The effects of dietary protein intake on osteokine, bone turnover, and inflammatory biomarker concentrations in endurance runners
Bibliographic record
Abstract
Introduction. Bone stress injuries are common in endurance athletes due to elevated training volume and energetic demands. Endurance training with inadequate recovery triggers the inflammatory response, together, this upregulates bone resorption for hours and days. The objective of this thesis was: 1) to provide an overview of the evidence on the effects of endurance exercise and dietary protein intake on osteokines, bone turnover, and inflammatory markers in endurance athletes, and 2) to examine the acute effects of immediate post-exercise protein supplementation on serum concentrations of osteokine (sclerostin, nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), dickkopf-1 (DKK1)) and inflammatory markers (interleukin-6 (IL-6), IL-1β, tumor necrosis factor-alpha (TNF-α)).Methods. This was a randomized crossover, within-subject, double-blinded, repeated measures design study in 14 young male and female (n=7 each) endurance runners with a weekly mileage of ≥40 km for the past 6-months. Participants underwent (i) a protein trial (whey), and (ii) a control trial (water); to be consumed immediately after a run to volitional exhaustion at 70% maximal oxygen consumption (VO2max). Blood samples were taken at baseline, immediately after, 1, 2, 3, 4, and 24-hours post-exercise. A linear mixed model assessed the effects of time and condition for each marker, and any interactions (sex, sequence, period, and baseline difference as covariates). Changes from baseline to each post-exercise time point were examined for potential marker associations using Spearman’s rank correlations.Results. Participants had a mean age of 26.6 ± 4.5 years, lean body mass of 50.9 ± 11.7 kg, and VO2max of 59.8 ± 9.2 kg/ml/min. There were no significant effects of condition by time for any osteokine or inflammatory markers. There was a significant main effect of time for sclerostin (p<0.001), OPG (p=0.026), DKK1 (p=0.655), TNF-α (p=0.699), and IL-1β (p=0.862). Conclusions. This thesis suggests that the crosstalk between the skeletal and immune systems exists during and after acute and chronic exercise in endurance athletes, and dietary protein intake (mostly when consumed with other nutrients) may attenuate bone resorption and pro-inflammatory markers. However, dietary protein intake alone had no effect on osteokine and inflammatory responses following exhaustive exercise compared to the control treatment. Endurance athletes should consider combining dietary protein with other nutrients (e.g., carbohydrates, calcium-rich foods and beverages) before and after exercise for optimal bone health recovery. Future research should compare nutritional interventions (e.g., pre and/or post-exercise protein vs protein and carbohydrates vs control) in a larger sample of endurance athletes and investigate sex differences
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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) | 0.001 | 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) | 0.002 | 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".