Biomarker Assessment of Adherence and Effectiveness in a Randomized Controlled Trial to Reduce Added Sugar Intake in Adolescents - PROJECT ABSTRACT Added sugar (AS) is a critically important dietary target for intervention in adolescents; it contains excess calories with no nutritional value and is independently associated with chronic disease risk. Adolescents consume more AS than any other age group and are at a unique phase in the life course where improving diet could have a significant influence on overall health into adulthood. However, capturing dietary change remains a paramount challenge in the field of nutrition and this is particularly true for overconsumed nutrients like AS that are highly susceptible to reporting error and social desirability bias. The challenge of dietary self-report is also pronounced in behavioral trials where issues like participant burden, repeated measures, and small sample sizes have significant impacts on the ability to accurately assess outcomes. The carbon stable isotope ratio (CIR) is a low-burden and valid measure of AS and sugar-sweetened beverage (SSB) intake that warrants additional investigation in dietary interventions. Most of the evidence on CIR to date is derived from controlled feeding studies and observational trials using blood and hair CIR. Breath CIR has recently been validated as a measure of short and long-term AS intake and provides an exciting new avenue to explore AS intervention adherence and effectiveness in behavioral trials. Thus, the purpose of this R03 is to examine CIR from breath as an indicator of intervention adherence (i.e., short-term intake) and intervention effectiveness (i.e., change over time). Additionally, this study aims to assess the differential feasibility, acceptability, and sensitivity to change among CIR from breath, blood, and hair samples to inform work in future trials. This R03 study will be mapped onto a randomized controlled trial (RCT) in an ongoing K01 study. Adolescents (n=70) 12-16 years will be randomized to a 12-week behavioral intervention to reduce AS intake (n=35), or a nutritional education comparison (n=35). This R03 study will 1) Assess the feasibility and efficacy of using daily breath CIR (fasting morning, postprandial afternoon, and evening) to capture intervention adherence via repeated sampling over 12-weeks (at baseline, and in weeks 3, 6, 9, and 12); 2) Examine AS intervention effectiveness based on changes in breath CIR from baseline to end-of-intervention (12-weeks) between intervention and control participants; and 3) Compare feasibility, acceptability, and sensitivity to change of breath, blood, and hair CIR to capture change in AS over 12 weeks. This R03 will enhance the impact of the PI's existing K01 by adding innovative breath CIR measures and analyses, which will provide robust evidence for objectively assessing AS intervention adherence and effectiveness. Additionally, this study will test assessment approaches that could reduce participant burden and eliminate reliance on dietary self-report, resulting in more efficacious strategies for populations at greatest risk of diet-related health disparities. Findings will facilitate the PI's research trajectory to advance the science of dietary assessment methodology and expand the evidence for the use of objective biomarkers in behavioral nutrition interventions.
