title: Carbohydrate beverages attenuate bone resorption markers in elite runners.
abstract: OBJECTIVE
  We evaluated the effects of carbohydrate (CHO) supplementation on markers of bone turnover in elite runners.
  
  
  METHODS
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Laboratory of Medical Investigation 18 - LIM-18, Endocrinology Division, Medical School, University of São Paulo, SP, Brazil. Electronic address: maysavs@uol.com.br.
authors.forename: Maysa Vieira
authors.initials: MV
authors.lastname: de Sousa
authors.affiliation: Bone Metabolism Laboratory, Rheumatology Division, Medical School, University of São Paulo, SP, Brazil.
authors.forename: Rosa Maria R
authors.initials: RM
authors.lastname: Pereira
authors.affiliation: Laboratory of Medical Investigation 18 - LIM-18, Endocrinology Division, Medical School, University of São Paulo, SP, Brazil.
authors.forename: Rosa
authors.initials: R
authors.lastname: Fukui
authors.affiliation: Bone Metabolism Laboratory, Rheumatology Division, Medical School, University of São Paulo, SP, Brazil.
authors.forename: Valéria Falco
authors.initials: VF
authors.lastname: Caparbo
authors.affiliation: Laboratory of Medical Investigation 18 - LIM-18, Endocrinology Division, Medical School, University of São Paulo, SP, Brazil.
authors.forename: Maria Elizabeth Rossi
authors.initials: ME
authors.lastname: da Silva
mesh_terms: D000328:Adult; D056352:Athletes; D001628:Beverages; D015415:Biomarkers / Q000378:metabolism; D001823:Body Composition; D001862:Bone Resorption / Q000378:metabolism* / Q000517:prevention & control*; D024042:Collagen Type I / Q000097:blood; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010806:Physical Education and Training; D012420:Running / Q000502:physiology*
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D004040:Dietary Carbohydrates; D015675:Osteocalcin
keywords: Bone turnover markers; CTX; Carbohydrate supplementation; Exercise; PTH