Currently, it is well accepted that nutrition is an important factor for the development of the immune response. Epidemiological and clinical results suggest that any nutritional deficiency alters immunocompetence and increases the susceptibility to infections(Reference Gleeson, Nieman and Pedersen^1, Reference Moreira, Kekkonen, Delgado, Fonseca, Korpela and Haahtela²). thus, the purpose of the present study was to compare the nutritional status of ten young male elite track and field athletes (20–48 h training/week) aged 13–18 years at a baseline state (48 h relaxation after training) with a control group consisting of ten volunteer students, matched by age and socio-economic status, who were doing<8 h physical exercise/week. Nutritional status was assessed by dietary intake for 3 d, anthropometry (BMI and triceps skinfold thickness) and immunocompetence (total counts of leucocytes, lymphocytes and lymphocyte subsets (CD3, CD4, CD8, CD19 and CD16+56)).

The energy intake was similar for athletes and controls (8327 v. 8235 kJ/d respectively), and lower than that recommended by the Food and Nutrition Board, Institute of Medicine(³), the American Dietetic Association(⁴)and the American Academy of Pediatrics(⁵). BMI and triceps skinfold thickness were significantly lower for the athletes than for the controls. Total leucocyte and total lymphocyte counts were similar for both groups. However, a decrease in CD3, CD8, CD19 and CD16+56 lymphocyte subset counts was found for athletes in comparison with controls.

NK, natural killer. Mean values were significantly different from those of the controls (Student's t test): *P<0.05.

These results suggest that the young athletes assessed in the current study could show subclinical malnutrition, with a leaner body and an impaired immunocompetence compared with the control group, although the dietary intake was similar for both groups but below recommendations. A higher-energy diet should be recommended for these high-performance athletes in order to avoid further risk of malnutrition and to avoid more serious complications, such as infections.