Plant Protein Blend Ingestion Stimulates Post-Exercise Myofibrillar Protein Synthesis Rates Equivalently to Whey in Resistance-Trained Adults

ABSTRACT Purpose Whey protein ingestion is typically considered an optimal dietary strategy to maximize myofibrillar protein synthesis (MyoPS) following resistance exercise. While single source plant protein ingestion is typically less effective, at least partly, due to less favorable amino acid profiles, this could theoretically be overcome by blending plant-based proteins with complementary amino acid profiles. We compared the post-exercise MyoPS response following the ingestion of a novel plant-derived protein blend with an isonitrogenous bolus of whey protein. Methods Ten healthy, resistance trained, young adults (male/female: 8/2; age: 26 ± 6 y; BMI: 24 ± 3 kg·m -2 ) received a primed continuous infusion of L-[ ring - 2 H 5 ]-phenylalanine and completed a bout of bilateral leg resistance exercise before ingesting 32 g protein from whey (WHEY) or a plant protein blend (BLEND; 39.5% pea, 39.5% brown rice, 21.0% canola) in a randomized, double-blind crossover fashion. Blood and muscle samples were collected at rest, and 2 and 4 h after exercise and protein ingestion, to assess plasma amino acid concentrations, and postabsorptive and post-exercise MyoPS rates. Results Plasma essential amino acid availability over the 4 h postprandial post-exercise period was ~44% higher in WHEY compared with BLEND ( P = 0.04). From equivalent postabsorptive values (WHEY, 0.042 ± 0.020%·h −1 ; BLEND, 0.043 ± 0.015%·h −1 ) MyoPS rates increased following exercise and protein ingestion (time effect; P < 0.001) over a 0-2 h (WHEY, 0.085 ± 0.037%·h −1 ; BLEND, 0.080 ± 0.037%·h −1 ) and 2-4 h (WHEY, 0.085 ± 0.036%·h −1 ; BLEND, 0.086 ± 0.034%·h −1 ) period, with no differences between conditions during either period or throughout the entire (0-4 h) postprandial period (time × condition interactions; all P > 0.05). Conclusions Ingestion of a novel plant-based protein blend stimulates post-exercise MyoPS to an equivalent extent as a whey protein, demonstrating the utility of plant protein blends to optimize post-exercise skeletal muscle reconditioning.