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PLoS One. 2015 May 13;10(5):e0123302. doi: 10.1371/journal.pone.0123302. eCollection 2015.

The effects of a calcium-rich pre-exercise meal on biomarkers of calcium homeostasis in competitive female cyclists: a randomised crossover trial.

Author information

1
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia; Physiology, Australian Institute of Sport, Belconnen, 2616, Australia; Human Movement Studies, University of Queensland, St Lucia, 4072, Australia.
2
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia; Physiology, Australian Institute of Sport, Belconnen, 2616, Australia.
3
Performance Research, Australian Institute of Sport, Belconnen, 2616, Australia.
4
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia.
5
Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Melbourne, 3004, Australia.
6
Human Movement Studies, University of Queensland, St Lucia, 4072, Australia.
7
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia; School of Exercise Science, Australian Catholic University, Melbourne, 3065, Australia.

Abstract

Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this.

PURPOSE:

To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses.

METHODS:

Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique.

RESULTS:

PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819).

CONCLUSION:

This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption--PTH and CTX-I.

TRIAL REGISTRATION:

Australian New Zealand Clinical Trials Registry ACTRN12614000675628.

PMID:
25970439
PMCID:
PMC4430171
DOI:
10.1371/journal.pone.0123302
[Indexed for MEDLINE]
Free PMC Article

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