Mycoprotein ingestion within or without its wholefood matrix results in equivalent stimulation of myofibrillar protein synthesis rates in resting and exercised muscle of young men

<jats:title>Abstract</jats:title><jats:p>Ingestion of mycoprotein stimulates skeletal muscle protein synthesis (MPS) rates to a greater extent than concentrated milk protein when matched for leucine content, potentially attributable to the wholefood nature of mycoprotein. We hypothesised that bolus ingestion of mycoprotein as part of its wholefood matrix would stimulate MPS rates to a greater extent compared with a leucine-matched bolus of protein concentrated from mycoprotein. Twenty-four healthy young (age, 21 ± 2 years; BMI, 24 ± 3 kg.m<jats:sup>2</jats:sup>) males received primed, continuous infusions of L-[<jats:italic>ring</jats:italic>-<jats:sup>2</jats:sup>H<jats:sub>5</jats:sub>]phenylalanine and completed a bout of unilateral resistance leg exercise before ingesting either 70 g mycoprotein (MYC; 31·4 g protein, 2·5 g leucine; <jats:italic>n</jats:italic> 12) or 38·2 g of a protein concentrate obtained from mycoprotein (PCM; 28·0 g protein, 2·5 g leucine; <jats:italic>n</jats:italic> 12). Blood and muscle samples (<jats:italic>vastus lateralis</jats:italic>) were taken pre- and (4 h) post-exercise/protein ingestion to assess postabsorptive and postprandial myofibrillar protein fractional synthetic rates (FSR) in resting and exercised muscle. Protein ingestion increased plasma essential amino acid and leucine concentrations (<jats:italic>P</jats:italic> &lt; 0·0001), but more rapidly (both 60 <jats:italic>v</jats:italic>. 90 min; <jats:italic>P</jats:italic> &lt; 0·0001) and to greater magnitudes (1367 <jats:italic>v</jats:italic>. 1346 μmol·l<jats:sup>–1</jats:sup> and 298 <jats:italic>v</jats:italic>. 283 μmol·l<jats:sup>–1</jats:sup>, respectively; <jats:italic>P</jats:italic> &lt; 0·0001) in PCM compared with MYC. Protein ingestion increased myofibrillar FSR (<jats:italic>P</jats:italic> &lt; 0·0001) in both rested (MYC, Δ0·031 ± 0·007 %·h<jats:sup>–1</jats:sup> and PCM, Δ0·020 ± 0·008 %·h<jats:sup>–1</jats:sup>) and exercised (MYC, Δ0·057 ± 0·011 %·h<jats:sup>–1</jats:sup> and PCM, Δ0·058 ± 0·012 %·h<jats:sup>–1</jats:sup>) muscle, with no differences between conditions (<jats:italic>P</jats:italic> &gt; 0·05). Mycoprotein ingestion results in equivalent postprandial stimulation of resting and post-exercise myofibrillar protein synthesis rates irrespective of whether it is consumed within or without its wholefood matrix.</jats:p>