title: The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism.
abstract: This study aimed to investigate the effect of feeding carbohydrate and protein (CHO + PRO), immediately or 2 h after an exhaustive run, on the bone turnover response in endurance runners.
  
  
  
  Ten men (age = 28 ± 5 yr, height = 1.74 ± 0.05 m, body mass [BM] = 69.7 ± 6.3 kg) performed treadmill running at 75% V˙O2max, until exhaustion, on three occasions. Blood was collected before and immediately, 1, 2, 3, 4, and 24 h postexercise, for measurement of β-CTX, P1NP, parathyroid hormone, PO4, ACa, and Ca. This was a randomized, counterbalanced, placebo-controlled, and single-blinded crossover study. The three trials were (i) placebo (PLA), where the PLA solution was ingested immediately and 2 h postexercise; (ii) immediate feeding (IF), where CHO + PRO (1.5 g·kg BM dextrose and 0.5 g·kg BM whey) was ingested immediately postexercise and PLA 2 h postexercise; and (iii) delayed feeding (DF), where PLA was ingested immediately postexercise and CHO + PRO solution 2 h postexercise. Data were analyzed using repeated-measures ANOVA and Tukey's HSD post hoc test.
  
  
  
  At 1 and 2 h postexercise, β-CTX concentrations were lower in the IF trial compared with the DF and PLA trials (P ≤ 0.001). At 3 h postexercise, β-CTX concentrations were higher in the PLA trial compared with the IF (P ≤ 0.001) and DF trials (P = 0.026). At 4 h postexercise, β-CTX concentrations were lower in the DF trial compared with the IF (P = 0.003) and PLA trials (P ≤ 0.001). At 4 h postexercise, P1NP was higher in the IF trial compared with the DF (P = 0.026) and PLA trials (P = 0.001). At 3 h postexercise, parathyroid hormone was higher in the IF trial compared with the DF trial (P ≤ 0.001).
  
  
  
  After exhaustive running, immediate ingestion of CHO + PRO may be beneficial, as it decreases bone resorption marker concentrations and increases bone formation marker concentrations, creating a more positive bone turnover balance.
authors.affiliation: 1Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UNITED KINGDOM; 2EIS Performance Centre, The English Institute of Sport, Loughborough University, Loughborough, UNITED KINGDOM; 3Norwich Medical School, University of East Anglia, Norfolk, UNITED KINGDOM; and 4Norfolk and Norwich University Hospital, Norwich, UNITED KINGDOM.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Townsend
authors.forename: Kirsty J
authors.initials: KJ
authors.lastname: Elliott-Sale
authors.forename: Kevin
authors.initials: K
authors.lastname: Currell
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tang
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
authors.forename: Craig
authors.initials: C
authors.lastname: Sale
mesh_terms: D000328:Adult; D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D024042:Collagen Type I / Q000097:blood; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012709:Serum Albumin / Q000378:metabolism; D016037:Single-Blind Method
chemical_list: D024042:Collagen Type I; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D010281:Parathyroid Hormone; D010710:Phosphates; D012709:Serum Albumin; D002118:Calcium