Onset of Ulcerative Colitis in a Patient with Type 2 Diabetes: Efficacy of a Plant-Based Diet for Both Diseases

No case has been reported in which ulcerative colitis occurred in a patient with type 2 diabetes mellitus and the patient was treated with a plant-based diet. A 56-year-old man with a 3-year history of diabetes noticed bloody stool about 2 months after his worst glycated hemoglobin A1c test. Endoscopy revealed diffuse inflammation in the rectum. He was diagnosed with ulcerative colitis (proctitis, mild severity). He underwent educational hospitalization. A plant-based diet (1400 kcal/day) was provided. The same dosage of metformin was continued, but no medication was prescribed for ulcerative colitis. At the end of hospitalization, fecal occult blood 271 ng/mL became negative. Glycated hemoglobin A1c 6.9% had decreased to 6.6%. Two months after discharge, glycated hemoglobin A1c decreased to normal for the first time in 3.5 years. Ulcerative colitis had been in remission without medication for one and a half years after the educational hospitalization. Thereafter, however, he experienced two flareups. Deterioration in glycated hemoglobin A1c preceded the flareups. We described a scarcely reported case in which ulcerative colitis occurred in a patient with diabetes and the patient was treated with a plant-based diet. The plant-based diet was effective for both diseases. It seemed that the status of diabetes influenced the onset and relapse of ulcerative colitis.