Breath ¹³CO₂—evidence for a noninvasive biomarker to measure added refined sugar uptake

Increased consumption of added sucrose and high-fructose corn syrup in the human diet has been associated with increasing incidence of obesity and metabolic disease. There are currently no reliable, objective biomarkers for added sugar intake that could be used in individuals or population settings. ¹³C is a stable isotope of carbon, and measurement of blood ¹³C content has been proposed as a marker of added sugar consumption. This study aimed to determine if breath ¹³CO₂ could represent an alternative, noninvasive biomarker to monitor added sugar intake. We undertook retrospective analyses of eight preclinical and human ¹³C-breath studies to define baseline breath ¹³CO₂ characteristics. All samples were analyzed using isotope ratio mass spectrometry, and breath ¹³CO₂ was expressed as the delta value, d expressed as parts per thousand (%). All data are expressed as mean ± SEM, with statistical significance considered at P < 0.05. Breath d¹³CO₂ was significantly elevated in a cumulative manner in rats and mice that consumed a diet containing at least 15% sucrose. Mice fed an American rodent chow diet containing 50% sucrose and 15% corn starch had a significantly higher breath d¹³CO₂ compared with rodents consuming an Australian rodent chow diet. Furthermore, breath d¹³CO₂ was significantly increased in a dose-dependent manner in humans that ingested a bolus dose of sucrose. These findings suggest application for baseline breath d¹³CO₂ as a noninvasive biomarker for added sugar consumption, with broad application for longitudinal assessment of population sugar intake and obesity management strategies. NEW & NOTEWORTHY We have found that breath ¹³CO₂ is increased in rats and mice consuming diets high in sucrose. We also found that human breath ¹³CO₂ is increased in humans consuming increasing amounts of sucrose. Our collective findings suggest that breath ¹³CO₂ represents a potential marker of added dietary sugar consumption.