Nutritional Medicine , Separating Fact from Fiction
Almost 80% of patients who undergo gastric bypass surgeries to lose weight show abnormal glucose tolerance when administered a glucose challenge. Some patients are downright hyperglycemic to the point they could be diagnosed as diabetic according to a news release from the American Society of Metabolic and Bariatric Surgery meeting awhile ago.
The working hypothesis, according to researchers, is that there is an enhanced insulin response which triggers low blood sugar with a corresponding increase in appetite. The rapid emptying of the gastric pouch is more than likely the cause for the enhanced insulin response. The combination of the rapid emptying of the pouch and low blood sugar are causes for increased appetite.
This finding has raised questions regarding whether the gastric bypass should remain the gold standard for weight loss for the morbidly obese. At the very least, it was suggested that a valve be inserted in the bypass procedure.
Patients are alarmed at the rapid increase in weight and surprised at the ravenous appetite that develops so soon after a meal.
Sixty-three patients were clinically studied who had undergone gastric bypass procedures. All the patients had a 100 g glucose tolerance test where the glucose was measured one and two hours after a meal. The investigators defined low blood sugar as less than 60 mg/dl or a decrease of 100 mg/dl or more within two hours of a meal challenge and no glucose value exceeding 200 mg/dl. They defined hyperglycemia as any value >200 mg/dl.
Glucose tolerance tests showed six patients with hyperglycemia, including five who had normal fasting levels. Furthermore, 26 additional patients were identified who had reactive hypoglycemia (low blood sugar) and another eight who had both low and high blood sugars.
The abnormal swings in blood glucose stimulated the researchers to comment that care must be taken when commenting that bariatric surgery can cure diabetes. In addition, this finding lends thought to what should be done in the future to better serve the needs of the bariatric population since the goal is to take weight off and keep it off while remaining healthy.
The findings suggest that alterations in the gastric bypass procedures need to be considered such as the use of valves or possibly using the vertical-sleeve gastrectomy and duodenal switches that are not as severely malabsorptive.