Food hypersensitivity is recognized as a rather common condition, that can occur at any age. There is limited high-quality data on the burden of this condition, especially after child age. The aim of this thesis has been to explore whether levels of biomarkers in blood differ between adolescents with self-reported hypersensitivity against certain food and the control group in a general youth population. This project is based on data from the Tromsø Study Fit Futures 2. The study population includes 376 females and 307 males (age 17-21) in upper secondary school from the neighbouring municipalities Tromsø and Balsfjord, North Norway. Data on self-hypersensitivity against foods was assessed by a web-based questionnaire and levels of Hb, Fe, Ferritin, Calcium and Vitamin D were measured. There was a statistically significant difference between mean Hb-levels in participants with any kind of food reaction (p < 0.05), and food reactions to wheat (p < 0.001), nuts (p < 0.05) and peanuts (p < 0.001) compared to participants with no food reactions; the subjects with food reactions having a lower mean value. Amongst adolescents with a reported food reaction to wheat, there were also a statistically significant lower level of Ferritin and Calcium values (all p < 0.05). Aside from these there were no significant differences in mean/median biomarker values for Hb, Fe, Ferritin, Calcium or Vitamin D when comparing subjects with and without self-reported food reactions. Self-reported reaction to wheat was also associated with having Calcium levels below reference level (p < 0.05). Except for this, there were no associations between having a food reaction and having biomarker levels below reference levels or in the lower quartile. This study suggests that there is a slight difference in biomarker levels when comparing a youth population with self-reported food reactions to a control group, especially in subjects reporting wheat hypersensitivity. More detailed research is needed on this subject to conclude with how and to which extent this affects the nutritional status of these adolescents
