Essential Amino Acid Ingestion Facilitates Leucine Retention and Attenuates Myofibrillar Protein Breakdown following Bodyweight Resistance Exercise in Young Adults in a Home-Based Setting

Nutrients. 2022 Aug 27;14(17):3532. doi: 10.3390/nu14173532.

Abstract

Home-based resistance exercise (RE) has become increasingly prevalent, but its effects on protein metabolism are understudied. We tested the effect of an essential amino acid formulation (EAA+: 9 g EAAs, 3 g leucine) and branched-chain amino acids (BCAAs: 6 g BCAAs, 3 g leucine), relative to a carbohydrate (CHO) placebo, on exogenous leucine retention and myofibrillar protein breakdown following dynamic bodyweight RE in a home-based setting. Twelve recreationally active adults (nine male, three female) participated in a double-blind, placebo-controlled, crossover study with four trial conditions: (i) RE and EAA+ (EX-EAA+); (ii) RE and BCAAs (EX-BCAA); (iii) RE and CHO placebo (EX-CHO); and (iv) rest and CHO placebo (REST-CHO). Total exogenous leucine oxidation and retention (estimates of whole-body anabolism) and urinary 3-methylhistidine:creatinine ratio (3MH:Cr; estimate of muscle catabolism) were assessed over 5 h post-supplement. Total exogenous leucine oxidation and retention in EX-EAA+ and EX-BCAA did not significantly differ (p = 0.116) but were greater than EX-CHO (p < 0.01). There was a main effect of condition on urinary 3MH:Cr (p = 0.034), with post hoc analysis revealing a trend (p = 0.096) for reduced urinary 3MH:Cr with EX-EAA+ (32%) compared to EX-CHO. By direct comparison, urinary 3MH:Cr was significantly lower (23%) in EX-EAA+ than EX-BCAA (p = 0.026). In summary, the ingestion of EAA+ or BCAA provided leucine that was ~60% retained for protein synthesis following home-based bodyweight RE, but EAA+ most effectively attenuated myofibrillar protein breakdown.

Keywords: bodyweight; essential amino acids; home-based; oxidation; protein metabolism; resistance exercise.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Amino Acids, Essential* / administration & dosage
  • Cross-Over Studies
  • Double-Blind Method
  • Eating
  • Female
  • Humans
  • Leucine* / metabolism
  • Male
  • Muscle Proteins* / metabolism
  • Myofibrils* / metabolism
  • Resistance Training*
  • Young Adult

Substances

  • Amino Acids, Essential
  • Muscle Proteins
  • Leucine