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Cited by 147Muscle metabolism and nutritionSports Performance and TrainingCardiovascular and exercise physiology

Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise

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Koopman, René, Pannemans, Daphne L. E., Jeukendrup, Asker E., Gijsen, Annemie P., Senden, Joan M. G., Halliday, David, Saris, Wim H. M., van Loon, Luc J. C. +1 more·2004·American Journal of Physiology-Endocrinology and Metabolism
DOI 10.1152/ajpendo.00543.2003
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Abstract

The aims of this study were to compare different tracer methods to assess whole body protein turnover during 6 h of prolonged endurance exercise when carbohydrate was ingested throughout the exercise period and to investigate whether addition of protein can improve protein balance. Eight endurance-trained athletes were studied on two different occasions at rest (4 h), during 6 h of exercise at 50% of maximal O 2 uptake (in sequential order: 2.5 h of cycling, 1 h of running, and 2.5 h of cycling), and during subsequent recovery (4 h). Subjects ingested carbohydrate (CHO trial; 0.7 g CHO·kg−1·h−1) or carbohydrate/protein beverages (CHO + PRO trial; 0.7 g CHO·kg−1·h−1 and 0.25 g PRO·kg−1·h−1) at 30-min intervals during the entire study. Whole body protein metabolism was determined by infusion of l-[1-13 C]leucine, l-[2 H 5]phenylalanine, and [15 N 2]urea tracers with sampling of blood and expired breath. Leucine oxidation increased from rest to exercise [27 ± 2.5 vs. 74 ± 8.8 (CHO) and 85 ± 9.5 vs. 200 ± 16.3 mg protein·kg−1·h−1(CHO + PRO), P < 0.05], whereas phenylalanine oxidation and urea production did not increase with exercise. Whole body protein balance during exercise with carbohydrate ingestion was negative (−74 ± 8.8, −17 ± 1.1, and −72 ± 5.7 mg protein·kg−1·h−1) when l-[1-13 C]leucine, l-[2 H 5]phenylalanine, and [15 N 2]urea, respectively, were used as tracers. Addition of protein to the carbohydrate drinks resulted in a positive or less-negative protein balance (−32 ± 16.3, 165 ± 4.6, and 151 ± 13.4 mg protein·kg−1·h−1) when l-[1-13 C]leucine, l-[2 H 5]phenylalanine, and [15 N 2]urea, respectively, were used as tracers. We conclude that, even during 6 h of exhaustive exercise in trained athletes using carbohydrate supplements, net protein oxidation does not increase compared with the resting state and/or postexercise recovery. Combined ingestion of protein and carbohydrate improves net protein balance at rest as well as during exercise and postexercise recovery.

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Authors
Koopman, R., Pannemans, D. L. E., Jeukendrup, A. E., Gijsen, A. P., Senden, J. M. G., Halliday, D., Saris, W. H. M., van Loon, L. J. C., & Wagenmakers, A. J. M.
Affiliations
Maastricht University (NL)
ORCID
Venue
American Journal of Physiology-Endocrinology and Metabolism
Publisher
American Physiological Society
Published
2004-10
Volume
287
Issue
4
Pages
E712-E720
ISSN
  • 0193-1849 (ISSN-L)
  • 1522-1555
DOI
10.1152/ajpendo.00543.2003
OpenAlex
W2045204056
Cited by
147
References
41
Citations by year
2026: 1 · 2025: 4 · 2024: 6 · 2023: 1 · 2022: 5 · 2021: 2 · 2020: 4 · 2019: 6 · 2018: 3 · 2017: 6 · 2016: 10 · 2015: 8 · 2014: 8 · 2013: 9 · 2012: 8
FWCI
2.29
Type
journal article
Language
en
Open access
Licence
other-oa
Locations
  • American Journal of Physiology-Endocrinology and Metabolism (publishedVersion)
  • PubMed (publishedVersion)
  • Research Publications (Maastricht University) (publishedVersion, other-oa)
  • University of Birmingham Research Portal (University of Birmingham) (submittedVersion)
  • Research Publications (Maastricht University) (submittedVersion, other-oa)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
Keywords
protein balance, whole-body protein turnover, ultra-endurance exercise, carbohydrate-protein supplementation, leucine oxidation, phenylalanine oxidation, urea synthesis, endurance athletes, post-exercise recovery, nitrogen balance
MeSH terms
Adult, Algorithms, Amino Acids, Beverages, Diet, Dietary Carbohydrates, Dietary Proteins, Humans, Kinetics, Leucine, Male, Oxygen Consumption, Phenylalanine, Physical Endurance, Proteins, Urea, Exercise

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