Influence of an intervention targeting a reduction in sugary beverage intake on the δ13C sugar intake biomarker in a predominantly obese, health-disparate sample

Objective: Controversy exists surrounding the health effects of added sugar (AS) and sugar-sweetened beverage (SSB) intakes, primarily due to a reliance on self-reported dietary intake. The purpose of the current investigation was to determine if a 6-month intervention targeting reduced SSB intake would impact delta C-13 AS intake biomarker values. Design: A randomized controlled intervention trial. At baseline and at 6 months, participants underwent assessments of anthropometrics and dietary intake. Fasting fingerstick blood samples were obtained and analysed for delta C-13 value using natural abundance stable isotope MS. Statistical analysis included descriptive statistics, correlational analyses and multilevel mixed-effects linear regression analysis using an intention-to-treat approach. Setting: Rural Southwest Virginia, USA. Subjects: Adults aged >= 18 years who consumed >= 200 kcal SSB/d (>= 837 kJ/d) were randomly assigned to either the intervention (n 155) or a matched-contact group (n 146). Participants (mean age 42.1 (SD 13.4) years) were primarily female and overweight (21.5%) or obese (57.0 %). Results: A significant group by time difference in delta C-13 value was detected (P<0.001), with mean (SD) delta C-13 value decreasing in the intervention group (pre: -18.92 (0.65) %, post: -18.97 (0.65) %) and no change in the comparison group (pre: -18.94 (0.72) %, post: -18.92 (0.73) %). Significant group differences in weight and BMI change were also detected. Changes in biomarker delta C-13 values were consistent with changes in self-reported AS and SSB intakes. Conclusions: The delta C-13 sugar intake biomarker assessed using fingerstick blood samples shows promise as an objective indicator of AS and SSB intakes which could be feasibly included in community-based research trials.