Gastric bypass surgery is the most effective therapy for treating or reversing type 2 diabetes in very obese patients. Longstanding theory has shown that surgery can have unique, weight loss-independent effects in the treatment of diabetes. However, new research from the Washington University School of Medicine in St. Louis shows that weight loss after surgery, rather than the surgery itself, leads to metabolic improvements such as remission from diabetes. Photo credit: Mike Worful
Gastric bypass surgery is the most effective therapy for treating or reversing type 2 diabetes in very obese patients. Many achieve remission from diabetes after surgery and no longer require diabetes medication. This observation has led to the theory that gastric bypass surgery has unique, weight loss-independent effects in the treatment of diabetes, but this has remained a longstanding question in the field. New research from the Washington University School of Medicine in St. Louis now shows that weight loss after surgery, rather than surgery itself, leads to metabolic improvements such as remission from diabetes.
The researchers looked at severely obese patients with diabetes who had gastric bypass surgery and then lost 18% of their body weight. For example, for a patient who weighs 250 pounds, that would be 45 pounds. The researchers compared these patients with others who were also seriously ill with diabetes but had lost the same percentage of body weight through diet alone.
After reaching their weight loss goals, members of both groups experienced similar improvements in metabolism – such as: For example, lower blood sugar levels during the day, better insulin action in the liver, muscle and adipose tissue, and a reduction in the need for insulin and other diabetes medications. Because the group who lost weight from diet alone did as well as the surgical group, the researchers concluded that the improvements were due to weight loss rather than physiological changes resulting from the surgery itself.
The study was published in the New England Journal of Medicine on August 20.
"Gastric bypass surgery has been suggested to have therapeutic, metabolic effects that result in better glucose control and even remission from diabetes beyond those expected from weight loss alone," said senior investigator Samuel Klein, MD, Director of the Washington University Nutrition Center for Human. "We found, however, that gastric bypass surgery improves metabolic function by causing weight loss. There were no differences in diabetes medication reductions or in the rate of diabetes remission between surgical patients and those treated equally by diet alone Have lost weight. "
More than 40% of American adults are obese, and nearly one in ten is severely obese. Every year more than 250,000 people in the United States undergo bariatric surgery to help them lose weight. The gold standard procedure, called Roux-en-Y gastric bypass, was the most successful surgery in terms of total weight loss and long-term maintenance.
In this procedure, laparoscopic surgeons use a portion of a patient's football-sized stomach to create a pouch the size of a table tennis ball that attaches directly to the small intestine and bypasses much of the upper part of the small intestine. In this study, gastric bypass procedures were reviewed by bariatric surgeon, Dr. med. J. Chris Eagon, an associate professor of surgery, and Dr. Shaina R. Eckhouse, an assistant professor of surgery.
Klein's team compared 11 gastric bypass surgery patients who had diabetes with 11 others who had diabetes and achieved equivalent weight loss from diet alone. The mean age of the patients in the diet group was about 55 years, while the mean in the operation group was 49 years. The patients in the operation group lost an average of 51 pounds while the patients in the diet group lost an average of 48 pounds. All study patients maintained this weight loss for several weeks before follow-up studies were performed.
Over a 24-hour period, the researchers used sophisticated techniques in a hospital to measure the subjects' metabolic responses to meals. They measured insulin sensitivity in the liver, adipose tissue and muscle tissue. They also analyzed the response of insulin-secreting beta cells in the pancreas and blood fatty acid levels, all of which contribute to the development of type 2 diabetes.
"Weight loss induced by gastric bypass surgery has been hypothesized to be different from weight loss caused by a low-calorie diet based on the fact that certain factors – such as increased bile acid levels, decreased branched chain amino acid levels, and changes in the gut microbiome – are common in surgical patients different and may be responsible for the unique therapeutic effects of gastric bypass surgery, "Klein said. "We found that all of these factors after weight loss were actually different in surgical patients than in patients who lost weight through diet alone. However, these changes were not associated with physiologically or clinically important metabolic benefits."
According to Klein, also a William H. Danforth Professor of Medicine and Nutrition and Head of the Department of Geriatrics and Nutrition, weight loss is the reason for improving metabolic function and reversing diabetes. Weight loss through diet produces the same beneficial metabolic effects as weight loss after surgery.
In an accompanying editorial in the journal on the paper, researchers from Tufts University, Harvard University, Massachusetts General Hospital, and the University of Maine write that the study "delivers a simple and important message for clinicians and patients – the reduction of adipose tissue volume Whatever that means, blood sugar control will improve in people with type 2 diabetes. "
"However, it is extremely difficult and unrealistic for most people with obesity to lose 18% of their body weight with diet therapy alone," said Klein. "In contrast, gastric bypass surgery results in significant and sustained long-term weight loss, making it an effective therapy for people with diabetes."
Klein's study focused on the effects of gastric bypass surgery on metabolic function and did not investigate other medical complications associated with obesity.
"Our study does not rule out gastric bypass surgery having unique, non-weight loss effects on key clinical outcomes such as arthritis, lung function, or cancer risk that have not been assessed. However, when it comes to metabolic health, gastric bypass surgery is effective because it causes weight loss, "he said.
A strict diet explains the metabolic effects of gastric bypass surgery
Yoshino M, Kayser BD, Yoshino J, Stein RI, Schilf D, Eagon C, Eckhouse SR, Watrous JD, Jain M, Ritter R, Schechtman K, Patterson BW, Klein S. Effect of diet versus gastric bypass on metabolic function in diabetes . The New England Journal of Medicine, August 20, 2020. DOI: 10.1056 / NEJMoa2003697
Washington University Medical School
Major weight loss – whether through surgery or diet – has the same metabolic benefits (2020, Aug 19)
accessed on August 19, 2020
This document is subject to copyright. Apart from fair treatment for the purpose of private study or research, no
Part may be reproduced without written permission. The content is provided for informational purposes only.