Relations between nutrition and cognition in rural Guatemala

Early Childhood Nutrition and Cognitive Functioning in Childhood and Adolescence

BACKGROUND

The Institute of Nutrition of Central America and Panama (INCAP) Longitudinal Study provides a unique opportunity to examine the role of nutrition in cognitive functioning over time, controlling for other sociocultural factors.

OBJECTIVE

This article describes results of analyses carried out in the INCAP Longitudinal Study on relationships between early childhood nutritional status and supplementation with concurrent and subsequent cognitive development in childhood and adolescence/young adulthood.

METHODS

Articles were chosen for review that addressed this topic from the original and 1988 follow-up studies; 41 articles were reviewed and key results summarized for relationships between early nutrition and cognition in infancy, early childhood, and adolescence/young adulthood.

RESULTS

Overall, results suggest strong relationships between indicators of a child's early nutritional status and motor and cognitive development in infancy and through the preschool years, continuing into adolescence/young adulthood, particularly for males. Nutritional supplementation during gestation through 2 years of age was associated with improvements in motor development and small, but consistent improvements in cognitive development during infancy and preschool years, with similar results of greater magnitude found with cognitive functioning in adolescence and young adulthood. Findings remain strong after controlling for various sociocultural factors (eg, socioeconomic status [SES]) and schooling. Among adolescents, significant interactions were found with SES and years of school attained; differences in performance favored Atole over Fresco children, with greatest differences for participants of low SES and those with higher levels of schooling.

CONCLUSIONS

Results support the need for programs to address unmet nutritional requirements among at-risk mothers and children and potential beneficial effects for human cognitive development.

How Living in Vulnerable Conditions Undermines Cognitive Development: Evidence from the Pediatric Population of Guatemala

Low-socioeconomic backgrounds represent a risk factor for children’s cognitive development and well-being. Evidence from many studies highlights that cognitive processes may be adversely affected by vulnerable contexts. The aim of this study was to determine if living in vulnerable conditions affects childhood cognitive development. To achieve this, we assessed the performance of a sample of 347 Guatemalan children and adolescents aged from 6 to 17 years (M = 10.8, SD = 3) in a series of 10 neuropsychological tasks recently standardized for the pediatric population of this country. Two-fifths of the sample (41.5%) could be considered to have vulnerable backgrounds, coming from families with low-socioeconomic status or having had a high exposure to violence. As expected, results showed lower scores in language and attention for the vulnerable group. However, contrary to expectations, consistent systematic differences were not found in the executive function tasks. Vulnerable children obtained lower scores in cognitive flexibility compared to the non-vulnerable group, but higher scores in inhibition and problem-solving tasks. These results suggest the importance of developing pediatric standards of cognitive performance that take environmental vulnerable conditions into consideration. These findings, one of the first obtained in the Guatemalan population, also provide relevant information for specific educational interventions and public health policies which will enhance vulnerable children and adolescent cognitive development.

Maya K'iche' Food Groups and Implications for Guatemalan Food Guidelines

The anthropology of linguistics, food, and nutrition sciences has a key role with regard to taking a critical look at the Guatemalan Food Guidelines (GFG). These GFG are communicated to native communities to interpret their eating patterns and the structural cognitive interpretation of these food groups in a cultural context. Our understanding of food is informed by cognitive structure represented by language. Since food is fundamental in human cultural identities, understanding food and food categories from the perspective of Mayan indigenous groups should be a fundamental pillar of health, food, and nutrition. The purpose of this research was to explore the GFG and compare them to K'iche' understandings of food groups in terms of cognitive structural similarities and differences. The research was carried out in the field by way of semi-structured interviews and participant observation among K'iche' Mayan families in Nahualá (Western Guatemala) to compare and contrast data collected on K'iche' food groups and corresponding cognitive structure with previously published findings on the GFG. These findings were confirmed through fieldwork, though some of the nuances of subcategories have changed, and significant stress was placed on 2 food groups: wa (corn-based food) and ri'kil (non-corn-based food). The research concludes that the cognitive structure and understanding of food groups and their uses communicated through K'iche' language differ significantly from the hierarchical, technical description of food groups communicated through the GFG. In order to strengthen public health approaches to food and nutrition, indigenous knowledge must be respected, learned, and integrated into GFG.

Prenatal supplementation with DHA improves attention at 5 y of age: a randomized controlled trial

BACKGROUND

Docosahexanoic acid (DHA) is an important constituent of the brain. Evidence from well-designed intervention trials of the long-term benefits of increasing DHA intake during pregnancy has been sparse.

OBJECTIVE

We evaluated global cognition, behavior, and attention at age 5 y in the offspring of Mexican women who participated in a randomized controlled trial of prenatal DHA supplementation.

DESIGN

A total of 1094 women were randomly assigned to receive 400 mg of either DHA or placebo/d from 18 to 22 wk of pregnancy until delivery. We assessed cognitive development and behavioral and executive functioning, including attention, in 797 offspring at age 5 y (82% of 973 live births) with the use of the McCarthy Scales of Children's Abilities (MSCA), the parental scale of the Behavioral Assessment System for Children, Second Edition (BASC-2), and the Conners' Kiddie Continuous Performance Test (K-CPT). We compared the groups on raw scores, T-scores, and standardized scores, as appropriate. We examined heterogeneity by the quality of the home environment, maternal intelligence, and socioeconomic status.

RESULTS

There were no group differences for MSCA scores (P > 0.05), but the positive effect of the home environment at 12 mo on general cognitive abilities was attenuated in the DHA group compared with in the placebo group (P-interaction < 0.05). There were no differences between groups on the BASC-2. On the K-CPT, offspring in the DHA group showed improved mean ± SD T-scores compared with those of the placebo group for omissions (DHA: 47.6 ± 10.3; placebo: 49.6 ± 11.2; P < 0.01) with no differences (P > 0.05) for the other K-CPT scores or of the proportion who were clinically at risk of attention deficit hyperactivity disorders after Bonferroni correction for multiple comparisons.

CONCLUSION

Prenatal exposure to DHA may contribute to improved sustained attention in preschool children. This trial was registered at clinicaltrials.gov as NCT00646360.

Mental Development after Dietary Intervention

In an earlier study it was found that the nutritional status of young, rural Philippine children improved after their diets were supplemented for one year, while the status of nonsupplemented children deteriorated. The current study is concerned with the effects of nutrition on the mental development of those children. Following a year of supplementation (experimental group) and monthly checkups (experimental and control groups), 40 children, 24 girls and 16 boys, responded to the mental scale of the Bayley Scales of Infant Development. While there were differences in nutritional status between the experimental and control groups, there were no significant differences on the measure of mental development. The control group consisted of 2 barrios whose responses were significantly different from one another in an unexpected direction-the barrio with significantly higher Bayley scores had a significantly poorer nutritional status than the other control barrio. These results suggest that there is a complex relationship between nutrition and mental development.

Growth and Cognition in Brazilian Schoolchildren: A Spontaneously Occurring Intervention Study

This study examines the effects of dietary, cultural, and educational intervention on physical growth and cognition in Brazilian children aged from 7 to 10 years. A group of 38 domestic servants' children who had resided and studied for an average of three years in upper-middle class environments were compared with 88 upper-middle class children and 100 slum-dwelling (favela) children using the following measures: weight-for-height, height-for-age, Goodenough-Harris Drawing Test, the Brazilian Non-verbal Intelligence Test (INV), Raven Coloured Progressive Matrices (CPM), WISC-R Coding and Block Design subtest. Although domestic servants' children were significantly taller and heavier than their group of origin (slum-dwelling children) they continued to be significantly shorter than the middle class. Domestic servants' daughters scored significantly better than their slum-dwelling counterparts on cognitive tests measuring speed and accuracy (WISC-R Coding) and analogical reasoning (Raven Coloured Progressive Matrices), however, girls from both lower socioeconomic groups were similar in their performances on the Goodenough-Harris Drawing Test, Non-verbal Intelligence Test (INV), and WISC-R Block Design subtest. Domestic servants' sons were similar to slum-dwelling boys in performance on all cognitive measures. The length of time domestic servants' children had resided in middle class homes was positively and significantly correlated with their weight-for-height and two of the five cognitive tests. Among domestic servants, mothers' egalitarian sex role and less orthodox religious attitudes were positively correlated with children's cognitive performance. The experience of living and studying in a middle class environment resulted in greater gains in physical than in cognitive development.

Linear growth and child development in low- and middle-income countries: a meta-analysis

BACKGROUND AND OBJECTIVE

The initial years of life are critical for physical growth and broader cognitive, motor, and socioemotional development, but the magnitude of the link between these processes remains unclear. Our objective was to produce quantitative estimates of the cross-sectional and prospective association of height-for-age z score (HAZ) with child development.

METHODS

Observational studies conducted in low- and middle-income countries (LMICs) presenting data on the relationship of linear growth with any measure of child development among children <12 years of age were identified from a systematic search of PubMed, Embase, and PsycINFO. Two reviewers then extracted these data by using a standardized form.

RESULTS

A total of 68 published studies conducted in 29 LMICs were included in the final database. The pooled adjusted standardized mean difference in cross-sectional cognitive ability per unit increase in HAZ for children ≤ 2 years old was +0.24 (95% confidence interval [CI], 0.14-0.33; I(2) = 53%) and +0.09 for children > 2 years old (95% CI, 0.05-0.12; I(2) = 78%). Prospectively, each unit increase in HAZ for children ≤ 2 years old was associated with a +0.22-SD increase in cognition at 5 to 11 years after multivariate adjustment (95% CI, 0.17-0.27; I(2) = 0%). HAZ was also significantly associated with earlier walking age and better motor scores (P < .05).

CONCLUSIONS

Observational evidence suggests a robust positive association between linear growth during the first 2 years of life with cognitive and motor development. Effective interventions that reduce linear growth restriction may improve developmental outcomes; however, integration with environmental, educational, and stimulation interventions may produce larger positive effects.

The emerging role of dietary fructose in obesity and cognitive decline

The incidence of obesity has increased dramatically over the past several years, and in parallel, so has the prevalence of type 2 diabetes (T2D). Numerous studies have demonstrated that both obesity and T2D are associated with lower cognitive performance, cognitive decline, and dementia. Intake of dietary fructose has also increased. In fact, high-fructose corn syrup (HFCS) accounts for as much as 40% of caloric sweeteners used in the United States. Given the increase in the incidence of Alzheimer’s disease (AD), characterized by an age-related decline in memory and cognitive functioning, in this report we review the effects of obesity on cognitive performance and the impact of high fructose intake in promoting cognitive decline. The paper then considers the effects of omega-3 fatty acids (FAs), which have been linked to promising results in cognitive function including ameliorating the impact of a high-fructose diet.

Effects of a community-based approach of food and psychosocial stimulation on growth and development of severely malnourished children in Bangladesh: a randomised trial

BACKGROUND/OBJECTIVE

Psychosocial stimulation (PS) and food supplementation (FS) improve development of malnourished children. This study evaluates the effects of a community-based approach of PS and FS on growth and development of severely malnourished children.

SUBJECTS/METHODS

Severely underweight hospitalised children aged 6-24 months (n = 507) were randomly allocated on discharge to five groups: (i) PS, (ii) FS, (iii) PS+FS, (iv) clinic-control and (v) hospital-control. PS included play sessions and parental counselling on child development. This was done at each fortnightly follow-up visit, that is, every second week, for 6 months at community clinics. FS included distribution of cereal-based food packets (150-300 kcal/day) for 3 months. All groups received medical care, micronutrient supplementation, health-education and growth monitoring. Children's development was assessed using revised version of Bayley Scales of Infant Development at baseline and after 3 and 6 months of intervention. Anthropometry was measured using standard procedure.

RESULTS

Comparing groups with any stimulation with those with no stimulation there was a significant effect of stimulation on children's mental development index (group*session interaction P = 0.037, effect size = 0.37 s.d.) and weight-for-age Z-score (group*session interaction P = 0.02, effect size=0.26 s.d.). Poor levels of development and nutritional status were sustained, however, due to their initial very severe malnutrition. There was no effect on motor development and linear growth.

CONCLUSION

Children receiving any stimulation showed a significant benefit to mental development and growth in weight. More intensive intervention with longer duration is needed to correct their poor developmental levels and nutritional status.

A narrative review of physical activity, nutrition, and obesity to cognition and scholastic performance across the human lifespan

We reviewed studies that examine the relationship of energy consumption, storage, and expenditure to cognition and scholastic performance. Specifically, the literature base on nutrient intake, body mass, and physical activity is described relative to cognitive development and academic achievement. The review of literature regarding the overconsumption of energy and excess body mass suggests poorer academic achievement during development and greater decay of brain structure and function accompanied by increased cognitive aging during older adulthood. The review of literature regarding energy expenditure through the adoption of increased physical activity participation suggests increased cognitive health and function. Although this area of study is in its infancy, the preliminary data are promising and matched with the declining physical health of industrialized nations; this area of science could provide insight aimed at improving brain health and cognitive function across the human lifespan.

Early postnatal protein-calorie malnutrition and cognition: a review of human and animal studies

Malnutrition continues to be recognized as the most common and serious form of children's dietary disease in the developing countries and is one of the principal factors affecting brain development. The purpose of this paper is to review human and animal studies relating malnutrition to cognitive development, focusing in correlational and interventional data, and to provide a discussion of possible mechanisms by which malnutrition affects cognition.

INCAP Studies of Malnutrition and Cognitive Behavior

The Institute of Nutrition of Central America and Panama (INCAP) has made major contributions to the study of the effects of malnutrition on learning. This report summarizes work on the relationship of nutrition to children's learning and development from the 1960's through 1998. The Oriente Longitudinal Study examined the effects of two types of supplementation for mothers and young children on their growth and development (an energy-only drink compared with a protein-energy drink) using a quasi-experimental design. Both drinks were supplemented with micronutrients, and were offered daily. As a result of the research on malnutrition and mental development, researchers could conclude by 1993 that supplementary feeding of infants and young children resulted in significant increases cognitive development and school performance through adolescence. The research also suggested that the pathways that link malnutrition with later development are not only through the neurological system but also operate through changes in child behavior which affect the kinds of care children receive. Other research on learning and development showed that families understood the concept of intelligence, demonstrated the link between micronutrients and cognitive development, and documented the amount of wastage or repetition and drop-out that occurs in Guatemalan schools.

Undernutrition, fatty acid and micronutrient status in relation to cognitive performance in Indian school children: a cross-sectional study

While undernutrition and anaemia have previously been linked to poor development of children, relatively little is known about the role of B-vitamins and fatty acids on cognition. The present study aims to explore the associations between indicators of body size, fatty acid and micronutrient status on cognitive performance in 598 Indian school children aged 6-10 years. Baseline data of a clinical study were used to assess these associations by analyses of variance adjusting for age, sex, school, maternal education and cognitive tester. The Kaufman Assessment Battery for Children II was used to measure four cognitive domains, including fluid reasoning, short-term memory, retrieval ability and cognitive speediness. Scores were combined into an overall measure, named mental processing index (MPI). Body size indicators and Hb concentrations were significantly positively related to cognitive domains and MPI, such that increases of 1 sd in height-for-age and weight-for-age z-scores would each translate into a 0.09 sd increase in MPI, P = 0.0006 and 0.002, respectively. A 10 g/l increase in Hb concentrations would translate into a 0.08 sd increase in MPI, P = 0.0008. Log-transformed vitamin B12 concentrations were significantly inversely associated with short-term memory, retrieval ability and MPI (beta (95 % CI) = - 0.124 (- 0.224, - 0.023), P = 0.02). Other indicators of Fe, iodine, folate and fatty acid status were not significantly related to cognition. Our findings for body size, fatty acids and micronutrients were in agreement with previous observational studies. The inverse association of vitamin B12 with mental development was unexpected and needed further study.

Poor psychometric scores of children living in isolated riverine and agrarian communities and fish-methylmercury exposure

Because of heavy dependence on fish, Amazonian riparian communities are chronically exposed to high levels of methylmercury (MeHg). We studied fish-MeHg exposure (total hair-Hg, HHg) as a determinant of neurocognitive scores of children living in two geographically distant, culturally distinct and isolated poor communities of non-urban environments: Amazonian riverines (Riparians, n=38) of the Puruzinho Lake community in the Rio Madeira Basin and rural agrarians from Iúna, Espírito Santo (Agrarians, n=32). Nutritional status was estimated by anthropometry (Z-scores) and individual cognitive abilities were assessed by the Wechsler Intelligence Scale for Children-III (WISC-III) and the Human Figure Drawings (HFD), both validated versions for Brazilian children. Anthropometric assessment showed slightly elevated Z-scores for the Agrarian children (not statistically significant) but median HHg concentrations were 14.4 and 0.25microgg(-1) respectively for Riparian and Agrarian children (p=0.000). Despite paradoxical MeHg exposures, both groups showed comparable HFD scores but very poor performance in WISC-III test battery; median of sum of WISC-III subtests scores (SigmaTOT) were 17.9 and 28.6 (p<0.000) for Riparian and Agrarian children, respectively (percentage scale). Spearman correlation between nutritional status (attained growth) and psychometric scores were statistically significant between height-for-age Z-score and Object Assembly subtest (r=0.269; p=0.043), SigmaTOT (r=0.319; p=0.016), Performance-IQ (r=0.311; p=0.019) and Perceptual Organization Index scores (r=0.302; p=0.023). In these isolated communities there are stronger determinants of neurocognitive poor performance than MeHg exposure. Global strategies for reducing human exposure to MeHg by curtailing fish consumption are unrealistic options for riverine subsistence populations and are not justifiable to prevent low cognitive scores.

The influence of feeding patterns on head circumference among Turkish infants during the first 6 months of life

The influence of various feeding patterns on physical growth and mental development of the infant, particularly during the first 6 months of life, is an important subject. Head circumference values of 172 healthy new-born infants were included in the study; 62 were exclusively breast-fed (BF), 58 were mixed-fed (MF) and 52 were formula-fed (FF). No significant differences were found in head circumference values between the groups at birth (BF 35.2+/-0.1, MF 35.1+/-0.1, FF 35.0+/-0.1 cm for boys and BF 35.0+/-0.1, MF 34.9+/-0.1, FF 34.8+/-0.1 cm for girls). At the end of the first month, the infants in the BF group (38.3+/-0.1 cm and 37.9+/-0.1 cm for boys and girls, respectively) had strikingly greater head circumference measurements than the others (MF 36.7+/-0.1, FF 36.6+/-0.1 cm for boys and MF 36.5+/-0.1, FF 36.4+/-0.1 cm for girls) (P < 0.05). However, in the subsequent 4-month period, the values detected in each group were almost the same. At the sixth month, head circumference-for-age values of infants in MF (42.6+/-0.1 cm for boys, 41.4+/-0.1 cm for girls) and FF (42.5+/-0.1 cm for boys, 41.5+/-0.1 cm for girls) were well below those of BF group (43.7+/-0.1 cm and 42.9+/-0.1 cm for boys and girls, respectively) and the standard curve (P < 0.05). These results suggest that exclusive breast feeding is sufficient during the first 6 months, the most important period of life.

Predicting treatment-seeking behavior in Guatemala: a comparison of the health services research and decision-theoretic approaches

This study attempts to identify and describe factors associated with the choice of a health care source in rural Guatemala. Because of limited choice options, rural Guatemala makes an excellent location for studying the factors that affect utilization patterns. Illness case histories were collected from a random sample of 270 households in six villages. Then, two different methodological approaches were used to predict treatment actions. First, a sociobehavioral model, which encompasses enabling, predisposing, and need factors, was used to predict treatment choices. Using discriminant analysis we identified factors associated with the use of home remedies, a pharmacy, the health post, a physician, or folk healer. In a second, parallel study, descriptive interviews were used to identify important factors in choosing a treatment strategy. From these interviews, and from responses to hypothetical illness cases, we developed a decision model of treatment actions. Both models were tested against the set of illness cases. Results indicate that both approaches identify similar variables (especially, severity), although selection of variables through the multivariate analysis was much more successful in predicting treatment actions.

Frequent diarrhoeas in early childhood have sustained effects on the height, weight and head circumference of children in East Bhutan

Episodes of diarrhoea and nutritional status of 113 children in East Bhutan were recorded monthly from 7 to 36 months of age. A re-examination was carried out 20 months later. The load of diarrhoeal diseases in early childhood was negatively associated with the parameters of children's long-term nutritional status 20 months later. Also, when early nutritional status and socioeconomic factors are included in the model, the diarrhoea variable explains a significant part of the variation in height for age (p = 0.04, delta R2 = 0.035), weight for age (p = 0.03, delta R2 = 0.030) and head circumference (p = 0.0007, delta R2 = 0.077). This is not so for the variation in weight for height or mid-upper arm circumference (p > 0.1, delta R2 < 0.005). Stunting is widespread in the area, and the effects of diarrhoea on nutritional status are more likely to be sustained in settings where dietary intake is marginal.

Economic advantage and the cognitive ability of rural children in Zaire

Rural Zairian children (n = 32), 4 to 6 years old, were enrolled in a preschool educational and nutritional enrichment program throughout the school year. As part of the evaluative research for this program, cognitive and motor development of the children was assessed with the American Guidance Service (AGS) Early Childhood Screening Profiles (ECSP; Harrison et al., 1990) battery, adapted to the local Bantu dialect of Kituba. On the ECSP global indicator of cognitive ability, the children in the enrichment program performed significantly better than their counterparts in nearby villages, although the two groups did not differ significantly on motor development or anthropometric indicators of physical development. The results indicate that rural African children with reasonable nutritional status demonstrate significantly improved intellectual development in response to a comprehensive economic enhancement and educational enrichment program for them and their families.

A comparative study of black South African children from three different contexts

This study compares family characteristics and developmental outcomes of black children (N = 300) from 3 rural contexts in South Africa: the homeland, the resettlement, and the white-owned farms. Parents in the homeland were more likely to be married and had more education, less household crowding, and lower mobility than parents in the other 2 areas, and higher occupational status than parents from the farms. Child outcomes paralleled these differences in material resources and family stability. Children from the homeland scored higher than children from the resettlement or farms on head circumference, vocabulary, quantitative skill, and self-concept, with no significant differences between the latter 2 areas on these outcome variables. Children from the homeland also scored higher than resettlement children on weight, copying skill, and height, with children from the farms measuring lowest on height. Child outcomes were highly intercorrelated in all 3 residence areas, but correlations among family variables, and between family and child variables, showed different patterns across areas. Parent education, occupation, and crowding were the most consistent predictors of physical development, cognitive development, and self-concept. Family mobility and marital status, however, showed different relationships to other family variables and to child outcomes across the 3 environments. These results highlight the importance of studying children in multiple environmental contexts, because family characteristics are not associated uniformly across residence areas.

Physical size, school performance, and visual-motor maturity in the Philippines

The broad theoretical issue approached in this work is whether supposedly adaptive or maladaptive biological variation has any real impact on people's lives and well-being. From a poor barrio of a rural lowland Philippine fishing community, a sample of 25 boys and 25 girls who had completed first grade at 8 years was measured. This population may be considered moderately undernourished by NCHS but not Philippine standards. Correlations between anthropometry, school grades, and visual-motor skills were calculated. Grades, taken here to have both cognitive and social-behavioral components, correlated best to percentage of median height (NCHS and Philippine), less strongly but still significantly to visual motor skill, and not to weight for height. Visual-motor skills (estimated by the Beery VMI) did not correlate to anthropometry. Visual-motor performance, however, is low by U.S. standards, a finding discussed in a behavioral context.

Nutrition and cognitive development among rural Guatemalan children

Women and children from four Guatemalan villages participated in a voluntary food supplementation program for seven years. In two of the villages, they received a vitamin and mineral fortified, high-protein calorie supplement. In the other two villages, the vitamin-mineral fortified supplement contained no protein and a relatively small number of calories. Cognitive tests were administered regularly to children ages three to seven, and anthropometric measures obtained. In addition, measures of families' social milieu were collected at several points in time. Using multiple regression analysis, we find that both nutritional and social environmental measures are related to various dimensions of cognitive competence. The results suggest that nutritional intake, independent of social factors, affects cognitive development. There is also some evidence that the children who receive the high-protein calorie supplement (and whose mothers received it during pregnancy and lactation) are more likely to score high in cognitive performance. Our results, while not diminishing social environmental explanations of differences in cognitive function, suggest benefits from nutrition intervention programs in rural areas of lesser-developed countries.