Bile acids (BAs), on the other hand, participate in the maintenance of human health and the development of metabolic diseases as signaling molecules activating receptors in the gut, liver, and adipose tissue (138), majorly under the modulation of the nuclear Farnesoid X receptor (FXR) and its downstream targets fibroblast growth factor (FGF) 15/19 in intestines and small heterodimer partner in liver (139). This evidence concerns the gene NR1H4 and metabolic disease.