Nicotinamide Riboside in Ulcerative Colitis

This trial is testing whether a supplement called nicotinamide riboside (a form of vitamin B3) can help children with ulcerative colitis (UC) — a form of inflammatory bowel disease that causes chronic inflammation in the large intestine. Researchers hope it may reduce inflammation and ease symptoms in younger patients. **You may be eligible if...** - Your child is 18 years old or younger - Your child has been diagnosed with mild to moderate ulcerative colitis confirmed by colonoscopy - Both newly diagnosed children and those with established disease may enroll **You may NOT be eligible if...** - Your child has severe ulcerative colitis (a medical emergency) - Your child has an active gut infection (such as C. difficile or CMV) - Your child has Crohn's disease or indeterminate colitis - Your child has received steroids or antibiotics in the past 3 months (unless on a stable biologic for at least 3 months) - Your child has another chronic inflammatory or autoimmune disorder, or a prior cancer - Your child is pregnant - Your child has kidney or liver problems - Your child's platelet count is below 50,000 Talk to your doctor to see if this trial is right for you.