Background: An adequate nutritional status of antioxidant vitamins (vitamins A, C, E) and b-carotene is essential especially during childhood and adolescence, because of their important roles in cell growth and development. Currently, there are no physiological reference values for blood concentration of these vitamins and b-carotene in apparently healthy European adolescents. The aim of the current study was to obtain reliable and comparable data of antioxidant vitamins and b-carotene in a cross-sectional study, within HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence), which was conducted in a representative sample of adolescents from ten European cities.
Material and methods: From a subsample of 1,054 adolescents (males= 501) of the HELENA Cross Sectional Study with an age range of 12.5 to 17.49 years, fasting blood samples were taken and analyzed for vitamins A, E, C, and b-carotene status. As specific reference values for adolescents are missing, percentile distribution by age and sex is given.
Results: Mean concentrations were the following: Retinol: 356.4 ± 107.9 cm/mL; alpha-tocopherol: 9.9 ± 2.1 microg/mL; vitamin C: 10.3 ± 3.3 mg/L; and b-carotene: 245.6 ± 169.6 cm/mL. Females showed higher alpha-tocopherol and vitamin C values compared with males and 17-year-old boys had higher retinol levels than the same-aged girls (p = 0.018). Retinol serum concentrations increased significantly according to age in both gender, but girls had also significantly increasing b-carotene levels by age.
Conclusions: For the first time, concentrations of antioxidant vitamins and pro-vitamin beta-carotene have been obtained in a representative sample of apparently healthy European adolescents. These data can contribute to the establishment of reference ranges in adolescents.