Influence of the dietary protein source on the long-term resistance training adaptations

Author(s)

Victoria María de Los Ángeles Hevia Larraín

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola de Educação Física e Esportes (EEFE/BT)
• Defense date: 2019-11-14

Examining board members

Hamilton Augusto Roschel da Silva; Guilherme Giannini Artioli; Erick Prado de Oliveira; Gustavo Duarte Pimentel

• Advisor: Hamilton Augusto Roschel da Silva

Abstract

Muscle protein synthesis depends on post-prandial availability of essential amino acids to muscle, particularly leucine which differs significantly between protein sources. Several acute studies show consistently a lower anabolic response of plant- vs. animal-based proteins. However, the effects of an exclusive plant-based dietary protein diet on resistance training- induced adaptations are currently unknown. Then, the aim of the study was to assess the impact of dietary protein source (plant-based proteins vs. mixed protein sources) on resistance training-induced muscle mass and strength in total protein-matched healthy young men. Nineteen (n=19) vegan (VEG 26±5 y; 72.7±7.1 kg, 1.78±0.05 m) and nineteen (n=19) omnivores (OMN 26±4 y; 73.3±7.8 kg, 1.76±0.06 m) physically active young men were enrolled in a 12-week, twice weekly, supervised lower-limb resistance training program. Six 24-h dietary recalls were performed at baseline (for habitual protein intake determination) and then protein intake was individually increased to 1.6 g .kg-1d-1 in both groups via supplementing either soy (VEG) or whey (OMN) protein. 24-h dietary recalls were performed every four weeks throughout the intervention for monitoring purposes. PRE and POST the 12- week intervention, participants were assessed for leg lean mass (LLM, by DXA), rectus femoris and vastus lateralis cross-sectional area (mCSA, by ultrasound) type I and type II fiber cross-sectional area (fCSA, by muscle biopsy), and lower-limb muscle strength (1-RM, by leg-press 1-RM). Both groups met the protein intake target of 1.6 g .kg-1d-1 throughout the intervention, showing just main effect of time respect to PRE values (p<0.0001). Both groups significantly increased LLM (VEG: &#8710;1.2 ± 1.0 kg; OMN: &#8710;1.2 ± 0.8 kg), rectus femoris mCSA (VEG: &#8710;1.1 ± 0.6 cm2 ; OMN: &#8710;0.9 ± 0.5 cm2), vastus lateralis mCSA (VEG: &#8710;2.2 ± 1.1 cm2 ; OMN: &#8710;2.8 ± 1.0 cm2), type I fCSA (VEG: &#8710;741 ± 323 &#8710;m2 ; OMN: &#8710;677 ± 617 &#8710;m2), type II fCSA (VEG: &#8710;921 ± 458 &#8710;m2; OMN: &#8710;844 ± 638 &#8710;m2), and 1-RM (VEG: &#8710;97 ± 38 kg; OMN: &#8710;117 ± 35 kg) across the intervention (all p<0.05), with no between- difference at POST. We conclude that a higher protein-content (1.6 g .kg-1d-1) exclusive plant- based (including soy) protein diet is similarly effective as a mixed diet containing animal- based protein in supporting resistance training-induced muscle adaptations, suggesting that the protein source is not a key determinant for muscle adaptations in untrained young individuals consuming optimal protein intake (AU)

• FAPESP's process: 16/22083-3 - The influence of the dietary protein source on long-term resistance training-induced changes
• Grantee: Victoria María de Los Ángeles Hevia Larraín
• Support Opportunities: Scholarships in Brazil - Master