Whole-food protein sources differentially modulate postprandial plasma dileucine concentration and muscle protein synthesis in humans

Details

Supervisors

Francaux, Marc ; Warnier, Geoffrey

Faculty

Faculté des sciences de la motricité

Degree label

Master [120] en sciences de la motricité, orientation éducation physique, à finalité approfondie

Abstract

enDileucine, a leucine-containing dipeptide, may enhance anabolic signaling more than leucine alone. This study examined postprandial plasma dileucine and leucine concentrations after ingesting animal- and plant- whole foods and their association with muscle protein synthesis rates (MPS) in humans. Secondary analysis was performed on plasma samples collected from two randomized controlled trials totaling 26 healthy adults (25 ± 4.3 y). Participants consumed low-fat pork (LFP), high-fat ground pork (HFP), complementary rice and beans (COMP), an iso-nitrogenous mixed nutrient beverage (ISO), or a carbohydrate control (CHO). Plasma concentrations and MPS was measured. Plasma dileucine increased significantly only after LFP ingestion (P < 0.05). Plasma leucine increased in all conditions except COMP and CHO, with LFP demonstrating the highest concentrations (P < 0.05). Postprandial myofibrillar FSR was significantly greater in LFP than in all other conditions (P < 0.05). A modest correlation was observed between peak plasma dileucine concentration (Cmax) and the change in MPS (ΔMPS; r = 0.436, P = 0.037), whereas leucine Cmax showed no significant association (r = 0.265, P = 0.102). Whole-food protein sources generally do not elevate plasma dileucine, except for LFP. While dileucine Cmax correlated with ΔMPS, the modest strength of this relationship suggests that dileucine is likely one of several postprandial factors influencing MPS beyond free leucine.