Carbohydrate beverages attenuate bone resorption markers in elite runners

Objective. We evaluated the effects of carbohydrate (CHO) supplementation on markers of bone turnover in elite runners. Design. Twenty-four male runners were randomly assigned to two groups - a CHO and a control (CON) group - using a double-blind design. The participants were submitted to an overload training program (days 1-8), followed by a high-intensity intermittent running protocol (10 x 800 m) on day 9. They received a maltodextrin solution (CHO group) or a placebo solution as the CON equivalent, before, during, and after these protocols. Results. After 8 days of intensive training, baseline levels of osteocalcin (OC) decreased in both CHO and CON groups (before: 28.8 +/- 3.6 and 26.6 +/- 2.4 ng/ml, after: 24.8 +/- 3.0 and 21.9 +/- 1.6 ng/ml, respectively, p < 0.01). On day 9, at 80 min of the recovery period, carboxy-terminal of telopeptide type I collagen (CTX) serum concentration was suppressed in the CHO group (0.3 +/- 0.1 ng/ml) vs. 0.6 +/- 0.0 ng/ml for the CON group (p < 0.01). CHO supplementation was effective in decreasing CTX levels from baseline to recovery (0.5 +/- 0.1 ng/mL to 0.3 +/- 0.1 ng/mL, p < 0.001), while an increase from 0.4 +/- 0.0 ng/mL to 0.6 +/- 0.0 ng/mL (p < 0.001) was observed in the CON group. Conclusion. CHO beverage ingestion attenuated the exercise-induced increase in CTX concentration, suggesting that CHO supplementation is a potential strategy to prevent bone damage in athletes. (C) 2014 Elsevier Inc. All rights reserved.