Introduction: The increasing prevalence of diabetes mellitus (DM) has intensified research into its mechanisms and complications. Alterations in gut microbiota are considered an environmental factor influencing the onset, progression, and complications of diabetes. This review summarizes current evidence on the role of microbiota in diabetes and its outcomes. Methods: This literature review was conducted using English-language articles from PubMed and Google Scholar, focusing on original research and reviews, primarily published within the last 10 years. Key search terms included “type 1 diabetes mellitus,” “type 2 diabetes mellitus,” “gut microbiota dysbiosis,” and related metabolic and complication terms. Both animal and human studies were included. Results: Current studies reveal a strong correlation between gut microbiota alterations and diabetes and its complications. Dysbiosis, characterized by reduced bacterial diversity, is observed in both type 1 (T1DM) and type 2 diabetes (T2DM) patients. In T1DM, dysbiosis may contribute to immune dysregulation and increased intestinal permeability. In T2DM, lower bacterial diversity is linked to insulin resistance and obesity. Dysbiosis is also directly associated with diabetic retinopathy and contributes to nephropathy, neuropathy, and ischemic heart disease. Discussion: These findings suggest that gut microbiota alterations may play a role in diabetes pathogenesis and its complications, indicating potential targets for therapeutic modulation. However, causal relationships remain to be fully clarified. Conclusion: Although progress has been made, the precise role of gut bacteria in diabetes remains unclear. A better understanding of these mechanisms is crucial for developing diagnostic and therapeutic strategies, and further human studies are needed to confirm findings from animal models.
Poczta et al. (Tue,) studied this question.