Author(s): ESTEVES, G., DUMAS, A., TAKARABE, L., PERFEITO, L., KEANE, K., GUALANO, B., KELLEY, G., BURKE, L., SALE, C., SWINTON, P., DOLAN, E., Institution: FACULTY OF MEDICINE, UNIVERSITY OF SÃO PAULO (FMUSP), Country: BRAZIL, Abstract-ID: 1343

INTRODUCTION:
Although nutrition and exercise both influence bone metabolism, little is currently known about their interaction. Synthesis of available information has substantial potential to inform nutritional interventions to protect the bone health of exercising individuals, including athletes with high risk of compromised bone health. The purpose of this study was to synthesise available evidence related to the influence of nutrition on the bone biomarker response to acute exercise, using a systematic review and meta-analytic approach.
METHODS:
Studies evaluating the influence of nutritional status or intervention on the acute bone biomarker response to a single bout of exercise were included and separated into 4 categories: A) Feeding status and energy availability; B) Macronutrients; C) Micronutrients, and D) Other. Studies conducted on healthy human populations of any age or training status were included. Meta-analysis was conducted when data from at least 5 studies with independent datasets were available, and results are presented as standardized effect sizes and 95% credible intervals (95%CrI). In the case of insufficient data for specific outcomes, results from individual studies were narratively synthesised and standardised mean effect sizes visually represented.
RESULTS:
Twenty-three articles were included. Of these, 4 investigated feeding status or energy availability; 7 macronutrients; 8 micronutrients (all calcium) and 6 investigated other approaches, namely, collagen, dairy products or ubiquinol. The largest and most commonly reported effects of a nutritional intervention on the bone biomarker response to exercise were for the bone resorption marker CTX-1. Calcium intake, whether provided via supplements, diet or infusion, reduced exercise-induced increases in CTX-1 (-1.1 [95%CrI: -2.2 to -0.05]). Excluding studies that used calcium infusion reduced the magnitude of this effect (-0.47 [95%CrI: -0.95 to 0.02]). Carbohydrate supplementation appears to support bone during acute exercise, via reducing exercise-induced increases in CTX-1 and potentially increasing the P1NP response. Conversely, a low-carbohydrate/high-fat diet induced the opposite effect. Low energy availability may amplify the CTX-1 response to exercise, but it is unclear whether this is directly attributable to energy availability, or to the lack of specific nutrients, such as carbohydrate.
CONCLUSION:
Nutritional intervention can modulate the acute bone biomarker response to exercise, primarily through influencing bone catabolism. In turn, ensuring adequate attention to nutritional factors may be important to protect bone health of exercising individuals, with energy, carbohydrate and calcium availability particularly important factors to consider. Although a wide breadth of data were available, there was substantial heterogeneity in relation to design and intervention characteristics. Direct and indirect replication is required to confirm key findings and to generate better estimates of true effect sizes.