AMSTERDAM — Initiation of moderate daily alcohol consumption among patients with type 2 diabetes results in decreased fasting plasma glucose levels, particularly among patients with worse control at baseline, Iris Shai, Ph.D., reported at the annual meeting of the European Association for the Study of Diabetes.
Alcohol may inhibit hepatic glucose production—as does the antidiabetic drug metformin—and also has been associated with beneficial cardiovascular effects. A recent meta-analysis of observational studies suggested that moderate alcohol consumption is associated with a reduced risk of coronary heart disease mortality among patients with type 2 diabetes, and that the beneficial association is greater than among nondiabetics (Diabetologia 2006;49:648–52).
But although several short-term intervention studies have found a decrease in fasting plasma glucose (FPG) levels in diabetic patients with moderate alcohol intake, other studies have not, said Dr. Shai, of the Ben-Gurion University of the Negev, Beer-Sheva, Israel.
A randomized, controlled intervention study to investigate the association was jointly sponsored by the Israeli Diabetes Research Group; Harvard University, Boston; the Tishbi Estate Winery, Israel; and Admiral Imports, Cedar Grove, N.J. A total of 109 initially nondrinking (defined as one drink or less per week) patients with type 2 diabetes aged 40–75 years were randomized to either 150 cc of wine (13 g alcohol, 100 kcal) or the same amount of nonalcoholic diet malt beer (0 g alcohol, 30 kcal) during dinner, both served in the same standard measured glass. The wine group could choose either dry red (merlot) or white (sauvignon blanc). Three-fourths chose the red, noted Dr. Shai, who is also a registered dietician.
Participants met with the nurse study coordinator, physicians, and dieticians several times during the trial. All participants received individual dietary counseling, including identical nutritional strategies to achieve glycemic control without aiming for dramatic weight loss. Both groups were instructed to reduce their carbohydrate intake at breakfast and/or lunch but not at dinner, the wine group by 100 kcal and the controls by 30 kcal. Prior to each visit, the subjects filled in 3-day diaries of their food and drink consumption.
Of the 201 patients screened, 126 were eligible, 109 were randomized, and 91 completed the study. Dropouts were higher among the control group (26% vs. 12% of the intervention group). “Most were disappointed not to be assigned to the wine group,” Dr. Shai said. The dropouts had significantly higher baseline FPG levels (167 vs. 140 mg/dL), she noted.
At baseline, the 61 men and 48 women who were randomized ranged in age from 41 to 74 years, had an average FPG of 144.5 mg/dL, a hemoglobin A1c (HbA1c) level of 7.39%, blood pressure of 133.7/76.5 mm Hg, and body mass index of 30.1 kg/m
In contrast to the FPG, there were nonsignificant increases in 2-hour postmeal glucose levels, based on an average of self-measurements. Within the alcohol group, there were significant decreases in HbA1c (from 7.37% to 7.07%), LDL cholesterol (96.65 to 85.11 mg/dL), and waist circumference, but not in HDL cholesterol. These changes did not differ significantly between the two groups, however, she said. (HbA1c values dropped slightly in the controls, from 7.08% to 6.84%.)
At 6 months after the start of the study (3 months after its termination), 61% of the alcohol group thought the alcohol was beneficial to them, and 49% were continuing to drink alcohol in moderation, ranging from one drink a week to one a day.
In response to an audience member's question about red vs. white wine, Dr. Shai said that the group plans to break down the data to see if there was a difference. But, she added, the study was deliberately designed to examine the effects of ethanol per se, rather than those of any particular components that are unique to red wine. She also cautioned that longer intervention studies will be necessary to determine the efficacy and safety of initiating moderate alcohol consumption in people with type 2 diabetes who don't already drink.