Effects of energy availability and dietary macronutrients on bone mineral density in male and female vocational ballet dancers

INTRODUCTION: Adequate Energy Availability (EA) is crucial to support physiological functions, optimal performance and bone mineral density (BMD). Young ballet dancers following a high-volume of training are predisposed to low EA due to high Energy Expenditure (EE) and insufficient Energy Intake (EI) to match this balance. This study aimed to examine the relationship between EA, dietary macronutrients and BMD in vocational ballet dancers. METHODS: BMD and body composition of 25 dancers (female n=15, male n=10) were measured via DEXA. Three-day EA was calculated by subtracting EE (measured using continuous heart rate monitoring – Polar M430) from EI (dietary diary). Macronutrients (Carbohydrates, Protein, Fat) were analysed using Nutritics Software. Menstrual status was evaluated through questionnaires. RESULTS: Low EA (<30kcal/kgFFM/day) was found in 88% of ballet dancers (12 female, 10 male) (3.9±22.7 kcal/FFM/ day). There were significant differences between female and male in lumbar spine (LS) BMD Z-score (female -1.1±0.7; male 0.29±0.7), EA (female 15.7±31.0 kcal/FFM/ day; male -13.7±11.3 kcal/FFM/ day) and EE (female 1386±540.6 kcal; male 3026±279.4 kcal). There was moderate-negative correlation between EA and BMD Z-score LS (r=-0.581; p=0.002) and strong-positive correlation between EE and BMD Z-score LS (r=0.727; p