Total food and beverage consumption will be assessed by means of a 7 days long questionnaire. All participants will be trained by a nutritionist to record all food consumed and the completed forms will be returned and reviewed during a face-to-face interview at which portions size were quantified in standard units. Participants will be asked to weigh all foods and drinks consumed and to provide a detailed description of each food, including methods of preparation and recipes, whenever possible. In case of Gluten Free Foods, patients will be asked to precisely note the name of the manufacturer or to provide the food label.