The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism
REBECCA TOWNSEND, KIRSTY J. ELLIOTT-SALE, KEVIN CURRELL, JONATHAN TANG, WILLIAM D. FRASER, CRAIG SALE
2017
Medicine & Science in Sports & Exercise
Purpose 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. Methods 10 men (age 28±5 y, height 1.74±0.05 m, body mass 69.7±6.3 kg) performed treadmill running at 75%VO 2max , until exhaustion, on three occasions. Blood was collected before and immediately, 1, 2, 3, 4 and 24 h post-exercise, for measurement of β-CTX, P1NP, PTH, PO 4 , ACa and Ca 2+ . This was a randomised,
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... alanced, placebo-controlled, single-blinded, cross-over study. The three trials were; i) placebo (PLA), PLA solution was ingested immediately and 2 h post-exercise, ii) immediate feeding (IF), CHO+PRO (1.5 g . kgBM -1 dextrose and 0.5 g . kgBM -1 whey) were ingested immediately post-exercise and PLA 2 h postexercise, and iii) delayed feeding (DF), PLA was ingested immediately post-exercise and CHO+PRO solution 2 h post-exercise. Data were analysed using repeated measures ANOVA and post-hoc Tukey's HSD. Results At 1 and 2 h post-exercise, β-CTX concentrations were lower in the IF trial than the DF and PLA trials (P≤0.001). At 3 h post-exercise, β-CTX concentrations were higher in the PLA trial than the IF (P≤0.001) and DF trials (P=0.026). At 4 h post-exercise, β-CTX concentrations were lower in the DF trial than the IF (P=0.003) and PLA trials (P≤0.001). At 4 h post-exercise, P1NP was higher in the IF trial than in DF (P=0.026) and PLA trials (P=0.001). At 3 h post-exercise, PTH was higher in the IF trial than the DF trial (P≤0.001). Following 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. There was no main effect of Trial for albumin, but there was for Time (P≤0.001; = 0.372) and there was no Trial x Time interaction (P=0.054; = 0.167). Overall mean albumin concentrations were significantly increased from baseline by the end of exercise (+3 to +4%; P=0.011). There were no other significant changes in albumin concentrations (Figure 4 ). Discussion The main findings of the study are that: 1) ingestion of the CHO+PRO solution containing 1.5 g . kgBM -1 of CHO and 0.5 g . kgBM -1 of PRO suppressed β-CTX concentrations following an exhaustive run, with a greater overall suppression when the CHO+PRO solution was ingested immediately; 2) immediate ingestion of the CHO+PRO solution resulted in small increases in P1NP concentrations at 3 and 4 h post-exercise; 3) delayed ingestion of the CHO+PRO solution (2 h post-exercise) also resulted in a large suppression of β-CTX concentrations. These findings are novel and have the potential to directly influence an athlete's dietary and/or training practices. The response in the PLA trial, showed that the exhaustive running bout caused an immediate increase in bone turnover at the end of exercise, indicated by increased β-CTX and P1NP concentrations above baseline. This was followed by decreased bone turnover during recovery, indicated by decreased β-CTX and P1NP concentrations below baseline. Ingestion of the CHO+PRO solution immediately post-exercise caused a rapid and prolonged (at least 4 h) suppression of β-CTX concentrations below baseline levels (-22 to -61%), whereas ingesting the PLA solution immediately post-exercise meant that β-CTX concentrations were increased above baseline by between +7 and +15%. When ingestion of the CHO+PRO was delayed by 2 h, it caused suppression of β-CTX concentrations below baseline (-44 to -65%), which is similar to the suppression caused by immediate ingestion of the CHO+PRO solution and it occurred within the same timeframe, i.e., 1 -2 h after ingestion. 29. Sale C, Varley I, Jones TW, et al. Effect of carbohydrate feeding on the bone metabolic response to running. 38. Walsh JS, Henriksen DB. Feeding and bone. Arch Biochem Biophys. 2010; 503(1):11-9. 39. Warden SJ, Burr DB, Brukner PD. Stress fractures: pathophysiology, epidemiology, and risk factors. Current osteoporosis reports. 2006; 4(3):103-9. 40. Zittermann A, Sabatschus O, Jantzen S, Platen P, Danz A, Stehle P. Evidence for an acute rise of intestinal calcium absorption in response to aerobic exercise. Eur J Nutr. 2002; 41(5):189-96.
doi:10.1249/mss.0000000000001211
pmid:28121797
fatcat:qojc6btpcfegzksnrqhqac6ztq