@article{48db7d40797140d885dbc0ca0b2d0012,
title = "Urinary Hydroxyproline Is Only Suitable As a Biomarker for Acute Intake, Up to 6 hr Postingestion of Collagen Proteins in {"}Free-Living,{"} Healthy, Active Males",
abstract = "The urinary excretion of hydroxyproline (Hyp), abundant in collagen protein, may serve as a biomarker of habitual collagen intake, assisting with investigations of current interest in the role of dietary collagen intake in supporting the synthesis of collagenous body tissues. This study investigated the time course of urinary Hyp excretion in {"}free-living,{"} healthy, active males following the ingestion of a standardized bolus (20 g) of collagenous (gelatin and a hydrolyzed collagen powder) and dairy (calcium caseinate and hydrolyzed casein) proteins. The excretion of Hyp was assessed over a 24-hr period, separated into three collection periods: 0-6, 6-12, and 12-24 hr. Hyp was elevated for 0-6 hr after the consumption of collagen-containing supplements (gelatin 31.3 ± 8.8 mmol/mol and hydrolyzed collagen 33.7 ± 22.0 mmol/mol vs. baseline: gelatin 2.4 ± 1.7 mmol/mol and hydrolyzed collagen 2.8 ± 1.5 mmol/mol; p < .05), but not for the dairy protein supplements (calcium caseinate 3.4 ± 1.7 mmol/mol and hydrolyzed casein 4.0 ± 3.7 mmol/mol; p > .05). Therefore, urinary Hyp reflects an acute intake of collagenous protein, but is not suitable as a biomarker for quantifying habitual collagen intake, provided through regular dietary practices in {"}free-living,{"} healthy, active males.",
keywords = "connective tissue, gelatin, ligament, nutrition, tendon, Sports Nutritional Physiological Phenomena, Eating, Collagen/administration & dosage, Humans, Male, Cross-Over Studies, Hydroxyproline/urine, Caseins, Biomarkers/urine, Adult, Dietary Supplements",
author = "Alcock, {Rebekah D.} and Shaw, {Gregory C.} and Nicolin Tee and Marijke Welvaert and Burke, {Louise M.}",
note = "Funding Information: This study, funded by a grant administered by the Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, and provided by the ACT Brumbies Super Rugby Team, was conducted at the Australian Institute of Sport. The amino acid analysis was facilitated using infrastructure provided by the Australian government through the National Collaborative Research Infrastructure Strategy (NCRIS). R.D. Alcock, N. Tee, L.M. Burke, and G.C. Shaw were involved in the study design, results interpretation, drafting, reviewing, and revising of the manuscript. R.D. Alcock and N. Tee were involved in the data collection and data analysis, and R.D. Alcock and M. Welvaert were involved in the statistical analysis. The authors declare no conflict of interest. Publisher Copyright: {\textcopyright} 2019 Human Kinetics, Inc.",
year = "2019",
doi = "10.1123/ijsnem.2019-0024",
language = "English",
volume = "29",
pages = "461--465",
journal = "International Journal of Sport Nutrition and Exercise Metabolism",
issn = "1526-484X",
publisher = "Human Kinetics Publishers Inc.",
number = "5",
}