Three subjects with DM were on nutrition therapy and 3 patients were taking oral anti-diabetic drugs (2 subjects on metformin monotherapy and one subject on metformin and dipeptidyl peptidase IV inhibitor therapy) at a stable dose for at least 6 months and no one was treated with either insulin or glucagon-like peptide 1 receptor agonist (GLP1-RA) or sodium-glucose cotransporter-2 inhibitor (SGLT2-i). Here, DPP4 is linked to diabetes mellitus.