The addition of mycoprotein to a mixed-meal impacts postprandial glucose kinetics without altering blood glucose concentrations: a randomised controlled trial

Background: Mycoprotein is a high-fibre food previously shown to reduce postprandial glucose concentrations when ingested within a mixed-meal. We applied a dual stable isotope tracer approach to determine whether this is due to a reduced rate of appearance of glucose, in participants of ranging BMI. Methods: Twenty-four adults (F = 8, BMI 30 ± 6 kg·m⁻²) attended 2 trials in a double-blind, randomised, cross-over design. Participants ingested two energy and macronutrient matched milk-based drinks (enriched with 1000 mg [U-¹³C₆] glucose in a subset of 12 participants), containing 50 g glucose and either 0 (CON) or 20 g (MYC) mycoprotein. A primed continuous intravenous infusion of D-[6,6-²H₂] glucose determined plasma glucose kinetics over 6 h. Postprandial time-course, and AUC, of glucose and insulin concentration, rate of disappearance (RdT) and appearance of exogenous (RaEx), endogenous (EGP), and total (RaT) plasma glucose were assessed using two- and one-way ANOVA. Results: Drink ingestion increased blood glucose and serum insulin concentrations (P < 0.05) and were comparable between conditions (P > 0.05). Both RaT and RdT were higher with MYC compared with CON over 6 h (mean 6 h glucose appearance and disappearance increased by 5 and 9%, respectively, P < 0.05). RaEx was not affected by MYC ingestion over 6 h (P > 0.05). The mean contribution of EGP to total glucose appearance was 15% greater with MYC, with a trend towards significance (P = 0.05). There was no relationship between BMI and the response to MYC ingestion for any of the variables (P < 0.05). Conclusion: The ingestion of mycoprotein within a mixed-meal impacted postprandial glucose kinetics, but not blood glucose or serum insulin concentrations, in individuals of ranging BMI. Clinical trial registry number and website: This trial was registered at clinicaltrials.gov as NCT04084639 and can be accessed at https://clinicaltrials.gov/ct2/show/NCT04084639.