Charles Yarbrough

Relations between nutrition and cognition in rural Guatemala.

The nutritional status of three and four year old children, as measured by height and head circumference, is related to cognitive performance in four rural Guatemalan villages. The relationships persist when social factors are taken into account. Families in two of the villages participate in a voluntary, high protein-calorie supplementation program. In the other two villages, the families receive a vitamin and mineral supplement with one-third of the calories. Although the longitudinal study still is ongoing there is some evidence that the children who receive the higher calorie supplement (or whose mothers received it during pregnancy and lactation) are most likely to score high in cognitive performance. The results support other animal and human studies that report an association between nutrition and cognitive development. The findings, while not diminishing social environmental explantions of differences in cognitive function, suggest the worth of nutrition intervention programs in rural areas of lesser-developed countries.

Effect of moderate maternal malnutrition on the placenta.

The results of two studies of the influence of moderate maternal malnutrition on the weight and chemical characteristics of the placenta are discussed. In the first study, two groups of pregnant women of high and low socioeconomic status from Guatemala City were studied. Socioeconomic status was defined by family income, educational level of the mother, and environmental sanitary conditions. Both groups were very similar with respect to age, parity, gestational age, and absence of severe disease during pregnancy. The average placental weight in the low socioeconomic group was 15 per cent below that of the high socioeconomic group and there was a consistent association between the postpartum maternal weight and placental weight. There were no differences between the two groups regarding placental concentration of fat, protein, water, ash, hemoglobin, and DNA; hydroxyproline and fat concentration were significantly lower in the low socioeconomic group. The hypothesis that the difference in placental weight observed between the two groups was primarily due to maternal nutritional status was tested in the second study by means of nutritional intervention in four rural villages in Guatemala. Two of the villages received a protein-calorie preparation while the other two received a calorie supplement. Placental weight was higher among women with high levels of supplemented calories during pregnancy, independently of the type of food supplement ingested. On the average, the groups with low caloric supplementation (smaller than 20,000 calories) had placental weight 11 per cent below those with high caloric supplementation (larger than or equal to 20,000 calories), In contrast to placental weight, the concentration of placental chemical components studied was not associated with caloric supplementation. It was concluded that moderate protein-calorie malnutrition during pregnancy leads to lower placental weight without significantly changing the concentration of the biochemical components studied. The reduction of placental weight may be the mechanism by which maternal malnutrition is associated with high prevalence of low-birth-weight babies in these populations.

Anthropometric Field Methods: Criteria for Selection

Since “nutrition” cannot be measured directly, one must rely on measurements of indicators of nutritional status for inferential statements. One such statement addresses the issue of whether or not the nutrition of an individual has changed. This involves examining changes in the measurements of an indicator of nutritional status. In this context the indicator is dealt with as a continuous variable and as such it may also be used to identify differences in nutrition between individuals or groups of individuals. For such purposes one needs answers to the following questions: Does the indicator identify changes or differences in nutrition? Can the sensitivity of the indicator be improved? These concerns are addressed in Sections 2–7.

Genetic-environmental interactions in physical growth.

Abstract. Variability in stature among young children is often ascribed to health and nutrition differences in malnourished populations and to genetic differences in well‐nourished populations. Hence, it was hypothesized that parent‐child correlations in malnourished Guatemalan populations would be markedly lower than those reported for European samples. Instead, it was found that parent‐child and sibling correlations were similar in both kinds of populations. The simplest interpretation of these results is that variability in stature among malnourished children is as much a reflection of genetic differences as in developed nations. However, explanations can also be advanced which would attribute the higher than expected correlations to the environment. For instance, it could be that socioeconomic and nutritional status is correlated across generations. In other words, parents who had relatively better conditions as children are more likely to provide a better environment for their children. Consequently, the relative contribution of genetics and environment to variability in height is still unsettled. Nonetheless, it appears that variability in body size in malnourished populations, regardless of the relative importance of its causes, is a useful indicator of health and nutrition.

A simple assessment of the risk of low birth weight to select women for nutritional intervention

There is growing evidence that the high prevalence of low-birth-weight (LBW) babies, a characteristic of many poor societies, can be significantly reduced through nutritional intervention programs. In order to increase the efficiency of these programs, pregnant women at risk of delivering LBW babies must be identified. Several risk scales have been extensively used in urban populations of developed countries. However, these indicators are of little use in poor communities, since most of them require expensive laboratory techniques, a long interview, at least two visits to a health center, and a precise estimation of gestational age. The present paper proposes several risk indicators of LBW, appropriate for use in areas with inadequate health resources. In a four-year longitudinal study of pregnant women from poor rural villages in Guatemala, mothers of LBW babies were found to be typically small in stature and head circumference. In addition, their houses tended to be of relatively poor quality. The proportion of LBW babies found among women at risk, as defined by these indicators, was significantly lower among women with similar characteristics receiving adequate food supplementation during pregnancy. Categories of high risk were based on maternal height, head circumference, and house quality. It is concluded that use of these categories will increase the efficiency of these programs without decreasing significantly their effectiveness.

Effect of Maternal Nutrition on Infant Mortality

High infant mortality is a major health problem in many countries of the world. In these countries the infant mortality rate (IMR) remains a major determinant of life expectancy at birth and the first year of life is the single most important risk period that a person has to face. Maternal malnutrition has been implicated as an important cause of the high IMR reported in many developing nations. The objective of this paper is to review the published data on the relationship between maternal nutrition and infant mortality.

Nutrition and birth interval components: the Guatemalan experiences.

A birth interval is defined as the period between one live birth and the next (1), Beginning with a live birth, it can be divided into several components: the period of postpartum amenorrhea, the menstruating interval, and the next period of gestation (2, 3). Lactation, initiation of menstruation and ovulation after delivery, conception and intrauterine development of the fetus each place a large demand on the nutritional status of women; thus, malnutrition may lower the biological capacity to conceive, bear, and deliver a live child (4).

The Energy Cost of Diarrheal Diseases and Other Common Illnesses in Children

Diarrheal diseases and other common illnesses in children affect nutritional status by reducing appetite and by interfering with nutrient absorption and utilization.

Nutrition and Mental Development in Children

Over the past two decades a number of investigators have addressed the question of whether childhood malnutrition causes retardation in mental development. To date, an unequivocal answer has not been forthcoming. This is understandable because of the many problems involved in designing an appropriate study to demonstrate causality.

Plasma volume prediction in normal pregnancy

A predictive formula for plasma volume in the second half of normal human pregnancy has been developed using computerized linear regression techniques. The use of this and similar data analysis techniques by biologist and mathematicians working in collaboration is encouraged.