The Lactobreath project uses the breath we exhale to find markers for lactose intolerance as a model for food intolerance diagnosis. We aim to identify breath markers for lactose tolerance and link them to metabolic traits. We use a real-time breath analysis method and a special sensor to measure gases in the digestive system. We also explore lactose metabolism with urinary biomarkers and genetic factors using saliva samples. The study is conducted at ETHZ in collaboration with Agroscope. Urine metabolomics, dietary assessment and microbiota analyses are supervised by researchers at Agroscope. This project aims to develop non-invasive breath tests to help food intolerance diagnosis and management. It will also advance the wider use of breath analysis for personalized nutrition.