title: Fasting and energy intake influence bone turnover in lightweight male rowers.
abstract: The purpose of this study was to investigate the influence of an acute 24-hr fast versus usual 24-hr dietary intake on markers of bone turnover in collegiate lightweight male rowers. Bone turnover was measured by serum osteocalcin (OC) and urinary excretion of pyridinium cross-links (pyridinoline [PYD¿ and deoxypyridinoline ¿DPD]). Fasting subjects (F) (n = 14) reduced body weight by 1.7 +/- 0.5 kg but there was no significant change among nonfasting subjects (NF) (n = 13). Following 24 hr of fasting, PYD and DPD were lower in F (14.1 +/- 2.2 and 5.2 +/- 0.7 nmol/mmol creatinine, respectively) compared to NF (16.4 +/- 3.6 and 6.0 +/- 0.8 nmol/mmol creatinine)(p<.05). Fasting also reduce OC levels (4.8 +/- 0.4 ng/ml) compared to NF (6.1 +/- 0.9 ng/ml) (p<.01). Stepwise regression analysis of NF dietary intake indicated that energy intake explained a greater portion of the variation in bone turnover for PYD (34%), DPD (36%), and oseocalcin (46%) compared to other nutrients (p<.05). These results indicate that bone turnover is reduced by 24 hr of fasting and suggest a role for dietary energy intake in regulating bone turnover.
authors.affiliation: Department of Nutritional Sciences, 96 Lipman Dr., Rutgers University, New Brunswick, NJ 08901-8525, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Talbott
authors.forename: S A
authors.initials: SA
authors.lastname: Shapses
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000652:urine; D000704:Analysis of Variance; D001835:Body Weight; D016723:Bone Remodeling / Q000502:physiology*; D015930:Diet Records; D002149:Energy Intake; D005215:Fasting / Q000502:physiology*; D006801:Humans; D008297:Male; D009752:Nutritional Status; D015675:Osteocalcin / Q000097:blood*; D013177:Sports / Q000502:physiology*
chemical_list: D000596:Amino Acids; D015675:Osteocalcin; C015484:pyridinoline