The Breath Carbon Isotope Ratio is a Promising Biomarker of Added Sugar Intake

Abstract

High consumption of added sugars in the US is a significant public health concern. Added sugar intake is widely misreported, hampering efforts to understand its association with health. The carbon stable isotope ratio has been proposed as a biomarker of added sugar intake, because it is elevated in corn and sugar cane, the source of most added sugars consumed in the US. The objective of this study was to investigate the carbon isotope ratio of breath as a biomarker of short term (same day) added sugar consumption. Breath can be collected quickly and non‐invasively, and breath carbon isotope ratios can be rapidly measured using cavity ring‐down spectroscopy (CRDS). If shown to be a valid measure of short term added sugar intake, the breath carbon isotope ratio could be feasibly collected and measured multiple times, then averaged to estimate usual intake. Our objective was to test whether breath carbon isotope ratios could distinguish low (0 g/day), medium (75 g/day) and high (150 g/day) added sugar intakes, using a randomized cross‐over study of 12 adults (6 female, 6 male). Diets were 50% carbohydrate, 30% fat, and 20% protein, and included breakfast and lunch only (delivering 60% of daily energy and added sugar target values). On each study day, participants provided breath samples by blowing into a gas sampling bag at 8 am (fasted), 10 am, 12 pm, 2 pm and 4 pm, and were served breakfast and lunch following the 8 am and 12 pm sampling times, respectively. There were 1–2 weeks between each treatment day. The effect of added sugar level on breath carbon isotope ratios was analyzed for each sampling time point using Analysis of Covariance, including sex, age, and fasting breath isotope ratios as covariates. Breath carbon isotope ratios increased significantly with added sugar intake, and differed significantly between all three treatments (low, medium and high added sugar, all P < 0.0001) at all four post‐feeding time points (10 am, 12 pm, 2 pm and 4 pm). Fasting breath carbon isotope ratios were a significant covariate, especially for the 10 am and 12 pm measurements. This preliminary work shows that breath carbon isotope ratios are promising measures of short term sugar intake that are non‐invasive and easily‐collected. If collected over multiple days and averaged, these measures could potentially provide objective biomarkers of usual added sugar intake for epidemiological research.Support or Funding InformationP30 GM 103325‐03