To build up sufficient knowledge of a ‘healthy diet’. Here, we report on the assessment of nutritional knowledge using a uniform method in a large sample of adolescents across Europe.

A cross-sectional study.

The European multicentre HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study conducted in 2006–2007 in ten cities in Austria, Belgium, France, Germany, Greece (one inland and one island city), Hungary, Italy, Spain and Sweden.

A total of 3546 adolescents (aged 12·5–17·5 years) completed a validated nutritional knowledge test (NKT). Socio-economic variables and anthropometric data were considered as potential confounders.

NKT scores increased with age and girls had higher scores compared with boys (62 % v. 59 %; P < 0·0001). Scores were approximately 10 % lower in ‘immigrant’ adolescents or in adolescents with ‘immigrant’ mothers. Misconceptions with respect to the sugar content in food or in beverages were found. Overall, there was no correlation between BMI values and NKT scores. After categorization according to BMI, scores increased significantly with BMI group only in boys. These differences disappeared after controlling for socio-economic status (SES). Smoking status and educational level of the mother influenced the NKT scores significantly in boys, as well as the educational levels of both parents in girls.

Nutritional knowledge was modest in our sample. Interventions should be focused on the lower SES segments of the population. They should be initiated at a younger age and should be combined with environmental prevention (e.g. healthy meals in school canteens).