Changes in Amino Acid Levels Following Gastric Bypass May Improve Diabetes

By: Almas Eftekhari

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Gastric bypass surgery is an effective weight-loss treatment for people with morbid obesity and has been shown to significantly improve type 2 diabetes. The procedure limits food intake and prevents the absorption of calories by reducing the size of the stomach and altering the flow of food into the small intestine. Though the resulting weight-loss can aid against diabetes, doctors notice healthier blood-sugar control and diminishing symptoms well before their patients begin to lose the weight. Up to 80% of people experience diabetes remission, but reasons for this are not known.

Two American Diabetes Association-supported researchers have discovered potential clues that may help explain why gastric bypass surgery provides these beneficial effects independent of weight loss. In a previous study, Christopher Newgard, Ph.D., of Duke University Medical Institute and the Sara W. Stedman Nutrition and Metabolism Center, found that increased circulating concentrations of certain kinds of amino acids (the building-blocks of proteins) are linked to insulin resistance and cardiovascular disease. Now in a more recent study, Blandine Laferrere, M.D., of St. Luke’s Roosevelt Institute for Health Sciences, observed that individuals undergoing bariatric surgery have dramatically reduced levels of these amino acids circulating in their body.

The study included twenty-one obese participants diagnosed with type 2 diabetes, ten of which received gastric bypass while the rest underwent a 1,000-calorie meal-replacement diet per day. Both groups lost the same amount of weight, but the diet group took about a month longer to do so and had higher levels of the amino acids present in their body. The surgery patients showed significant improvement in their blood-sugar levels and were able to discontinue their diabetes drugs entirely within one month of the procedure, while some of the dieters still needed their medications despite equivalent weight loss.

“Those changes in amino acids could be implicated in the mechanism of diabetes remission after gastric bypass,” said Dr. Laferrere. 

Dr. Newgard and Dr. Laferrere plan to focus on the effect of these amino acids on diabetes risk in future research. They are optimistic that their preliminary findings could lead to advancement in new diabetes treatments that are as effective as gastric bypass. This is important because the majority of people with type 2 diabetes do not qualify as candidates for the surgery. The procedure is advised only to patients with a body mass index (BMI) of 35 or higher, in addition to being relatively invasive and having risk of adverse side effects.

The results of the study are published in the April 27, 2011 issue of Science Translational Medicine.

(Laferrère B, Reilly D, Arias S, Swerdlow N, Gorroochurn P, Bawa B, Bose M, Teixeira J, Stevens RD, Wenner BR, Bain JR, Muehlbauer MJ, Haqq A, Lien L, Shah SH, Svetkey LP, Newgard CB. Differential metabolic impact of gastric bypass surgery versus dietary intervention in obese diabetic subjects despite identical weight loss. Science Translational Medicine. 2011 Apr 27;3(80):80re2.)