Evaluation of a novel biomarker of added sugar intake (δ13C) compared with self-reported added sugar intake and the Healthy Eating Index-2010 in a community-based, rural US sample

Objective: The delta C-13 value of human blood is an emerging novel biomarker of added sugar (AS) intake for adults. However, no free-living, community-based assessments of comparative validity of this biomarker have been conducted. The purpose of the present investigation was to determine if Healthy Eating Index-2010 (HEI-2010) score, SoFAAS score (HEI-2010 sub-component for solid fat, alcohol and AS), AS and sugar-sweetened beverage (SSB) intakes were associated with delta C-13 value of fingerstick blood in a community-based sample of adults, while controlling for relevant demographics. Design: A cross-sectional analysis of data obtained from assessments of BMI, dietary intake using 24 h recalls and a fingerstick blood sample was completed. Statistical analyses included descriptive statistics, multiple linear regression and one-way ANOVA. Setting: Rural Southwest Virginia, USA. Subjects: Adults (n 216) aged > 18 years who consumed at least 837 kJ/d (200 kcal/d) from SSB. Results: This sample of adult participants with low socio-economic status demonstrated a mean HEI-2010 score of 43.4 (SD 12.2), mean SoFAAS score of 10.2 (SD 5.7), mean AS intake of 93 (SD 65) g/d and mean blood delta C-13 value of -18.88 (SD 0.7) %. In four separate regression models, HEI-2010 (R-2= 0.16), SoFAAS (R-2= 0.19), AS (R-2 = 0.15) and SSB (R-2 = 0.14) predicted delta C-13 value (all P <= 0.001). Age was also predictive of delta C-13 value, but not sex or race. Conclusions: These findings suggest that fingerstick delta C-13 value has the potential to be a minimally invasive method for assessing AS and SSB intake and overall dietary quality in community-based settings. Strengths, limitations and future areas of research for using an objective delta C-13 biomarker in diet-related public health studies are discussed.