BACKGROUND: Previous studies have reported that the type of protein consumed as preloads significantly affects postprandial glucose and insulin excursions in healthy and type 2 diabetes. But little is known how protein synergistic preloading affects human health.
OBJECTIVE: Using two typical Asian protein type (soya tofu and chicken) with carbohydrate (white rice), the aim of this study was to compare the effects of two different protein types presented synergistically as preloads on postprandial glycemia, insulinemia and incretin secretions in healthy adults.
DESIGN: Sixteen healthy Chinese male adults participated in a randomized, controlled, crossover meal trial. Subjects consumed, in random order, 4 experimental meals that differed in protein type and proportion. Glucose, insulin, incretins and triglyceride concentrations were measured over 3 h.
RESULTS: There were significant protein type preload treatment x time interaction effects on plasma glucose, insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and triglycerides concentrations (P < 0.001). In comparison with rice alone treatment, preloading with Soya, Chicken and Soya/Chicken (50% soya tofu combined with 50% chicken breast) prior to rice consumption all significantly attenuated postprandial glucose response. Soya + Rice treatment induced a significantly lower incremental peak and incremental area under curve (iAUC) (0-60 min) glucose level compared with Chicken + Rice. The postprandial insulin response (incremental peak, iAUC 0-180 min) was significantly lower after Soya + Rice than Chicken + Rice group. Soya/Chicken + Rice treatment did not induce any significant difference in glucose and insulin levels between Soya + Rice or Chicken + Rice group. Notably, Soya/Chicken + Rice as well as Soya + Rice induced a significantly higher GLP1 and GIP responses compared with Rice or Chicken + Rice groups. Soya + Rice and Soya/Chicken + Rice groups stimulated higher triglyceride concentration than the other two groups.
CONCLUSIONS: Different protein preload with rice can considerably influence its glycemic, insulinemic and incretin responses. Soya or Soya/Chicken protein synergistic preloading induced higher incretins responses to modulate glycemic response in healthy adults.
