BACKGROUND: The ability of gastrointestinal surgical interventions, mainly bariatric surgery, to promote the control of type 2 diabetes, has already been well documented. AIM: To review the literature related to the effects of gastrointestinal surgery regarding type 2 diabetes, especially in relation to metabolic control and its physiopathology. METHODS: Literature was reviewed on Medline, pages on the internet, references from relevant articles and studies presented and published on the annals of the International Conference on Gastrointestinal Surgery to Treat Type 2 Diabetes, which occurred in Rome in 2007. CONCLUSIONS: Among all bariatric surgeries, biliopancreatic diversion, presented the best control rates for type 2 diabetes followed by gastric bypass and gastric banding. This control is related to weight loss and reduction on food intake. Biliopancreatic diversion and gastric bypass also presented important modifications in gut hormones. The most significant ones being: GLP-1, GIP, PYY, ghrelin, leptin, IGF-1, adiponectin. These hormones promote loss of appetite, promote actions over ß cells, increase the secretion of insulin, and increase insulin sensitivity. Two theories have been formulated to explain the changes observed on these hormones: the foregut theory, where the bypass of the duodenum and proximal jejunum avoids the secretion of an unknown factor that induces insulin resistance; and the hindgut theory, where the early presentation of food to the ileum anticipates the production of hormones that control diabetes. Recently, new promising procedures have been developed. Among them are the duodenal-jejunal bypass, ileal interposition, and intestinal resection associated to vertical gastrectomy. These new procedures are still considered experimental.
Bariatric surgery; Diabetes mellitus; Biliopancreatic diversion; Gastric bypass; Gastrointestinal hormones