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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Research Project #436283

Research Project: Intestinal Microbiome and Childhood Feeding

Location: Children's Nutrition Research Center

2021 Annual Report

Objective 1: Compare the effects of inulin and fructo-oligosaccharides against a maltodextrin placebo in obese children, using a double-blind randomized controlled trial, to study weight loss, fecal microbiota and their functions. Objective 2: Among children from low-to-middle income countries with severe acute malnutrition (SAM) to: a) longitudinally characterize epigenomic, and metabolomic responses to SAM treatment; b) assess amino acid content of hair samples taken before, during, and after therapy to identify biochemical markers of nutritional status and therapeutic response, and; c) investigate the role of a newly identified hormone – Asprosin – in the recovery of satiety during SAM refeeding therapy by integrating serial measurements in plasma with clinical nutritional data on caloric intake and weight recovery. Objective 3: Conduct a clinical trial adding black-eyed peas to diets of young children at risk for stunting. Determine efficacy in reducing stunting and analyze fecal sample to understand potential mechanisms by which the food supplement ameliorates stunting. Assess dietary compliance in a novel, quantitative manner using a urinary biomarker for black eyed peas. Currently quercetin and ferulic acid are candidates for this biomarker.

A number of pressing nutritional issues face the US and other nations. Over 20% of children throughout the world are obese with even more children overweight; both associated with diabetes and heart disease. Given the importance of the gut bacteria in our general health and weight control, we will test via various sample analyses a dietary supplement (prebiotic) that selectively enhances the growth and activity of bacteria associated with leanness. We anticipate that this prebiotic will reduce the risk of overweight and obesity in children. At the opposite end of the nutritional spectrum, severe acute malnutrition directly contributes to deaths of more than a million children under 5 yrs. old each year globally. There is a lack of molecular and metabolic biomarkers of existing nutritional therapy limiting the ability to appropriately and adequately assess the utility of dietary supplementation. We will perform serial measures of DNA methylation and tissue metabolites to identify suitable biomarkers of nutritional deficit and recovery. In addition, stunting affects about 23% of all children under 5 years of age globally. Most of these children are in Africa and south Asia and the consequences include lower economic productivity, decreased cognition and more diabetes and hypertension. Similar to obesity, the microbiome is implicated as a cause of stunting and new treatments are needed. We will determine using biomarker analysis if legume supplements can extend their benefits to children in West Africa.

Progress Report
Our overall research objective is to compare the effects of inulin and fructo-oligosaccharides (prebiotics) against a maltodextrin placebo in obese children, using a double-blind randomized controlled trial to study weight loss, fecal microbiota and their functions. Due to restrictions related to the COVID-19 pandemic, we have not been able to start enrolling participants into the study. We were able to set up the assays that will measure whether the activity of the immune system in the intestines is increased. These assays will aid in telling us how prebiotics exert their beneficial effects on the gut and help to reduce weight gain in children. For Objective 3, nations around the world have interrupted clinical research activities due to the pandemic, including Ghana and Mali where the legume trial for Objective 3 was originally planned. Evidence is emerging that carbohydrate content of the diet is a major determinant of gut health as it acts through the gut microbiome and its associated metabolome. Sub-objective 3A has been modified to now focus on milk versus black-eyed peas and its primary carbohydrate (lactose) and protein and the potentially beneficial effects that will provide new knowledge that will guide food usage. The new study associated with Sub-objective 3A titled "Milk Matters" is a prospective, double-blinded, randomized, controlled clinical effectiveness trial. We will compare ready-to-use supplementary foods (RUSFs) of differing carbohydrate and protein compositions in the treatment of moderate acute malnutrition (MAM) and its effects on gut permeability and intestinal microbiome with the goal of developing sustainable nutritional interventions to decrease poverty and hunger. The aim of this study is to test the effectiveness of lactose separate from dairy protein and in combination with dairy protein compared to vegetable proteins and carbohydrates on recovery of MAM in Sierra Leone, Africa. The secondary aim, which will be conducted in a sub-set of participants includes changes in intestinal permeability as measured by the percent of lactulose excretion in the lactulose absorption test at the completion of the feeding, fecal microbiome configuration changes at the completion of the trial, the fecal metabolome, and rates of growth. In this study 900 children between the ages of 6-59 months presenting with MAM at one of the sites in Pujehun, Sierra Leone, will be enrolled in the study and randomized to one of four RUSFs each with differing milk protein/carbohydrate and vegetable protein/carbohydrate combinations. This study is well underway with over 50% of the participants enrolled in both the main and sub-study. Sub-objective 3B has made great progress. The project geared towards this Sub-objective, 'Measuring Cowpea (Black-eyed peas) Consumption', developed a method using urinary metabolites unique to cowpea to identify dietary exposure and quantify levels of dietary intake for children and adults. The goal of this project was to identify a novel set of dietary biomarkers that would measure black-eyed pea consumption, free from participant recall bias, and serve to quantify legume intake. The varieties in use in Ghana were first explored, then a supervised feeding exercise was conducted in northern Ghana among 20 adults and 20 children. For 5-day periods the subjects consumed a fixed about of cowpea ranging from none to large amounts. Urine and blood samples were collected and analyzed using untargeted metabolomics to discern patterns of phytochemicals indicative of black-eyed pea consumption in a quantitative manner. Because pigeon pea consumption is inseparably associated with cowpea consumption, this study afforded us the opportunity to consider biomarkers for this food as well. The deliverable from this project is a urinary biomarker for black-eyed pea consumption utilizing 2-hexenoylcarnitine, ginkgoic acid and UNPD175583. Precision nutrition with future efforts to capture the multiple dynamic of the human diet with a reliable measurement for dietary intake is possible. This precision data would reduce the time and inconsistency associated with the current dietary recall. Through this project we were able to identify 10 candidate biomarkers for black-eyed pea consumption which include phytochemicals unique to plants and other biomarkers that tell us what the effect of black-eyed pea in human metabolism and provides insight into how black-eyed peas strengthen human nutrition. In addition, 4 variety-specific biomarkers were identified. Variety biomarkers could prove to be an important tool if a specific variety is shown to be more nutritious or provide a benefit.

1. Measurement of B-defensin-2 in stool. The human intestine is comprised of trillions of bacteria, and this massive collection of bacteria can affect the function of the immune system since the largest collection of immune cells is also in the intestines. Any treatment that affects the bacteria in the intestines, such as probiotics or a significant diet change, can alter the types of bacteria in the gut and hence the immune system can be affected. Therefore, researchers need to have a test that could tell us whether the activity of the immune system in the intestine is increased. Researchers in Houston, Texas, developed a test that measures a specific protein called B-defensin-2, which is an important part of the immune system in the gut. This analysis can detect changes in the activation of the immune system in children with different types of intestinal disorders. This information will help determine how different nutrients affect the function of the immune system in the gut which impacts the individual's overall health.