Carbohydrate beverages attenuate bone resorption markers in elite runners

We evaluated the effects of carbohydrate (CHO) supplementation on markers of bone turnover in elite runners.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 (10×800 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.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, p0.01). 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 (p0.01). 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, p0.001), while an increase from 0.4±0.0 ng/mL to 0.6±0.0 ng/mL (p0.001) was observed in the CON group.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.