title: Urinary levels of cross-linked N-terminal telopeptide of type I collagen and nutritional status in Japanese professional baseball players.
abstract: The objective of the present study was to investigate the nutritional status from the aspect of bone metabolism in Japanese elite male athletes with increased bone resorption. Urinary levels of a bone resorption marker, cross-linked N-terminal telopeptide of type 1 collagen (NTX), were measured in 71 professional baseball players (age, 18-39 years); the mean urinary NTX level was 65.6 (range, 17.5-269.0) nM BCE/mM Cr. Of 71 athletes, 9 with high levels of urinary NTX (greater than mean + 1 SD) were examined by measuring serum biochemical markers and nutritional assessment (simple food frequency questionnaire). Serum biochemical marker analysis showed that 7 of these 9 athletes had vitamin D insufficiency, as indicated by low serum levels of 25-hydroxyvitamin D, and that all 9 athletes showed vitamin K insufficiency as indicated by low levels of vitamins K(1) and K(2). Nutritional assessment revealed high intakes of protein and low intakes of calcium and vitamin D based on adequate intake (AI). However, daily vitamin K intake achieved the AI. These results suggest that there exist elite male athletes who show increased bone resorption and calcium and vitamin D insufficiency. However, there was a discrepancy between vitamin K intake and serum levels of vitamins K(1) and K(2). The present study raised an issue regarding the nutritional status from the point of view of bone metabolism in elite male athletes such as professional baseball players.
authors.affiliation: Institute for Integrated Sports Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. jiwamoto@sc.itc.keio.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Iwamoto
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takeda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Uenishi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ishida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sato
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D001484:Baseball; D015415:Biomarkers / Q000652:urine*; D001862:Bone Resorption / Q000652:urine; D001842:Bone and Bones / Q000378:metabolism*; D002136:Calcium, Dietary / Q000378:metabolism; D024042:Collagen Type I / Q000652:urine*; D006801:Humans; D007564:Japan; D008297:Male; D009752:Nutritional Status; D010455:Peptides / Q000652:urine*; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood; D010837:Vitamin K 1 / Q000097:blood; D024482:Vitamin K 2 / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D024482:Vitamin K 2; D014807:Vitamin D; D010837:Vitamin K 1