Branched-Chain Amino Acid Fortification Does Not Restore Muscle Protein Synthesis Rates following Ingestion of Lower- Compared with Higher-Dose Mycoprotein

Abstract

Background We have shown that ingesting a large bolus (70 g) of the fungal-derived, whole food mycoprotein robustly stimulates muscle protein synthesis (MPS) rates. Objective The aim of this study was to determine if a lower dose (35 g) of mycoprotein enriched with branched-chain amino acids (BCAAs) stimulates MPS to the same extent as 70 g of mycoprotein in resistance-trained young men. Methods Nineteen men [aged 22 ± 1 y, BMI (kg/m2): 25 ± 1] took part in a randomized, double-blind, parallel-group study. Participants received primed, continuous infusions of l-[ring-2H5]phenylalanine and ingested either 70 g mycoprotein (31.5 g protein; MYCO; n = 10) or 35 g BCAA-enriched mycoprotein (18.7 g protein: matched on BCAA content; ENR; n = 9) following a bout of unilateral resistance exercise. Blood and bilateral quadriceps muscle samples were obtained before exercise and protein ingestion and during a 4-h postprandial period to assess MPS in rested and exercised muscle. Two- and 3-factor ANOVAs were used to detect differences in plasma amino acid kinetics and mixed muscle fractional synthetic rates, respectively. Results Postprandial plasma BCAA concentrations increased more rapidly and to a larger degree in ENR compared with MYCO. MPS increased with protein ingestion (P ≤ 0.05) but to a greater extent following MYCO (from 0.025% ± 0.006% to 0.057% ± 0.004% · h−1 in rested muscle, and from 0.024% ± 0.007% to 0.072% ± 0.005% · h−1 in exercised muscle; P < 0.0001) compared with ENR (from 0.031% ± 0.003% to 0.043% ± 0.005% · h−1 in rested muscle, and 0.027% ± 0.005% to 0.052% ± 0.005% · h−1 in exercised muscle; P < 0.01) ingestion. Postprandial MPS rates were greater in MYCO compared with ENR (P < 0.01). Conclusions The ingestion of lower-dose BCAA-enriched mycoprotein stimulates resting and postexercise MPS rates, but to a lesser extent compared with the ingestion of a BCAA-matched 70-g mycoprotein bolus in healthy young men. This trial was registered at clinicaltrials.gov as 660065600.

How Healthy Are Non-Traditional Dietary Proteins? The Effect of Diverse Protein Foods on Biomarkers of Human Health

“…Myofibrillar protein synthesis was found to be equivalent for mycoprotein compared with animal protein foods and whey protein in both exercised and rested leg muscle [ 69 ]. Mycoprotein stimulated greater post-exercise muscle protein synthesis and was superior in supporting acute tissue remodelling, compared with (lysine-matched) milk protein [ 70 ], whereas enrichment of mycoprotein with branched-chain amino acids (BCAA) failed to further enhance muscle protein synthesis [ 71 ].…”

A mycoprotein-based high-protein vegan diet supports equivalent daily myofibrillar protein synthesis rates compared with an isonitrogenous omnivorous diet in older adults: a randomised controlled trial

“…Future work is required to investigate the impact of a range of vegan protein sources both on acute postprandial and daily MPS rates. Finally, we employed unilateral isodynamic maximal concentric contractions as a model of exercise to ensure a daily stimulation of MPS rates in line with our previous work (30) . We reasoned that this would increase the cumulative stimulatory effect across the 3-d intervention without inducing excessive muscle damage.…”

“…The dominant leg was selected as we deemed it likely that they would be better able to execute contractions in a leg that they were more accustomed to loading and therefore create more mechanical tension (29) . The exercise protocol was selected as we have previously shown that it stimulates MPS rates (30) , allowing us to model the effect on rested tissue alongside exercised tissue. As the exercise is maximally concentric in nature, we would expect it to largely obviate any muscle damage and therefore represent a protein accretional stimulus as opposed to one directed at correcting muscle damage (31) .…”

Fungal-Derived Mycoprotein and Health across the Lifespan: A Narrative Review

“…Eight studies have evaluated the effects of mycoprotein consumption in relation to markers of health in early and young adulthood [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. A range of outcomes were studied including effects of ingestion on the plasma lipidome [ 28 ], cholesterol levels [ 35 ] protein synthesis rates [ 31 , 32 ], postprandial amino acid, glucose and insulin levels [ 29 , 30 , 33 ] and energy intake and appetite [ 34 ].…”

“…Results showed that the myoprotein consumption enhanced postexercise and resting muscle protein synthesis rates to a greater extent than the control [ 31 ]. Similarly, work by the same research group conducted with young males (mean age 22 years) found that a 35 g dose of branched chain amino acid (BCAA) enriched mycoprotein stimulated muscle protein synthesis rates at rest and postexercise but to a lesser extent than the 70 g mycoprotein bolus (BCAA matched) in healthy young men [ 32 ].…”