Randomized, placebo-controlled dose-ranging study of 2'-FL in IBD, Crohn's Disease (CD) and ulcerative colitis (UC). The overarching hypothesis is that 2'-FL supplementation in IBD will be safe and well tolerated, while increasing fecal Bifidobacterium abundance and butyrate in a dose dependent manner. The investigators will test 1, 5, or 10 gm 2'-FL compared to 2 gm dextrose placebo as a daily dietary supplement in pediatric and young adult IBD participants in stable remission receiving infliximab, adalimumab, or infliximab-dyyb biosimilar anti-TNF therapy.