Taken together, the results showed that the T2D‐NO group had lower abundance of A. muciniphila and baiB, decreased insulin secretion, as well as higher βCDCA, implied more transformation of CDCA into βCDCA, suggesting that the link between A. muciniphila and insulin secretion might be mediated by the βCDCA level. Here, INS is linked to type 2 diabetes mellitus.