The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and Diabetes

Inclusion criteria Subgroup 1: * Age 18 or older * HbA1c below 6.5% * Written informed consent Subgroup 2: * Age 18 or older * T1D (Type 1 diabetes) with MDI (multiple daily injection) or CSII (Continuous subcutaneous insulin infusion therapy) therapy \>1 year * Written informed consent Subgroup 3 * Age 18 or older * T2D (Type 2 diabetes) with oral antidiabetic medication or insulin therapy * Written informed consent Exclusion criteria * Pregnancy or breastfeeding * Smoking (last cigarette less than 6 months ago) * Any chronical lung and intestinal disease diagnosis (such as intestinal bowel disease (IBD); asthma; COPD (chronic obstructive pulmonary disease); lung cancer, …) * Coeliac disease * Lactose and fructose intolerance * Any acute disease diagnosis (such as viral or bacterial infection) * Drinking habit of more than four units of alcohol per day * Current inhaled medicines treatments * Antibiotic treatment in the previous 4 months