Two of these, FGF-21 and FGF-19, have clear roles associated with diet, with FGF-19 regulating bile acid homeostasis and FGF-21 regulating energy homeostasis.24 Research from the 1000IBD project has previously highlighted FGF-19 to differentially associate with different dietary patterns independent of IBD type and disease activity.36 A clear link such as this within patients with IBD between diet and the other 3 IRPs is yet to be proposed; however, indications are present within the literature. Here, FGF21 is linked to inflammatory bowel disease.