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Session: Molecular Adaptations to Exercise and Nutrition Interventions (Oral 6)

(OR06-01-23) Essential Amino Acid-Enriched Whey Protein Rescues Post-Exercise Muscle Protein Synthesis During Energy Deficit

Sunday, July 23, 2023
8:00 AM – 8:12 AM ET
Location:  Commonwealth
Disclosure(s):
Jess A. Gwin, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Energy deficiency decreases muscle protein synthesis (MPS), which may result from greater whole-body essential amino acid (EAA) requirements and reliance on EAA to support energy demand. Whether this energy deficit-induced anabolic resistance may be overcome through the provision of acute supplemental energy or if increased EAA are needed to stimulate MPS is unknown. Therefore, we tested the effects of supplemental energy in the forms of EAA or carbohydrate, combined with an EAA-enriched whey protein, on post-exercise MPS and whole-body protein turnover.

Methods: 17 adults (mean±SD; age: 26±6y, BMI: 25±3 kg/m2) completed a randomized, double-blind parallel study including two 5d energy conditions (BAL, energy balance; DEF, 30±3% energy requirements) separated by ≥7d. Volunteers consumed either an EAA-enriched whey beverage with added EAA (+EAA; 304kcal, 56g protein, 48g EAA, 17g carbohydrate, 2g fat, n=8) or with added carbohydrate (+CHO; 311kcal, 34g protein, 24g EAA, 40g carbohydrate, 2g fat, n=9) immediately after 60 min of load carriage (59±4%VO2peak) and alternating step ups (9 sets x 16 repetitions). Post-exercise MPS and whole-body protein synthesis (PS), breakdown (PB), and net balance (NET; PS-PB) were estimated using 2H5-phenylalanine and 2H2-tyrosine kinetics.

Results: Within treatments, MPS (%/h) was similar across conditions (+EAA: BAL, 0.073±0.02 vs. DEF, 0.083±0.02, P=0.359 and +CHO: BAL,0.081±0.03 vs. DEF, 0.059±0.01; P=0.056). Between treatments, MPS did not differ during BAL (P=0.45), but was higher in +EAA than +CHO (P=0.015) during DEF. Under both conditions, PS (g protein/240min) was higher in +EAA (BAL, 117.9±16.5; DEF, 110.3±14.8) than +CHO (BAL, 81.6±8.0; DEF, 83.8±5.9; both P < 0.001). Regardless of condition, PB (g protein/240min) was less in +EAA (8.0±16.5) than +CHO (37.8±7.6; P < 0.001). Regardless of condition, NET (g protein/240min) was higher in +EAA (106.1±6.3) than +CHO (44.8±8.5, P</em> < 0.001).

Conclusions: These data suggest that enhancing an EAA-enriched whey protein with supplemental energy in the form of EAA, and not carbohydrate, counters anabolic resistance and maintains postprandial MPS during energy deficit.

Funding Sources: Supported by USAMRDC. Opinions or assertions contained herein are the private views of the authors and not official or reflecting the views of the Army or the Department of Defense.