Journal Article

The Effects of a Calcium-Rich Pre-Exercise Meal on Biomarkers of Calcium Homeostasis in Competitive Female Cyclists: A Randomised Crossover Trial

Cicuttini, Flavia M., Burke, Louise M., Wluka, Anita E., Cato, Louise E., Jenkins, David G., Haakonssen, Eric C., Knight, Emma J., Wang, Bing H., Ross, Megan L., Nana, Alisa

2015

Overview

Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this. To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses. 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. 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). 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. Australian New Zealand Clinical Trials Registry ACTRN12614000675628.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adolescent / Adult / Athletes / Attenuation / Bicycling / Biomarkers / Biomarkers - blood / Blood / Body composition / Bone density / Bone growth / Bone resorption / Bone Resorption - blood / Bone Resorption - diet therapy / Bone Resorption - prevention & control / Calcium / Calcium - blood / Calcium homeostasis / Calcium, Dietary - administration & dosage / Cations, Divalent / Clinical trials / Collagen / Collagen (type I) / Collagen (type II) / Collagen Type I - blood / Collagen Type II - blood / Cross-Over Studies / Cycles / Dairy products / Diet / Energy / Enzyme-linked immunosorbent assay / Epidemiology / Exercise / Female / Health care / Homeostasis / Humans / Medical research / Nutrition / Osteogenesis / Parathyroid / Parathyroid hormone / Parathyroid Hormone - blood / Peptide Fragments - blood / Peptides - blood / Physical Endurance / Physical fitness / Physiology / Preventive medicine / Procollagen / Procollagen - blood / Proteins / Public health / Randomization / Studies / Sweat / Sweating - physiology / Vitamin deficiency / Weight control