Effect of alcohol ingestion on plasma glucose kinetics after Roux-en-Y gastric bypass surgery

Background: Roux-en-Y gastric bypass surgery (RYGB) increases the rate of alcohol absorption so that peak blood alcohol concentration is 2-fold higher after surgery compared with concentrations reached after consuming the same amount presurgery. Because high doses of alcohol can lead to hypoglycemia, patients may be at increased risk of developing hypoglycemia after alcohol ingestion. Objectives: We conducted 2 studies to test the hypothesis that the consumption of approximately 2 standard drinks of alcohol would decrease glycemia more after RYGB than before surgery. Setting: Single-center prospective randomized trial. Methods: We evaluated plasma glucose concentrations and glucose kinetics (assessed by infusing a stable isotopically labelled glucose tracer) after ingestion of a nonalcoholic drink (placebo) or an alcoholic drink in the following groups: (1) 5 women before RYGB (body mass index = 43 ± 5 kg/m2) and 10 ± 2 months after RYGB (body mass index = 31 ± 7 kg/m2; study 1), and (2) 8 women who had undergone RYGB surgery 2.2 ± 1.2 years earlier (body mass index = 30 ± 5 kg/m2; study 2) Results: Compared with the placebo drink, alcohol ingestion decreased plasma glucose both before and after surgery, but the reduction was greater before (glucose nadir placebo = −.4 ± 1.0 mg/dL versus alcohol = −9.6 ± 1.5 mg/dL) than after (glucose nadir placebo = −1.0 ± 1.6 mg/dL versus alcohol = −5.5 ± 2.6 mg/dL; P <.001) surgery. This difference was primarily due to an alcohol-induced early increase followed by a subsequent decrease in the rate of glucose appearance into systemic circulation. Conclusion: RYGB does not increase the risk of hypoglycemia after consumption of a moderate dose of alcohol.