Page last updated:August 10, 2015
Critique 174: Two-year clinical trial of wine administration in diabetics who were previous abstainers or very-light drinkers — 19 October 2015

Observational epidemiologic studies have consistently found that moderate drinkers are at lower risk of cardiovascular disease (CVD); such alcohol consumption also lowers both the risk of diabetes as well as of CVD among diabetics. However, there have been few clinical trials of the administration of alcohol or wine among diabetics, and most have been for relatively short periods of time. Forum members welcomed the publication of the results of the present study, and consider that it provides valuable information on the relation between wine and cardiometabolic risk.

In this study, among 224 subjects with diabetes aged 40 to 75 years who were abstainers or very light drinkers (previously reported none or < 1 drink/week), the investigators carried out a randomized clinical trial of the effects of wine on cardiometabolic factors. The subjects were randomly assigned to 150 mL of mineral water, white wine, or red wine with dinner for 2 years; all groups followed a Mediterranean diet without caloric restriction. The study was described to subjects as a dietary intervention, and there were group sessions led by clinical dietitians each month for the first three months and then at 3-monthly intervals thereafter. The focus was on the Mediterranean diet, and wine was not discussed at these meetings. There was excellent compliance with the provided beverages (>80%) and excellent continued participation of subjects (94% for one year and 87% for the full two years).

The key results of this study were that the administration of 150 ml of red wine with dinner each evening, in comparison with mineral water, favorably affected many cardiometabolic factors, and especially led to an increase in HDL-cholesterol and apolipoprotein (a). The administration of similar amounts of white wine was also beneficial, and specifically improved measures of glycemic control.

Further, in 203 of the subjects, effects according to the genetic factors determining ADH were evaluated. In the study, 35.6% of subjects were homozygous for the polymorphism for “slow ethanol metabolism,” 21.3% were homozygous for that for “fast ethanol metabolism,” and 43% were heterozygous. Forum members agreed with the summary statement of the authors: “We found that diabetic patients who were slow alcohol metabolizers had improved glycemic control by initiating moderate wine consumption, which suggests that alcohol may play a role in glucose metabolism. In contrast, diabetic patients who were fast ethanol metabolizers benefited the most from the wine-induced BP-lowering effect, which suggests a mediatory role for ethanol metabolites.”

The study has important implications for advice to be given to diabetics. Most, but not all, Forum members agreed with the authors’ conclusion that “Initiating moderate wine intake, especially red wine, among well-controlled diabetics as part of a healthy diet is apparently safe and modestly decreases cardiometabolic risk.”

Reference: Gepner Y, Golan R, Harman-Boehm I, . . . Stampfer MJ, Shai I, et al. Effects of initiating moderate alcohol intake on cardiometabolic risk in adults with type 2 diabetes. A 2-year randomized, controlled trial. Ann Intern Med 2015; pre-publication. doi:10.7326/M14-1650

For the full critique of this paper by members of the International Scientific Forum on Alcohol Research, please click here.


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