Editors' ChoiceType 2 Diabetes

Demystifying the “Magical Cure” for Diabetes

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Science Translational Medicine  08 May 2013:
Vol. 5, Issue 184, pp. 184ec76
DOI: 10.1126/scitranslmed.3006449

Reducing your stomach to the size of a walnut would perhaps seem an unthinkable intervention for the treatment of type 2 diabetes (T2D). Yet despite trepidation regarding surgical complications, irreversible anatomical changes, and potential life-long medical consequences, Roux-en-Y-gastric bypass surgery (RYGB) is now a treatment option for patients struggling with T2D as well as obesity, offering what has been touted as a “magic cure” for diabetes. Recent studies have demonstrated that in patients with T2D, RYGB results in rapid improvement in glucose metabolism and in many cases a reversal of diabetes. The mechanism for this phenomenon is not well understood; theories include postsurgical changes in incretins and adipokines, their interactions within the endocrine axes, and caloric restriction.

Harnessing these mechanisms could have enormous implications for clinical interventions. In a recent study, Jackness et al. set out to elucidate the mechanisms responsible for the dramatic improvement in glucose tolerance within days of RYGB. The study included 25 obese patients with T2D (hemoglobin A1c 8.4%) taking oral anti-hyperglycemic medications ± insulin. Eleven patients underwent RYGB. Fourteen obese patients did not undergo RYGB but rather were admitted to a research unit and placed on a post-RYGB–mimicking, very-low-calorie diet (VLCD) (500 kcal/day) consisting mainly of pureed fruits and vegetables, whey protein, and low-fat milk. After only 3 weeks, patients treated with either intervention—RYGB or VLCD—showed essentially the same improvement in glucose tolerance (assessed with frequently sampled IV glucose tolerance testing), hormonal profile (with the exception of greater increases in glucagon-like peptide-1 and adiponectin with RYGB), and percent bodyweight loss (8.1 and 7.2%, respectively). Importantly, in both the RYGB and VLCD groups a majority of patients were able to discontinue taking anti-hyperglycemic medications (72.7 and 71.4%, respectively).

Limitations of this study include nonrandomization, a small sample size that predominantly consisted of minorities, groups with similar but not matched baseline characteristics, and not admitting the RYGB group to the research unit for the VLCD treatment. Because this study was designed to examine short-term effects, it does not provide information regarding the long-term mechanisms involved in the metabolic benefits of RYGB. Yet this study does raise the possibility that in the short term, the rapid “magical cure” for diabetes observed with RYGB may largely reflect the requisite severe caloric restriction subsequent to surgery.

C. Jackness et al., Very low calorie diet mimics the early beneficial effect of roux-en-y gastric bypass on insulin sensitivity and beta-cell function in type 2 diabetic patients. Diabetes, 22 April 2013 (10.2337/db12-1762 ). [Abstract]

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