Effect of Soluble Corn Fiber supplementation for 1 year on bone metabolism in adolescents (MetA-Bone Trial)

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Project Summary This Administrative Supplement for Research on Dietary Supplements is for year 5 of the funded parent grant “MetA-Bone Trial” (# 5R01HD098589-04), a randomized double-blinded placebo- controlled trial to determine the effects of 1-year soluble corn fiber (SCF) supplementation on bone metabolism in children. This proposal will expand our research on the effects of SCF (a prebiotic fiber) on the gut microbiome diversity and how this is associated with changes in body composition inflammatory biomarkers in this sample. A total of 110 participants have been recruited so far, of which >75% are minority (68% are Hispanics and 8% are Blacks). Fecal, 24-h urine, and blood samples are being collected and saved in our biorepository for future analysis. Evidence shows that the gut microbiome is associated with obesity, which is particularly higher among Hispanics and Blacks. Obesity has been associated with a different bacteria composition (less bacterial diversity and reduced Bacteroidetes/Firmicutes ratio). Diets low in fiber (which is very common in US children) also changes the microbiota. These changes in the gut could lead to chronic, low-grade inflammation. This could be reversed or improved by prebiotic fiber supplementation. The only 2 studies to date supplementing children with inulin (another type of prebiotic fiber) found significant decreases in body weight z-score, percent body fat, IL-6, and gut microbiome composition. However, to our knowledge, there are no studies evaluating the effects of SCF on gut microbiome diversity, body composition, and in inflammatory biomarkers in children or in minorities. The aims of this administrative supplement are: (1) Evaluate the changes in the gut microbiome diversity (through Shannon, Simpson, and Inverse Simpson indices, measures of richness and evenness; new analyses) with 1-year SCF supplementation and how this is associated with changes in body composition (% fat mass and lean mass from DXA scan); (2) Evaluate the changes in inflammatory biomarkers (fecal calproctectin, urinary IL-6, and serum CRP; new analyses) with 1-year SCF supplementation and if these changes are mediated by changes in body composition; and (3) Engage 2 graduate students in training and mentorship to build future research capacity for studying the role of dietary supplements in health and disease prevention. If successful, the results from this application will improve our understanding of the role of SCF on gut microbiome, body composition, and inflammation. This could lead to designing interventions to promote supplementing diets with SCF for improving health and potentially preventing chronic conditions associated with excessive fat mass and low-grade inflammation in minority children and adolescents.