Glycemic effects of moderate alcohol intake among patients with type 2 diabetes: a multicenter, randomized, clinical intervention trial

OBJECTIVE: In a randomized controlled trial, we assessed the effect of daily moderate alcohol intake on glycemic control in the fasting and postprandial states in patients with type 2 diabetes who previously had abstained from alcohol.

RESEARCH DESIGN AND METHODS: We randomly assigned 109 patients (41-74 years old) with established type 2 diabetes who abstained from alcohol to receive 150 ml wine (13 g alcohol) or nonalcoholic diet beer (control) each day during a 3-month multicenter trial. The beverages were consumed during dinner. Diet and alcohol consumption were monitored.

RESULTS: During the intervention, 17% of participants (12% from the alcohol group) dropped out, leaving 91 who completed the trial. Within the alcohol group, fasting plasma glucose (FPG) decreased from 139.6 +/- 41 to 118.0 +/- 32.5 mg/dl after 3 months compared with 136.7 +/- 15.4 to 138.6 +/- 27.8 mg/dl in the control subjects (P(v) = 0.015). However, alcohol consumption had no effect on 2-h postprandial glucose levels (difference of 18.5 mg/dl in the control group vs. 17.7 mg/dl in the alcohol group, P(v) = 0.97). Patients in the alcohol group with higher baseline A1C levels had greater reductions in FPG (age-adjusted correlation -0.57, P(v) < 0.001). No significant changes were observed in the levels of bilirubin, alkaline phosphatase, alanine aminotransferase, or aspartate aminotransferase, and no notable adverse effects were reported. Participants in the alcohol group reported an improvement in the ability to fall asleep (P(v) < 0.001).

CONCLUSIONS: Among patients with type 2 diabetes who had previously abstained from alcohol, initiation of moderate daily alcohol consumption reduced FPG but not postprandial glucose. Patients with higher A1C may benefit more from the favorable glycemic effect of alcohol. Further intervention studies are needed to confirm the long-term effect of moderate alcohol intake.