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 δ13C AS intake biomarker values.

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 δ13C 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.

Rural Southwest Virginia, USA.

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 %).

A significant group by time difference in δ13C value was detected (P<0·001), with mean (sd) δ13C 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 δ13C values were consistent with changes in self-reported AS and SSB intakes.

The δ13C 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.

The δ 13C 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 δ 13C value of fingerstick blood in a community-based sample of adults, while controlling for relevant demographics.

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.

Rural Southwest Virginia, USA.

Adults (n 216) aged >18 years who consumed at least 837 kJ/d (200 kcal/d) from SSB.

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 δ 13C 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 δ 13C value (all P≤0·001). Age was also predictive of δ 13C value, but not sex or race.

These findings suggest that fingerstick δ 13C 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 δ 13C biomarker in diet-related public health studies are discussed.