A Single-Carbon Stable Isotope Ratio Model Prediction Equation Can Estimate Self-Reported Added Sugars Intake in an Adult Population Living in Southwest Virginia

The delta C-13 value of blood is a novel proposed biomarker of added sugars (AS) intake. AS prediction equations using either a single- (delta C-13) or dual-isotope model (delta C-13 and delta N-15) were previously developed in an adult population with high AS intake living in southwest Virginia (reference group). The purpose of this investigation was to test the delta C-13 single- and delta C-13 and delta N-15 dual-isotope prediction equations for AS intake in adults with a lower mean AS intake and different demographic characteristics (test group). The blood samples for the reference (n = 257 for single-isotope, n = 115 for dual-isotope) and test groups (n = 56) were analyzed for delta C-13 and delta N-15 values using natural abundance stable isotope mass spectrometry and were compared to reported dietary AS intake. When the delta C-13 single-isotope equation was applied to the test group, predicted AS intake was not significantly different from reported AS intake (mean difference & PLUSMN; standard error = -3.6 & PLUSMN; 5.5 g, Z = -0.55, p = 0.51). When testing the dual-isotope equation, predicted AS was different from reported AS intake (mean difference & PLUSMN; SEM = 13.0 & PLUSMN; 5.4 g, Z = -2.95, p = 0.003). delta C-13 value was able to predict AS intake using a blood sample within this population subset. The single-isotope prediction equation may be an alternative method to assess AS intake and is more objective, cost-feasible, and efficient than traditional dietary assessment methods. However, more research is needed to assess this biomarker with rigorous study designs such as controlled feeding.