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Chronic Adherence to a Ketogenic Diet Modifies Iron Metabolism in Elite Athletes

MCKAY, ALANNAH K. A.1,2,3; PEELING, PETER1,3; PYNE, DAVID B.2,4; WELVAERT, MARIJKE2,4; TEE, NICOLIN2; LECKEY, JILL J.5; SHARMA, AVISH P.2,4; ROSS, MEGAN L. R.2,5; GARVICAN-LEWIS, LAURA A.2,5; SWINKELS, DORINE W.6,7; LAARAKKERS, COBY M.6,7; BURKE, LOUISE M.2,5

Medicine & Science in Sports & Exercise: March 2019 - Volume 51 - Issue 3 - p 548–555
doi: 10.1249/MSS.0000000000001816
APPLIED SCIENCES
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Purpose The short-term restriction of carbohydrate (CHO) can potentially influence iron regulation via modification of postexercise interleukin-6 (IL-6) and hepcidin levels. This study examined the effect of a chronic ketogenic low-CHO high-fat (LCHF) diet on iron status and iron-regulatory markers in elite athletes.

Methods International-level race walkers (n = 50) were allocated to one of three dietary interventions: (i) a high-CHO diet (n = 16), (ii) a periodized CHO availability (n = 17), or (iii) an LCHF diet (n = 17) while completing a periodized training program for 3 wk. A 19- to 25-km race walking test protocol was completed at baseline and after adaptation, and changes in serum ferritin, IL-6, and hepcidin concentrations were measured. Results from high-CHO and periodized CHO were combined into one group (CHO; n = 33) for analysis.

Results The decrease in serum ferritin across the intervention period was substantially greater in the CHO group (37%) compared with the LCHF (23%) group (P = 0.021). After dietary intervention, the postexercise increase in IL-6 was greater in LCHF (13.6-fold increase; 95% confidence interval [CI] = 7.1–21.4) than athletes adhering to a CHO-rich diet (7.6-fold increase; 95% CI = 5.5–10.2; P = 0.033). Although no significant differences occurred between diets, CI values indicate that 3 h postexercise hepcidin concentrations were lower after dietary intervention compared with baseline in CHO (β = −4.3; 95% CI = −6.6 to −2.0), with no differences evident in LCHF.

Conclusion Athletes who adhered to a CHO-rich diet experienced favorable changes to the postexercise IL-6 and hepcidin response, relative to the LCHF group. Lower serum ferritin after 3 wk of additional dietary CHO might reflect a larger more adaptive hematological response to training.

1School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, WA, AUSTRALIA;

2Australian Institute of Sport, Bruce, ACT, AUSTRALIA;

3Western Australian Institute of Sport, Mt Claremont, WA, AUSTRALIA;

4Research Institute for Sport and Exercise, University of Canberra, Canberra, AUSTRALIA;

5Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, AUSTRALIA;

6Department of Laboratory Medicine (TML 830), Radboud University Medical Center, Nijmegen, THE NETHERLANDS; and

7Hepcidinanalysis.com, Nijmegen, THE NETHERLANDS

Address for correspondence: David Pyne, Ph.D., F.A.C.S.M., Research Institute for Sport and Exercise, University of Canberra, Canberra 2601, Australia; E-mail: david.pyne@canberra.edu.au.

Submitted for publication August 2018.

Accepted for publication October 2018.

© 2019 American College of Sports Medicine