Lactalbumin, Not Collagen, Augments Muscle Protein Synthesis with Aerobic Exercise
Authors: Thomas R Tripp
Steven K Baker
Chris McGlory
Martin J Macinnis
Stuart M Phillips
Sara Y Oikawa
Journal: Medicine and science in sports and exercise (2020)
Discipline: CLINICAL MEDICINE
Keywords: Protein ingestion; Hyperaminoacidemia; Skeletal muscle protein synthesis; Muscle remodeling; α-lactalbumin
Affiliations: Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA., Department of Neurology, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, CANADA.

Abstract:  Introduction: Protein ingestion and the ensuing hyperaminoacidemia stimulates skeletal muscle protein synthesis in the postexercise period. This response facilitates muscle remodeling, which is important during intensified training. The aim of this study was to determine whether supplementation with α-lactalbumin (LA), with high leucine and tryptophan contents, would improve responses to short periods of intensified aerobic training compared with supplementation with an isonitrogenous quantity of collagen peptides (CP). Methods: Endurance-trained participants (5 male, 6 female, 24 ± 4 yr, V˙O2 = 53.2 ± 9.1 mL·kg·min, peak power output = 320 ± 48 W; means ± SD) consumed a controlled diet (1.0 g·kg·d protein) and refrained from habitual training for 11 d while taking part in this double-blind randomized, crossover trial. The two intervention phases, which consisted of brief intensified training (4 × 4-min cycling intervals at 70% of peak power output on 3 consecutive days) combined with the ingestion of LA or CP supplements after exercise (20 g) and before sleep (40 g), were separated by 4 d of washout without protein supplementation (i.e., the control phase). In response to each phase, myofibrillar (MyoPS), sarcoplasmic protein synthesis (SarcPS) rates (via H2O ingestion) and parameters of sleep quality were measured. Results: LA ingestion increased plasma leucine (P &lt; 0.001) and tryptophan concentrations (P &lt; 0.001) relative to CP. Intensified training increased MyoPS and SarcPS above the washout phase in LA- and CP-supplemented phases (P &lt; 0.01), with increases being 13% ± 5% and 5% ± 7% greater with LA than CP for MyoPS (P &lt; 0.01) and SarcPS, respectively (P &lt; 0.01). Conclusions: Despite an isonitrogenous diet, protein synthesis was enhanced to a greater extent when trained participants consumed LA compared with CP during intensified aerobic training, suggesting that protein quality is an important consideration for endurance-trained athletes aiming to augment adaption to exercise training. 

Retracted: No

PubPeer comments:
 Copy pasted from https: journals.lww.com acsm-msse Citation 2021 01000 Corrigendum.33.aspx (Medicine Science in Sports Exercise. 53(1):247, January 2021):  The authors of articles (1)u2013(4) below amend their conflict-of-interest statements to include the following: Dr. Stuart M. Phillips is listed as an inventor on patent (Canadian) 3052324 issued to Exerkine, and a patent (US) 16 182891 pending to Exerkine (but reports no financial gains). Dr. Phillips reports personal fees from Enhanced Recovery (donated to charity), equity from Exerkine (all proceeds donated to charity), outside the submitted work. See https: retractionwatch.com 2021 02 12 eleven-papers-corrected-after-nutrition-prof-fails-to-disclose-patent-company-ties for backgrounds. ,