[Effect of the diet on the nutritional status of ballerinas: immunologic markers]

Athletes have special nutritional needs that will vary with sex, age, body composition and most importantly by the type, intensity, frequency and duration of the physical exercise. However the diet of certain groups of athletes such as ballet dancers is inadequate due to overly restrictive habits as a consequence of their obsession with losing or maintaining a low body weight that reflects an aesthetic preference for thinness. Physical exercise implies energy expenditure and thus, an increase in the energy intake is required to avoid possible situations of malnutrition. Both a negative energy balance and physical exertion have been shown to induce immunological changes which have been implicated as a possible explanation for increased susceptibility to illness and infections.

To find out the influence of a restricted energy intake on the immune system of 14 ballet dancers (20-25 h/w) in comparison with a control sedentary group (n = 23) by evaluating dietetic, anthropometric and some immunological parameters.

Ballet dancers consumed a hypocaloric diet (mean: 1555 kcal), the energy intake being significantly lower than in the control group. None of both groups showed a similar calorie profile to the recommended intake for Spanish population, especially fat percentage was higher than it should. Regarding weight, ideal body weight and BMI values, no significant differences were shown between both groups. However, all the skinfolds thickness and the sum of skinfolds were significantly lower in ballet dancers than in controls. Leukocytes, lymphocytes and all lymphocyte subset counts were lower in ballet dancers in comparison with controls.

In view of these results, ballet dancers may suffer from an impaired nutritional status, determined by a depletion of anthropometric and immunological parameters. The nutritional requirements for this population should be increased in order to compensate their high-energy expenditure, avoid a negative energy balance and lessen the nutritional damage.