Nutritionally non-essential amino acids are dispensable for whole-body protein synthesis after exercise in endurance athletes with an adequate essential amino acid intake

Abstract

The increased protein requirement of endurance athletes may be related to the need to replace exercise-induced oxidative losses, especially of the branched-chain amino acids (BCAA). However, it is unknown if non-essential amino acids (NEAA) influence the requirement for essential amino acids (EAA) during post-exercise recovery. Seven endurance-trained males ran 20 km prior to consuming [13C]phenylalanine, sufficient energy, and: (1) deficient protein (BASE); (2) BASE supplemented with sufficient BCAA (BCAAsup); (3) an equivalent EAA intake as BCAA (LowEAA), and; (4) sufficient EAA intake (HighEAA). [13C]Phenylalanine oxidation (the reciprocal of protein synthesis) for BCAAsup and HighEAA (0.54 ± 0.15, 0.49 ± 0.11 µmol kg−1 h−1; Mean ± SD) were significantly lower than BASE (0.74 ± 0.14 µmol kg−1 h−1P < 0.01 for both) and LowEAA (0.70 ± 0.11 µmol kg−1 h−1P < 0.05 and 0.01, respectively). Our results suggest that exogenous NEAA are dispensable for whole-body protein synthesis during recovery from endurance exercise provided sufficient EAA are consumed. Endurance athletes who may be at risk of not meeting their elevated protein requirements should prioritize the intake of EAA-enriched foods and/or supplements.

Keywords

Endurance training Amino acid requirement Post-exercise recovery Protein synthesis Non-essential amino acids 

Abbreviations

BASE

Low protein diet

BCAA

Branched-chain amino acids

BCAAsup

BASE supplemented branched-chain amino acids

EAA

Essential amino acid

EEE

Exercise-induced energy expenditure

F13CO2

13CO2 excretion

FFM

Fat-free mass

FM

Fat mass

HighEAA

High dose of essential amino acids

HR

Heart rate

IAAO

Indicator amino acid oxidation

LowEAA

Low dose of essential amino acids

NEAA

Non-essential amino acid

OX

Phenylalanine oxidation

Q

Whole-body phenylalanine flux

RDA

Recommended daily allowance

REE

Resting energy expenditure

VCO2

CO2 production


Autor / Fonte:Hiroyuki Kato, Kimberly A Volterman, Daniel W D West, Katsuya Suzuki, Daniel R Moore Amino Acids 2018 August 25
Link: https://link.springer.com/article/10.1007/s00726-018-2639-y