@article{cd61f5c249cc4aa0a8e1c85ec7ad03c6,
title = "Influence of periodizing dietary carbohydrate on iron regulation and immune function in elite triathletes",
abstract = "Sleeping with low carbohydrate (CHO) availability is a dietary strategy that may enhance training adaptation. However, the impact on an athlete{\textquoteright}s health is unclear. This study quantified the effect of a short-term “sleep-low” dietary intervention on markers of iron regulation and immune function in athletes. In a randomized, repeated-measures design, 11 elite triathletes completed two 4-day mixed cycle run training blocks. Key training sessions were structured such that a high-intensity training session was performed in the field on the afternoon of Days 1 and 3, and a low-intensity training (LIT) session was performed on the following morning in the laboratory (Days 2 and 4). The ingestion of CHO was either divided evenly across the day (HIGH) or restricted between the high-intensity training and LIT sessions, so that the LIT session was performed with low CHO availability (LOW). Venous blood and saliva samples were collected prior to and following each LIT session and analyzed for interleukin-6, hepcidin 25, and salivary immunoglobulin-A. Concentrations of interleukin-6 increased acutely after exercise (p < .001), but did not differ between dietary conditions or days. Hepcidin 25 increased 3-hr postexercise (p < .001), with the greatest increase evident after the LOW trial on Day 2 (2.5 ± 0.9 fold increase ±90% confidence limit). The salivary immunoglobulin-A secretion rate did not change in response to exercise; however, it was highest during the LOW condition on Day 4 (p = .046). There appears to be minimal impact to markers of immune function and iron regulation when acute exposure to low CHO availability is undertaken with expert nutrition and coaching input.",
keywords = "Hepcidin, Sleep low, Train low",
author = "McKay, {Alannah K.A.} and Heikura, {Ida A.} and Burke, {Louise M.} and Peter Peeling and Pyne, {David B.} and {van Swelm}, {Rachel P.L.} and Laarakkers, {Coby M.} and Cox, {Gregory R.}",
note = "Funding Information: The support and assistance of the Australian Institute of Sports Nutrition and Physiology staff, and Samantha Leyh, Emily Fallon, and Shannon Connolly during the data collection are gratefully acknowledged. The authors thank the athletes involved in this study for their commitment and dedication to the training camp. Importantly, this study would not have been possible without the support and willingness of Jamie Turner, Coach of Triathlon Australia?s International Performance Centre. This study was financially supported by grants from the Australian Catholic University Research Fund, Australian Institute of Sport?s High Performance Sport Research Fund, and Triathlon Australia. The study was designed by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox; the data were collected and analyzed by A.K.A. McKay, I.A. Heikura, L.M. Burke, R.P.L. van Swelm, C.M. Laarakkers, and G.R. Cox. The data interpretation and manuscript preparation were undertaken by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox. All of the authors approved the final version of the article. Funding Information: The support and assistance of the Australian Institute of Sports Nutrition and Physiology staff, and Samantha Leyh, Emily Fallon, and Shannon Connolly during the data collection are gratefully acknowledged. The authors thank the athletes involved in this study for their commitment and dedication to the training camp. Importantly, this study would not have been possible without the support and willingness of Jamie Turner, Coach of Triathlon Australia{\textquoteright}s International Performance Centre. This study was financially supported by grants from the Australian Catholic University Research Fund, Australian Institute of Sport{\textquoteright}s High Performance Sport Research Fund, and Triathlon Australia. The study was designed by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox; the data were collected and analyzed by A.K.A. McKay, I.A. Heikura, L.M. Burke, R.P.L. van Swelm, C.M. Laarakkers, and G.R. Cox. The data interpretation and manuscript preparation were undertaken by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox. All of the authors approved the final version of the article. Publisher Copyright: {\textcopyright} 2020 Human Kinetics, Inc. Copyright: Copyright 2020 Elsevier B.V., All rights reserved. Funding Information: The support and assistance of the Australian Institute of Sports Nutrition and Physiology staff, and Samantha Leyh, Emily Fallon, and Shannon Connolly during the data collection are gratefully acknowledged. The authors thank the athletes involved in this study for their commitment and dedication to the training camp. Importantly, this study would not have been possible without the support and willingness of Jamie Turner, Coach of Triathlon Australia{\textquoteright}s International Performance Centre. This study was financially supported by grants from the Australian Catholic University Research Fund, Australian Institute of Sport{\textquoteright}s High Performance Sport Research Fund, and Triathlon Australia. The study was designed by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox; the data were collected and analyzed by A.K.A. McKay, I.A. Heikura, L.M. Burke, R.P.L. van Swelm, C.M. Laarakkers, and G.R. Cox. The data interpretation and manuscript preparation were undertaken by A.K.A. McKay, I.A. Heikura, L.M. Burke, P. Peeling, D.B. Pyne, and G.R. Cox. All of the authors approved the final version of the article. Publisher Copyright: {\textcopyright} 2020 Human Kinetics, Inc.",
year = "2020",
month = jan,
day = "1",
doi = "10.1123/ijsnem.2019-0131",
language = "English",
volume = "30",
pages = "34--41",
journal = "International Journal of Sport Nutrition and Exercise Metabolism",
issn = "1526-484X",
publisher = "Human Kinetics Publishers Inc.",
number = "1",
}