Post-Exercise Protein Ingestion Increases Whole Body Leucine Balance in a Dose-Dependent Manner in Healthy Children
Bibliographic record
Abstract
PURPOSE: Post-exercise protein ingestion increases whole body protein balance in healthy children early in recovery (i.e., 9 h), although the optimal single meal protein dose has yet to be determined. Therefore, we employed, for the first time in active children, a primed constant [13C]leucine infusion to determine with greater accuracy and time resolution the effect of variable protein ingestion on post-exercise whole body leucine metabolism. METHODS: Thirty-five active children (26 males; 9-13 y, 44.9 ± 10.6 kg; means ± SD) underwent a 5-day adaptation diet (0.95 g protein·kg-1·d-1) before performing an acute bout of exercise (3x20min cycling) with concurrent primed constant infusion of [13C]leucine. After exercise, participants consumed an isoenergetic (140 kcal) carbohydrate beverage containing a variable amount of milk-protein [0g, CONT; 5g, LP; 10g, MP; and 15 g, HP] enriched with [2H3]leucine to a level of 4 % of beverage leucine content (assuming 10% leucine content of protein). Blood and breath samples were taken over 3h of recovery to determine whole body leucine oxidation (LeuOX) and net balance (LeuBAL). RESULTS: Total leucine intake (drink + infusion) was: 6.2 ± 0.2 mg·kg-1 (CONT); 18.4 ± 2.5 mg·kg-1 (LP); 29.0 ± 4.2 mg·kg-1 (MP); 40.8 ± 8.8 mg·kg-1 (HP). LeuBAL showed a main effect for condition [HP (24.2 ± 8.2 mg·kg-1) > MP (11.6 ± 4.3 mg·kg-1) > LP (5.7 ± 1.9 mg·kg-1) > CONT (-3.0 ± 1.7 mg·kg-1); all P < 0.01], with all conditions different from zero (all P < 0.001). Linear correlation (r2=0.69, P < 0.001) indicated LeuBAL became positive at ~10 mg·kg-1 leucine intake. Bi-phase regression analyses (r2=0.68) revealed LeuOX reached a plateau at ~34 mg·kg-1·3h-1 leucine intake, which could suggest leucine intakes above this level represented a nutrient overload in our population over the 3h post-exercise period. CONCLUSION: During the 3h post-exercise recovery period, LeuBAL (a surrogate for net protein balance) was negative in the absence of protein ingestion. Consumption of high quality protein increased LeuBAL in a dose-dependent manner; however, 5-10g may be optimal to promote post-exercise whole body protein recovery as an apparent saturation in the oxidative disposal of leucine suggests leucine intakes above ~34mg/kg in healthy children may provide no further benefit. Study funded by Nestec Ltd.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".