Location: Children's Nutrition Research Center2010 Annual Report
1a. Objectives (from AD-416)
There is an ongoing need to enhance our understanding of the role of various nutrients on fetal, postnatal, and childhood growth and development. This is becoming increasingly important as studies continue to show an association between the patterns of growth during these early time periods and health later in life. At present, little is known about the functional need for different amino acids in support of these changes, and the variability in normal growth. The research objectives include: 1) define the normal range of biological diversity in body composition during specific periods of human growth; 2) define the nutritional and functional requirements of methionine, cysteine, and arginine for healthy children; 3) investigate the impact of docosahexaenoic acid (DHA) intake from food and supplemental sources on blood levels, cognitive performance, and neurophysiological function, heart rate and blood pressure, as well as a lower incidence of allergies and upper respiratory infection in children; 4) investigate the pathways and nutritional modulation of methyl group production in underweight and normal weight pregnant women; and 5) investigate differences in bowel flora, antioxidant capacity, and mitochondrial integrity between severely malnourished and well-nourished children. This project will provide novel and new information directly useful to nutritional scientists, pediatricians, industry, and governmental agencies responsible for establishing pediatric dietary guidelines. These data will have global application and provide a strong basis for evidence-based development of nutritional recommendations for children and pregnant mothers.
1b. Approach (from AD-416)
The goal of our research is to obtain better data on amino acid nutritional and functional requirements for growth and to develop reference standards for body composition during different phases of growth that can be used in the development of nutritional guidelines. Our researchers aim to determine if an intake of methionine and cysteine is more efficient to support glutathione synthesis rates in healthy children, than an equimolar intake of methionine alone. We will evaluate whether arginine supplementation in obese children improves insulin sensitivity and protein synthesis, and explore gluconeogenesis under these conditions. We will investigate the impact of docosahexaenoic acid (DHA) intake from food and supplemental sources on blood levels, cognitive performance, and neurophysiological function of 4- to 12-year-old children. We will establish reference standards for healthy growth in terms of changes in the body's muscle, protein, bone, and fat content.
3. Progress Report
Project 1. More than 1800 infants, children, and adolescents, equally representing three major ethnic groups (European-, African-, and Hispanic-Americans) have been enrolled for study on body composition. LMS modeling was used to establish first set of reference curves for changes in body composition during growth. This is the first attempt at this level of advanced modeling for the development of compositional growth curves and will allow examination of associations between chronic diseases in adulthood and infant weight at birth and the patterns of rapid weight gain during the first year of life. Project 2. We recruited and studied 24 subjects to determine methionine kinetics and transmethylation rates during the first trimester in groups of underweight pregnant women with either normal or low plasma vitamin B12 concentration and during the third trimester in the deficient group, after dietary supplementation with vitamin B12. We began collaboration with the Tropical Metabolism Research Unit, University of the West Indies. We began pilot project to test 1 million genetic markers in 60 children with kwashiorkor and 60 children who developed marasmus after extreme starvation. Study on twins and triplets in southern Malawi is part of a longitudinal study to explore the relationship between the intestinal microbiome and childhood growth and nutritional status. Our research protocol on the impact study of DHA intake from food and supplemental sources on blood levels, cognitive performance, and neurophysiological function of children has been approved by the IRB, but start of the project has been delayed awaiting delivery of the DHA supplement.
1. Unmasking vitamin B12's role in methyl production in pregnant women. Several studies have reported that pregnant women with low levels of vitamin B12 have a higher risk of delivering smaller babies. Vitamin B12 is important for methyl production for DNA and protein synthesis, which are necessary for cell division and growth of the fetus during pregnancy. To determine if women with low vitamin B12 levels may be making smaller babies due to a lack of methyl production, Children's Nutrition Research Center researchers studied methionine metabolism. We found that pregnant women with low vitamin B12 concentrations were producing methyl at the same rate as women with normal vitamin B12 levels. These results indicate that an inability to make methyl does not appear to be the reason why they give birth to smaller babies and further research is necessary to see what are the potential causes.
2. Pediatric body compositional reference curves. Until now, only hypothetical models could be used to estimate the average pattern of childhood growth. In Houston, Texas, Children's Nutrition Research Center researchers have used advanced measurement techniques to successfully assess, longitudinally, the normal variations in changes in bone and muscle mass, body water, and body fat, and its distribution from birth through adolescence for white, black, and Hispanic children. This information will impact the establishment of minimum nutritional requirements in support of healthy growth at different ages, and help better define the origins of childhood obesity.Dwarkanath, P., Kurpad, A.V., Muthayya, S., Thomas, T., Mhaskar, A., Mhaskar, R., Thomas, A., Vaz, M., Jahoor, F. 2009. Glucose kinetics and pregnancy outcome in Indian women with low and normal body mass indices. European Journal of Clinical Nutrition. 63:1327-1334.