Introduction: As life expectancy increases, the burden of chronic degenerative diseases is more evident. Diabetes and neurologic conditions such as Alzheimer's, Parkinson's and Huntington's diseases are clear examples of such burden. This review explores the links between these conditions with the objective of considering alternative therapeutic approaches for neurodegenerative diseases.

Background: Diabetes mellitus type 2 (DM2) is a major public health challenge that we face today; it is the first cause of disability and is associated with the main causes of death in our country. In Mexico City, it was reported that more than 79% of diabetic patients did not have optimal levels of HbA1c (<6.5%), while 47% are not properly controlled (HbA1c> 9%). Metabolic surgery is the best treatment option for DM2, yet the presumed involved mechanisms are not traditionally considered. Objective: To provide an update on the mechanisms involved in the remission of DM2 following metabolic surgery. Methods: Narrative review of the literature, using MeSH terms, until June 1, 2018, encountering 83 articles considered pertinent. Methods: Narrative review of the literature, using MeSH terms, until June 1, 2018, encountering 83 articles considered pertinent. Results: DM2 remission after surgery depends on complex interactions between the microbiota, biliary acids and the intestinal epithelium, more so than of malabsortion or restrictive processes. Bipartition of the intestinal transit constitutes a surgical option based on the physiologic principles responsible of the remission of diabetes, and it is a simple and most secure procedure for the management of diabetes. Mechanisms include restoration/ enhancement of incretin secretion; as well as an improvement of bile acid concentration and microbiome manipulation, rather than the commonly accepted restriction and malabsorption. Intestinal transit bipartition is a novel and simple procedure that complies with the actual involved mechanisms, with comparable results in terms of safety and efficacy with the more complex and demanding techniques, such as the gastric bypass. Conclusions: Metabolic surgery is the best treatment for DM2 in terms of remission and prevention of complications, modifying the secretion of enterohormones, the concentration of biliary acids, and the modification of the microbiota