Strenght from within...Bones

By Nicolette Braybrook LISTD (Dip) BSc (Chem) Mast. Nut. & Diet.

Bone Health is often neglected by the dancer, which in turn can compromise their health and longevity of fitness. This may occur through a lack of nutritional education, or a deliberate avoidance of food groups that are perceived to be high in fat.

Bone is a living tissue where calcium is stored. The strength of bone present in a young dancer is determined by genetic make up, gender, the amount of weight bearing activity or exercise, hormonal determinants and also nutritional intake. (especially calcium)

During adolescence, dancers build their calcium 'stores' and bone strength, but this can only occur when their diet is nutritionally balanced and they are in good health. At around 20 years of age, bones have generally reached their peak strength and at about 35 years of age, bones slowly start to lose calcium at up to 1% each year, except for during menopause, where the loss of calcium is at a faster rate.

Weight bearing activities, such as dance, have a positive effect on increasing or maintaining peak bone mass. If peak bone mass decreases, a fracture threshold may be reached and bones may be more vulnerable to breakage. This is particularly important to the dancer, whom over their career, may find themselves with recurrent stress fractures.

Whilst an adequate intake of calcium is important for all dancers, females who are amenorrhoeic may require up to twice as much calcium daily. Various explanations have been proposed for amenorrhoea amongst dancers and these include body composition (ie. low body fat percentage), training intensity and diet. (Note: amenorrhoea is usually defined as the absence of a menstrual period for 3-6 months)

Dancers that are amenorrhoeic have lower levels of circulating oestrogen, which can then lead to loss of bone strength and possibly stress fractures. This similar hormonal effect can also be seen in menopausal women. The use of the oral contraceptive pill for dancers whom are amenorrhoeic may offer some protection against stress fractures. This is yet to be proven scientifically, but studies in this area are ongoing.

Recommended Daily Intake of Calcium (Australia)

The best source of calcium within the diet are dairy products. The calcium found in these foods are more easily absorbed by the body than other calcium containing foods. As a guide, the following foods contain approximately 300mg of calcium:-

• 35g cheddar cheese
• 250ml milk
• 200g yoghurt
• 135g ricotta cheese
• 100g sardines or salmon (with bones)

In some cases, female dancers believe or actually need to limit their fat intake in order to obtain or maintain a lean body shape. The myths and perceptions that all dairy products are high in fat is totally inaccurate. There is an extensive range of low fat dairy options currently on the market and dancers should include these daily in their diet.

To conclude, all dancers should be aware of the consequences, even if they are long term, of limiting their calcium intake. Nutritional education is vital, especially for adolescent dancers, who are building their peak bone mass. With the extensive range of low fat dairy products available today, there is no excuse for dancers not to include these in their daily intake. If you have any further queries, please consult a Sports Dietitian.

Nicolette Aisen is a Sports Dietitian and specialises in the dance field, specifically to the adolescent dancer. She has been teaching a variety of dance for over 15 years and is the Director of a dance school in the North West of Melbourne. She can be contacted on
+ 61 3 97469823 or nicobret@mail.austasia.net