment of acculturation. We analysed data derived from a breastfeeding peer counselling randomised trial. Acculturation was assessed during pregnancy using a modified Acculturation Rating Scale for Mexican Americans scale. Analyses were restricted to Latinas who completed the acculturation scale and had post‐partum breastfeeding data ( n = 114). Cox survival analyses were conducted to evaluate differences in breastfeeding continuation and exclusivity by acculturative type. Participants were classified as integrated‐high (23.7%, n = 27), traditional Hispanic (36.8%, n = 42), integrated‐low (12.3%, n = 14) and assimilated (27.2%, n = 31). The integrated‐low group was significantly more likely to continue breastfeeding than the traditional Hispanic, assimilated, and integrated‐high groups ( P < 0.05, P < 0.05, and P < 0.01, respectively). The traditional Hispanic group was marginally more likely to continue breastfeeding than the integrated‐high group ( P = 0.06). Breastfeeding continuation rates vary significantly between acculturative types in this multinational, low‐income Latina sample. Multidimensional assessments of acculturation may prove useful in better tailoring future breastfeeding promotion interventions.
The baby-led weaning philosophy proposes that when solids are introduced, infants should be encouraged to self-feed with solid food, as opposed to spoon-feeding purees. We used data from the Gateshead Millennium Study (GMS) to define the range of ages at which infants reach out for and eat finger foods and related this to developmental status. GMS recruited infants shortly after birth and followed them prospectively using postal questionnaires. Of the 923 eligible children, 602 had data on when they first reached out for food, and 340 (56%) had done so before age 6 months, but 36 (6%) were still not reaching for food at age 8 months. Infants who had not reached out for food by 6 months were less likely to be walking unaided at age 1 year (85 out of 224, 38%) compared with those who did (155 out of 286, 54%; P < 0.001). For the 447 parents who completed a diary of the first five occasions when their child ate finger foods, the first finger food eaten was before age 6 months for 170 (40%) and before age 8 months for 383 (90%); foods offered were mainly bread, rusks or biscuits. Of the 604 with information at age 8 months about current intake, all but 58 (9.6%) were having some finger foods at least daily, but only 309 (51%) were having them more than once per day. Baby-led weaning is probably feasible for a majority of infants, but could lead to nutritional problems for infants who are relatively developmentally delayed.