Location: Children's Nutrition Research Center
2014 Annual Report
Objectives
There is an ongoing need to enhance our understanding of the influences and role of various nutrients on fetal, postnatal, and childhood health, growth, and development as well as the etiology of obesity. A goal of this project is to provide evidence-based nutrient bioavailability data for the development of nutritional guidelines in children 6-24 months of age by: 1) using stable isotopes to assess the absorption of calcium, zinc, and magnesium over a range of usual dietary intakes in groups of children at 6-12, 12-18, and 18-24 months of age; 2) relate mineral absorption values to dietary mineral intake and body composition as determined by DXA; 3) evaluate mineral absorption and body composition in a group of preterm infants. We plan to increase understanding of how diet and age influence gut microbial population composition and promote health; we will: 4) determine effects of diet/age on gut microbial composition and relate these to gut barrier function and inflammation in children 7-18 years of age; 5) develop de novo method to assemble short sequence reads into contigs; apply method to assemble gut microbiome sequence reads; develop statistical method to cluster contigs and quantify abundance of these clusters; perform genetic association testing for haplotype-microbiome interactions that affect risk of childhood obesity; and 6) identify panel of human mRNAs indicative of environmental enteropathy (EE); evaluate as biomarker for EE in other populations; test whether micronutrient and/or fish oil supplements can reduce EE; explore microbiome of children with and without EE; correlate mRNA panel markers with child growth parameters. Additionally we will determine: 7) negative effect of obesity-induced inflammation and oxidative stress on women's fertility and if it can be reversed by weight loss and supplemental nutrients with antioxidant and anti-inflammatory properties; 8) if pre-pregnant lipid supply underlies the insulin resistance and increased susceptibility to gestational diabetes in obese women and if exercise and modified diet will decrease the prevalence of gestational diabetes; 9) whether children born to obese and/or gestational diabetic mothers have an altered macronutrient metabolism; 10) the relationship of vascular function to insulin resistance in youth; and relationship of monocyte function and serum inflammatory markers and vascular reactivity to insulin sensitivity; 11) the effect of hyperglycemia on endothelial function, monocyte function and inflammatory markers; and 12) individual variability, metabolic pathways, and genetic variants underlying differences in obligatory and adaptive components of energy expenditure and macronutrient utilization in non-obese and obese children.
Approach
A multi-discipline approach will be undertaken to improve our understanding of how foods support health, meet dietary requirements, and reduce disease risk such as cardiovascular disease and obesity. Our studies will utilize stable isotope techniques to provide accurate, practically applicable information that may be obtained from the study populations in a safe manner. Comparison will be made of intake and absorption of calcium and magnesium with total body bone mineral as determined by Dual Energy X-ray Absorptiometry. For magnesium and zinc, comparisons will be made of estimated retained minerals with expected tissue accretion rates in early childhood. We will also evaluate these values in a group of preterm infants who may have greater nutrient requirements due to the need to have catch-up growth. For other studies, obese and normal weight infertile women will be recruited, measured, and assigned a calorie-specific diet. Numerous biological measurements will be taken and correlations between body fat and other outcomes will be made. Additionally, we will conduct a cross-sectional study to evaluate endothelial dysfunction in obese youth with and without Type 2 diabetes compared with normal weight controls with the primary aim to explore the effect of insulin resistance vs. hyperglycemia on endothelial function. A cross-sectional study design will also take place comparing non-obese/obese adolescents wherein plasma samples will be collected and DNA will be sequenced and analyzed. Furthermore we will determine the effects of diet and age on gut microbial composition, ascertain the metagenomic profile of the gut microbes, and relate these to gut barrier function and inflammation in children 7-18 years of age; and develop a new de novo assembly method to assemble short sequence reads into long contiguous reads and apply this method to assemble gut microbiome sequence reads. Development of a statistical method to cluster contigs and quantify abundance of these clusters will occur, and we will perform genetic association testing for haplotype-microbiome interactions that affect the risk of childhood obesity. Researchers will identify a panel of human mRNAs in fecal samples indicative of environmental enteropathy, evaluate this panel as a biomarker for environmental enteropathy in other populations, test whether micronutrient and/or fish oil supplements can reduce environmental enteropathy.
Progress Report
Project 1: This project only recently started and at this time we have reviewed the project plan and begun discussions with a pharmacy about the preparation of the materials needed for the study. We have also begun to develop the human use approval documents that will be submitted this fall.
Project #2. This project only recently initiated, thus staff have been recruited, operating procedures have been written, and the first subjects have been recruited for the study. For Objective 3, our study focuses on gut irritation in rural African children which is associated with poor growth and development. This work has been planned and the many human study applications have been submitted.
Accomplishments
