Response of the Gut Microbiome and Circulating Metabolome to Diet in Children: Ancillary Study to KIDFIT (NCT03405246)

This is an ancillary study to KIDFIT (NCT03405246). KIDFIT tests whether preschool-age children, born to overweight or obese mothers, respond to a healthy DASH diet intervention with better cardiovascular health. This ancillary study to KIDFIT investigates how the children's gut microbiomes (bacteria in the intestines) and blood metabolomes (small molecules in the blood) are affected by the DASH diet intervention, and how the microbiome and metabolome relate to the children's cardiovascular health over time. The investigators hypothesize that (1) the DASH diet will modify the gut microbiome and blood metabolome, (2) the gut microbiome and blood metabolome will be related to each other, and (3) the microbiome and metabolome will be associated with the children's cardiovascular health profiles (things like weight, body fat, blood pressure, and cholesterol).

The majority of deaths from cardiovascular disease (CVD) in US adults ages 25-54 years are associated with suboptimal diet. While diet is an important target of CVD prevention efforts in adults, intervention on the childhood diet may be more effective. Animal data suggest that early-life diet has the unique potential to modulate biological systems and durably program a child's biology for long-term health or disease. The objective of this study is to define the molecular effects of a dietary pattern intervention on the gut microbiome and circulating metabolome in young children. This objective will be attained through an ancillary study to KIDFIT, a clinical trial that tests the effects of a 12-month Dietary Approaches to Stop Hypertension (DASH) diet intervention on adiposity and other cardiovascular health (CVH) metrics (e.g., blood pressure, lipids) in 3- to 5-year old children. Using additional participant samples, deep phenotyping and advanced bioinformatics, the ancillary study will address three specific aims. First, it will test the effect of the DASH diet intervention on the gut microbiome, including abundances of microbial taxa, communities, and metabolism-related genes and transcripts. Second, it will define the associations of diet and the gut microbiome with the circulating metabolome. Using targeted and nontargeted metabolomics approaches, blood metabolites, metabolite networks, and metabolic pathways will be evaluated. Finally, in an exploratory fashion, it will probe pathways linking the diet intervention with subsequent adiposity and CVH metrics, through the gut microbiome and serum metabolome. The expected outcome is a preliminary model of how the DASH diet alters the gut microbiome and circulating metabolome in young children, and how these alterations relate to short-term CVH outcomes.