Effect of 4 Weeks of Oral Probiotic Desulfovibrio Piger Supplementation on Immunological and Metabolic Parameters in Individuals With Longstanding Type 1 Diabetes

Inclusion Criteria: * Males or females, age \>18 years * A diagnosis of type 1 diabetes, with duration of more than 5 years, with minimally one of antiGAD65, IA2, ZnT8 autoantibodies present assessed at diagnosis or routine visits at Diabeter Centrum. * Evidence of remaining residual beta cell function with detectable UCPCR (more than 0.01 nmol/mmol C-peptide/creatinine ratio) and or fasting plasma C-peptide more than 0.2 mmol/L. * BMI 18-30 kg/m2 Exclusion Criteria: * Use of antibiotics or proton-pump inhibitors within the last three months before screening or during study period * Use of other probiotic supplementation within the last month before screening or during study period * A history of cholecystectomy * Overt untreated gastrointestinal disease, inflammatory bowel disease or abnormal bowel habits * Absence of a large bowel (ie colostomy) * Evidence for comprised immunity (HIV infection, chemotherapy, other autoimmune diseases, systemic anti-inflammatory therapy) * History of cardiovascular disaeses (CVD) events * Hepatic enzymes\>2.5 higher than the upper limit of normal range, determined during MARVEL visits/routine visits * Kidney failure (eGFR \<15ml.min/1.73m2), dialysis, kidney transplantation, * Inability or unwillingness to donate feces or urine. * Smoking or illicit drug use (e.g. MDMA/amphetamine/cocaine/heroin/GHB) in the past three months or use during the study period. * Alcohol abuse (equal or above 21 units per week) * Inability or unwillingness to provide informed consent.