Avanelle Kirksey

Neuronal Development in Vitamin B6 Deficiency

The morphological changes observed in developing brain regions associated with maternal vitamin B6 deficits are summarized in Table 4. Brain development is a complex and orderly process consisting of cell division, proliferation, migration, and maturation. In the rat, vitamin B6 deficits imposed in utero and up to 30 days postnatal interfere with this orderly process. Deficits of the vitamin imposed in utero have been associated with reduced numbers of total and normal neurons in neocortex and with increased shrunken neurons (700-1500% of controls) in this region. These changes reflect the critical role of vitamin B6 in both neurogenesis and neuron longevity in neocortex. Postnatal cellular events in the neocortex, that is, neuron differentiation and synaptogenesis, were also altered by vitamin B6 deficits; higher order dendrites were reduced on stellate neurons in Layer II and on pyramidal neurons in Layer V. Synaptic density was less in the neutrophil of neocortex and in caudate/putamen, but structural integrity of the synapse was maintained. In cerebellum, both the molecular and granular areas were reduced, the monolayer organization of Purkinje cells was disrupted, and dendritic arborization of the cells was decreased. The number of myelinated axons, as determined by electron microscopy, was decreased in the mediodorsal portion of the pyramidal tract in the medulla oblongata as well as the specific activity of myelination of the total brain. Thus the functional consequences of vitamin B6 deficits during neuronal development may be through reduced connections among neurons and decreased myelination, which alter the rate and magnitude of transmission of nerve impulses.

Nutritional Intake and Context as Predictors of Cognition and Adaptive Behaviour of Egyptian School-age Children:

Relations between nutrition, cognition, and adaptive behaviour measures were assessed for 110 Egyptian pre-adolescents (47% male), ranging in age from 7 to 10 years. Using a combination of oral recall and weighing of food portions, the level of dietary intake was obtained for 19 specific nutrients, including measures of energy (kilocalories), macronutrients (protein, fat, carbohydrates), and micronutrients (vitamins, trace minerals). Children were tested on six subscales from the Egyptian version of the WISC-R plus the Ravens coloured matrices. Based on repeated naturalistic observations we also obtained measures of the childrens behaviour in the school classroom, social interactions with peers and adults, activity level, and affect. Teacher ratings of the childrens classroom behaviour were also obtained. The results indicated that specific nutritional indices were significantly related to male classroom behaviour and activity level, and to female verbal ability and classroom involvement. Although a diverse group of nutrients predicted developmental outcomes, common to many of these nutrients was the fact that they were derived from intake of animal source foods. The results further indicated that relations between nutrition and childrens cognition and behaviour were mediated by contextual factors, such as social class and cultural expectations about the appropriateness of given behaviours.

Variation in zinc, calcium, and magnesium concentrations of human milk within a 24-hour period from 1 to 6 months of lactation

Longitudinal changes in nutrient levels of human milk have been observed with the progression of lactation, but less is known about changes at different feedings during a 24-h period. In this study, calcium, magnesium, and zinc levels were examined in milk obtained from 49 women at every breast feeding during one 24-h period each month for the first 6 months of lactation. Magnesium and zinc concentrations showed significant diurnal variation at each stage of lactation examined, whereas calcium levels were relatively constant. Maximum variations of 7.5, 17, and 48% were observed within a 24-h period in mean levels of calcium, magnesium, and zinc, respectively. Irrespective of variability, zinc and magnesium concentrations in a single milk sample obtained between 10:00 a.m. and 2:00 p.m. were highly correlated with the mean value of samples collected at each feeding during a 24-h period.

Relations between nutrition and cognitive performance in Egyptian toddlers.

n Two relatively unexplored questions--which specific components of chronic mild child malnutrition are associated with specific behavioral and cognitive deficits and do psychosocial child rearing factors moderate the nutrition-development relationship?--were investigated in a longitudinal study involving 153 toddlers from the Egyptian village of Kalama. Beginning at study entry at age 18 months and continuing until 30 months, food intake information was obtained for 2 consecutive days each month. During the same period, researchers visited the homes twice a month to observe both toddler behavior and caregiver styles. Finally, standardized infant development tests were administered at 24 months and 30 minutes and the capacity for exploratory, symbolic play was assessed. Specific components of nutritional intake at 18-23 months of age were confirmed to be uniquely related to specific developmental outcomes at 24 months of age. Changes in toddler intake from 18-30 months also predicted 30-month cognitive performance. At 24 months, general mental competence was associated positively with fat intake, total kilocalories, and total protein intake while symbolic play capacity was related only to total protein intake. Significant increases in predictive variance occurred when the model was expanded to encompass caregiver behaviors as well as nutritional factors. For example, when nonverbal response to child vocalizations was used as the environmental measure, there was evidence of both coactive and synergistic interactions for comparisons involving cognitive development indicators. For symbolic play, an increase in predictive variance was found when the model included the multiplicative interaction of animal kilocalories by nonverbal response to vocalizations. Also observed was a buffering effect against poor psychosocial rearing conditions given the presence of adequate nutritional intake. These findings suggest the feasibility of multidimensional risk profiles, the provision of specific nutrients targeted at specific deficits, and multidisciplinary interventions.n

Effect of short-term oral zinc supplementation on theconcentration of zinc in milk from american and egyptian women

Abstract Investigations of the effects of oral zinc supplementation on levels of zinc in human milk have resulted in contrasting observations. In the present study this relationship was examined in milk of 33 urban American and 30 rural Egyptian women. Of these subjects, 16 Americans and 15 Egyptians were supplemented with 50 mg zinc daily for 34 days at the 7–9th month stage of lactation and zinc levels in their milk were compared to those of their unsupplemented counterparts. Initially zinc concentrations of milk were not significantly different among the four groups; during the study period the concentrations decreased in all groups. Supplemented American women showed significantly less decrease (4%) than their unsupplemented counterparts (25%). Among Egyptian women, supplemented and unsupplemented groups showed similar decreases (8–9%) in zinc concentrations of milk.

A micromethod for determination of plasma pyridoxal phosphate and its use in assessment of storage stability of the vitamer.

A widely used macromethod employing tyrosine apodecarboxylase for measurement of pyridoxal phosphate (PLP) concentration in 0.5–1.0-ml plasma was modified to a microscale utilizing 0.1-ml plasma. Mean PLP levels in 12 plasma samples were 160.6 ± 32.8 pmol/ml (mean ± SD) when analyzed by the macro-method, and were not significantly different compared to those obtained by the micromethod (158.4 ± 28.2 pmol/ ml). Results of the two methods were significantly correlated (r = +0.97, p < 0.001). Plasma PLP concentrations of 11 samples determined by the micromethod (&OV0335; = 151.8 ± 30.0 pmol/ml) were similar and significantly correlated (r = +0.95, p < 0.001) to levels measured in the same samples 1–2 years earlier (&OV0335; = 145.1 ± 26.2 pmol/ml). This suggests that plasma PLP content of the samples was stable for up to 2 years of storage when the micro-method was utilized for analysis. The strong significant correlation between macro- and micromethods attests that the micromethod is a reliable alternative to the macromethod. The micromethod is useful in instances where only small samples of plasma are available for measurement of PLP.

Cognitive performance of Egyptian adults as a function of nutritional intake and sociodemographic factors

Abstract This study was designed to investigate whether variability in adult cognitive performance was associated with variability in dietary energy intake or with variability in dietary intake quality, as defined by intake of animal source foods. In addition, we also investigated whether the impact of nutrition was amplified by covarying nonnutrient risk factors. Participants were 54 Egyptian male adults and 101 Egyptian female adults. Using a combination of oral recall and weighing of food portions, the level of individual dietary intake was established for 22 specific nutrients, including measures of energy (kilocalories), macronutrients (fat, protein), and micronutrients (vitamins, trace minerals). Adults were mildly deficient in specific trace minerals and vitamins, but were not clinically malnourished. Participants were tested on four subscales from the Egyptian version of the WAIS-R and the Ravens Progressive Matrices. In addition we also obtained measures of family SES, individual education level, and adult height as a proxy for prior nutritional status. Results indicated that male cognitive performance was primarily associated with intake of animal source foods, with a small contribution of socioeconomic status. Female cognitive performance was primarily associated with level of education, with a small contribution from animal source foods. The results emphasize the salience of nutritional intake for adult cognition, even with populations that are not clinically malnourished. The results also emphasize the importance of studying nutritional influences as part of a larger system of multiple determinants of human behavior.

Prevalence and functional correlates of obesity in an Egyptian village

The objective of this analysis was to investigate obesity and its correlates in 147 men and 286 women 15 to 74 years from the Egyptian project of the Nutrition Collaborative Research Support Program (CRSP). According to National Center for Health Statistics (NCHS, 1983) standards for body mass index (BMI), nearly twice the proportion of women (25.1 and 10.1%) were overweight or obese compared to men (12.9 and 6.8%), using body mass index (BMI). Although not for men, women reporting heart disease or diabetes had higher BMI and were older. High maternal pre‐pregnant BMI was also related to adverse pregnancy outcome, i.e., multiple births and complicated deliveries, and higher infant birthweights. Given that the likelihood of a lighter weight infant was greater for leaner women and that women regardless of their pre‐pregnancy weight had low pregnancy weight gains, one could suggest that women in this community are vulnerable to the risks of low pregnancy weight gains and that high pre‐pregnancy relative weig...

The significance of children's age in estimating the effect of maternal time use on children's well-being

The womens initiative launched by the United Nations Decade for Women has sparked unresolved controversy over the consequences of mothers increased participation in economically productive activities on childrens well-being. Clearly, in many developing countries, poor mothers face stringent time constraints requiring trade-offs in time allocated to various activities, including child caregiving. However, the impact of these trade-offs on childrens well-being remains unclear. The effect of maternal time use on childrens nutrition and health status requires more rigorous examination. In particular, the role of childrens age in this relationship is critical. Although childrens requirement for maternal care varies with factors such as their age (a proxy for stage of psychobiological and sociocultural development), season of year and family size and structure, childrens age has not been highlighted in the debate or in the relevant research. This paper documents childrens age as a critical factor in the relationship between maternal patterns of time use and the well-being of children 18-30 months of age in peri-urban Egypt. It describes differences in maternal patterns of daily time use according to childrens age and illustrates the differential associations between maternal daily activity patterns and childrens well-being by childrens age. Quantitative data collected on 161 mother-toddler pairs included information on maternal daily time allocation, childrens dietary energy intake and diarrheal morbidity, maternal hemoglobin, and household and individual sociodemographics. Data were stratified by childrens age at 24 months and were analyzed cross-sectionally using multiple linear and logistic regression. Results indicated that the age of two is critical in Kalama. At this age, toddlers begin to receive less time-intensive care freeing mothers for economic and self production. With respect to childrens well-being prior to age two, frequency of feeding was positively related to their energy intake and more time spent in household sanitation activities reduced childrens risk of diarrhea (during the diarrhea season). After two years of age, the maternal behaviors measured did not affect childrens energy intake; however, childrens diarrheal risk was reduced (during the diarrhea season) when mothers held them more and allocated more time to household sanitation year-round. We recommend that other investigators carefully examine the relationships between childrens well-being according to developmentally-defined child age intervals and maternal patterns of time use. Results will help to resolve concern over the effect of maternal participation in economically productive activities on childrens well-being.

Dependability and precision of anthropometric measures in a longitudinal field study in an Egyptian village

Reliability and its components, precision and dependability, are analyzed for a complex dataset involving longitudinal anthropometric measurements on subjects of varying ages in an Egyptian village setting. Results are compared with other published datasets. Technical error of measurement is similar to or compares favorably with other datasets for both adults and children. Overall reliability is strongly influenced by dependability coefficients, which are calculated in this analysis over relatively longer time periods (2 weeks for young children and longer for older individuals) than in other comparable datasets. It is evident that some components of the theoretical construct of imprecision, i.e., measurement error derived from variation over longer periods of time in factors contributing to accuracy, are actually captured in the analytical component of variance called undependability.