Effect of Protein Supplementation on Body Composition and Dance Performance in Female Collegiate Dancers

Background: Female aesthetic athletes strive to attain an ideal body image for their sports. Dancers in particular pose an addition issue in that they are performing artists and are often not considered athletes. The physical demands placed on dancers from choreography and performance schedules make their body composition, physiology and optimal fitness just as important as their technique development. Body composition, specifically fat mass (FM) and lean mass (LM), has shown positive changes in response to increased protein intake in lean populations (119, 200). A diet higher in protein may be a simple way to optimize body composition and dance performance without dramatically changing or adding to classical dance training. Improvements in body composition from supplemental protein alone may improve aesthetics of dance performance. To date, no studies have investigated the impact of increased protein intake on body composition and performance in a dance population. Purpose: To determine the extent to which supplemental whey protein (PRO) consumed three times daily (75g total/day) for 12 weeks will optimize body composition and dance performance in female collegiate dancers when compared to an isocaloric placebo (PLA). Methods: Twenty-one (19.6 ± 1.4 years) female collegiate dancers from Florida State University’s School of Dance completed this randomized, double-blind, placebo controlled study. Participants were randomly assigned a PLA or PRO supplement (25g, 3x/day) and were instructed to consume one scoop (25g protein) with water between major meals of breakfast, lunch, and dinner. Following familiarization, participants completed laboratory testing at baseline, mid, and post-testing of the 12-week intervention. Laboratory testing included, 24-hour urine collection, body composition assessment (dual x-ray absorptiometry; DXA), resting metabolic rate (indirect calorimetry), venous blood draw, whole body circumferences scan, performance tests, and a functional dance performance assessment. Additionally, participants completed weekly 3-day food logs and satiety questionnaires to assess dietary changes throughout the study. Data were reported as mean ± SD. Dependent variables were analyzed by two-way (group x time) analysis of variance (ANOVA). Post hoc test were used to compare group or time differences. Significance was accepted at p<0.05. Results: There were no significant differences in participant demographics, body composition, or diet at baseline. PLA consumed significantly lower protein (g/kg/day) than PRO every week of the study (p<0.001). Body weight, FM, and LM did not change between groups or over time. LM (%) at post-testing trended toward significance between PLA and PRO (+0.5 ± 3.0%, -2.7 ± 5.2%, respectively; p=0.057). Lean mass index (LMI= (LMpost-LMpre)+(FMpre-FMpost)) was significantly lower in PLA (-1.8 ± 3.1) compared to PRO (+0.6 ± 1.9; p=0.048) at post-testing. PLA achieved a higher hamstrings-to-quadriceps ratio at mid (63.4 ± 9.2% vs. 54.7 ± 7.8%; p=0.031) compared to PRO and significantly increased absolute (746.4 ± 92.9 W, 856.3 ± 51.6 W; p=0.005) and relative (12.7 ± 1.4 W, 14.6 ± 1.4 W; p=0.004) peak power during the Wingate anaerobic power test from baseline to post-testing. Although not significant, PLA completed the study in negative nitrogen balance whereas PRO was in positive nitrogen balance. Differences detected in aesthetic presentation from baseline to post-testing were significantly lower in PLA (1.9 ± 0.5, on a 1.0-5.0 scale) compared to PRO (2.6 ± 0.8, on a 1.0 to 5.0 scale; p=0.048). Conclusion: Protein supplementation for 12 weeks was well tolerated and significantly improved LMI as well as aesthetic presentation during dance performance. Although overall body composition was more optimal in PRO, individual measures (FM and LM) were not significantly different between groups. PRO supplementation did not significantly impact laboratory testing. Protein supplementation has no adverse side effects on a dance population and improves LMI and aesthetics in dance performance. In addition, protein supplementation provides a simple way to improve the diet as well as LMI in a group of dance athletes that need more nutritional attention.