We have recently demonstrated successful estimation of postprandial glucose fluxes using a novel triple tracer technique after ingestion of a mixed meal containing complex carbohydrates (CC) that is naturally enriched with 13C polysaccharide ([13C]-PS). We also reported higher insulin sensitivity (SI) with CC than simple carbohydrate (SC) containing mixed meals. The current analysis was designed to determine if [13C]-PS per se could directly measure hepatic (SIH) and disposal SI (SID) during the CC containing mixed meal. Sixteen healthy subjects (9M, age=33±2 y, BMI=23±1 kg/m2) received, in random order, either SC (labeled with [13C]-glucose) or CC (naturally containing [13C]-PS) mixed meals. All meals were isocaloric and contained 50g carbohydrates with similar macronutrient composition. Plasma glucose, [13C]-glucose and insulin were measured and the Single Tracer Oral Minimal Model applied to estimate SIH and SID. The model well predicted the data. SIH was significantly higher, while SID was numerically but not statistically higher in CC than SC meals (Figure 1). This implies that the higher SI with CC meals is likely due to higher hepatic insulin sensitivity. Taken together, the data suggest that a single, naturally occurring [13C]-PS tracer can measure postprandial SI and its components without the need for the triple tracer method.
C. Dalla Man: Research Support; Self; Sanofi-Aventis Deutschland GmbH. R. Visentin: None. M. Schiavon: None. A. Basu: Consultant; Spouse/Partner; GENFIT. Research Support; Spouse/Partner; AstraZeneca. C. Cobelli: None. R. Basu: Consultant; Self; GENFIT. Research Support; Self; AstraZeneca.
National Institutes of Health (DK085516, DK94331, DK29953); Italian Minister for Education