The effect of dietary pattern and creatine supplementation on regulating skeletal muscle mass

Skeletal muscle plays a vital role in supporting physical performance and metabolic health. Thus, defining more effective strategies to augment (or maintain) the amount and quality of skeletal muscle protein mass is relevant to support physical performance and prevent poor health. Skeletal muscle protein turnover, or the rate at which muscle proteins are synthesized and broken down, is the primary process by which skeletal muscle can remodel to facilitate the replacement of damaged or ‘old’ proteins to ensure a ‘healthy’ skeletal muscle proteome. Importantly, regular exercise and protein ingestion are two anabolic stimuli capable of augmenting muscle protein turnover primarily by stimulating muscle protein synthesis rates. Indeed, not all protein foods are alike in terms of their amino acid composition and digestibility. Specifically, animal-derived protein foods are typically of higher quality as determined by their higher essential amino acid content and improved digestibility and amino acid absorption rates when compared to plant-derived protein foods. Moreover, it is believed that distribution of dietary protein intake throughout the day may be an important regulatory factor for the stimulation of muscle protein synthesis rates. Nevertheless, most studies investigating the effect of various feeding interventions on the stimulation of postprandial muscle protein synthesis rates have focused on single-meal responses in a well-controlled laboratory setting as opposed to examining dietary patterns, which consists of consuming multiple meals over the course of the day. Ergogenic dietary supplements are also often incorporated into a dietary pattern in an attempt to augment muscle protein synthesis rates and further improve the skeletal muscle adaptive response, particularly alongside an exercise training regimen. Creatine supplementation is one of the most popular dietary supplements and it is often chemically modified and brought to market as an analog claiming to boost the efficacy on skeletal muscle. In study 1, we demonstrated that a vegan dietary pattern results in similar integrated daily myofibrillar protein synthesis rates compared to an omnivorous dietary pattern. We further demonstrated that protein distribution (evenness of protein intake and number of meals) had no effect on regulating changes in myofibrillar protein synthesis rates irrespective of eating an animal or vegan based dietary pattern. As a secondary outcome, we established that omnivorous dietary patterns result in greater feelings of pleasantness but lower feelings of energy and tiredness compared to the vegan dietary pattern. In study 2, we demonstrated that a novel analog of creatine (creatyl-L-leucine) failed to augment muscle creatine content compared to the well-researched form of creatine monohydrate. Overall, the studies contained in this dissertation investigated various dietary factors and offers novel insights into the role of dietary patterns and creatine supplementation in supporting skeletal muscle protein turnover and creatine content in healthy young adults.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Kinesiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Askow, Andrew Tyler Mitchell

Contributors dc:contributor

• Burd, Nicholas A
• Allen, Jacob M
• Petruzzello, Steven J
• Wall, Benjamin T

• Heavy Water
• Protein Source
• Protein Distribution
• Muscle Protein Synthesis Rate
• Omnivorous
• Vegan

Statement dc:rights

• Copyright 2024 Andrew Askow

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127250

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127250