Mycoprotein ingestion stimulates protein synthesis rates to a greater extent than milk protein in rested and exercised skeletal muscle of healthy young men: a randomized controlled trial.

Background Mycoprotein is a fungal-derived sustainable protein-rich food source, and its ingestion results in systemic amino acid and leucine concentrations similar to that following milk protein ingestion. Objective We assessed the mixed skeletal muscle protein synthetic response to the ingestion of a single bolus of mycoprotein compared with a leucine-matched bolus of milk protein, in rested and exercised muscle of resistance-trained young men. Methods Twenty resistance-trained healthy young males (age: 22 ± 1 y, body mass: 82 ± 2 kg, BMI: 25 ± 1 kg·m⁻²) took part in a randomized, double-blind, parallel-group study. Participants received primed, continuous infusions of L-[ring-²H₅]phenylalanine and ingested either 31 g (26.2 g protein: 2.5 g leucine) milk protein (MILK) or 70 g (31.5 g protein: 2.5 g leucine) mycoprotein (MYCO) following a bout of unilateral resistance-type exercise (contralateral leg acting as resting control). Blood and m. vastus lateralis muscle samples were collected before exercise and protein ingestion, and following a 4-h postprandial period to assess mixed muscle fractional protein synthetic rates (FSRs) and myocellular signaling in response to the protein beverages in resting and exercised muscle. Results Mixed muscle FSRs increased following MILK ingestion (from 0.036 ± 0.008 to 0.052 ± 0.006%·h⁻¹ in rested, and 0.035 ± 0.008 to 0.056 ± 0.005%·h⁻¹ in exercised muscle; P  <0.01) but to a greater extent following MYCO ingestion (from 0.025 ± 0.006 to 0.057 ± 0.004%·h⁻¹ in rested, and 0.024 ± 0.007 to 0.072 ± 0.005%·h⁻¹ in exercised muscle; P  <0.0001) (treatment × time interaction effect; P  <0.05). Postprandial FSRs trended to be greater in MYCO compared with MILK (0.065 ± 0.004 compared with 0.054 ± 0.004%·h⁻¹, respectively; P  = 0.093) and the postprandial rise in FSRs was greater in MYCO compared with MILK (Delta 0.040 ± 0.006 compared with Delta 0.018 ± 0.005%·h⁻¹, respectively; P  <0.01). Conclusions The ingestion of a single bolus of mycoprotein stimulates resting and postexercise muscle protein synthesis rates, and to a greater extent than a leucine-matched bolus of milk protein, in resistance-trained young men. This trial was registered at clinicaltrials.gov as 660065600. [ABSTRACT FROM AUTHOR]