Although this increment was only significant for FOS and one 2′-FL/probiotic combination in fermentations with stool microbiota of healthy donors, significant increases in butyrate with 2′-FL and 2′-FL/probiotic combinations were detected in ulcerative colitis donor fermentations and also with FOS and some 2′-FL/probiotic combinations in IBS donor fermentations (Figure 2). The gene discussed is FOS; the disease is ulcerative colitis.