Although no significant improvements in metabolic outcomes were observed in this study, the negative correlations of HbA1c levels with abundance of Bifidobacteriaceae and Peptostreptococcaceae, fasting plasma glucose (FPG) with Peptostreptococcaceae, and triglyceride (TG) with Ruminococcaceae, and the positive correlations of aspartate transaminase (AST) and alanine transaminase (ALT) with Lachnospiraceae indicate the roles of gut microbiota in metabolic homeostasis among diabetes patients. Here, GPT is linked to diabetes mellitus.