Professional ballerinas have a high incidence of vitamin D deficiency, improving slightly during summer months. Dancers also are more likely to get injured during the winter, according to research published in the Journal of Science and Medicine in Sport.
Roger Wolman, MD, of the Royal National Orthopaedic Hospital in Stanmore, UK, and colleagues recruited 18 ballet dancers from a single international touring dance company. The participants were professional Caucasian dancers who dance an average of 6-8 hours per day, 38 hours per week. A lifestyle questionnaire and blood samples were completed in February and August 2010. Company doctors kept track of any injuries that occurred during the study period.
Dr Wolman and colleagues found that during winter season, all dancers were either insufficient, characterized as 10-30 ng/ml, or deficient, <10 ng/ml. During summer months the authors noted significant improvement, with 3 dancers with vitamin D levels >30 ng/ml, while 14 were insufficient and 2 deficient. The authors also found that serum parathyroid hormone (PTH) significantly decreased during this time. Chronically high PTH is associated with vitamin D deficiency and can lead to problems with the thyroid.
There was a significant decrease in incidence of injury between winter and summer months (p<0.05). Interestingly, the authors noticed that among female dancers, taking an oral contraceptive had a significant beneficial effect on vitamin D status, PTH, and markers of healthy bone. They conclude,
“Further studies on the impact of vitamin D3 supplementation on markers of bone metabolism, muscle function and injury profile would help to enhance our understanding of this important area of metabolism in athletes/dancers.”