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Small Amounts of Alcohol Slightly Increases Risk of Low Blood Sugar in Certain Diabetics

Dec. 13, 1999 (Tuscaloosa, Ala.) -- A beer or two after skipping a meal may not be a good idea for type 2 diabetic patients who take the prescription drugs known as sulfonylureas to treat their diabetes, according to a study by researchers at the University of New Mexico Health Sciences Center in Albuquerque.

Doctors have long known that there is a low risk of hypoglycemia (very low blood sugar levels that can cause symptoms including unconsciousness) during fasting periods among otherwise healthy, elderly patients with type 2 diabetes who take sulfonylurea medications. Now they have found out that the addition of even a relatively small amount of alcohol increases that risk to fasting individuals who are on insulin-release-stimulating drugs such as chlorpropamide, glyburide, glipizide, and glimeperide.

The study, conducted by Mark R. Burge, MD, and his colleagues, looked at the effect of giving the equivalent of one or two shots of alcohol to fasting elderly diabetic patients on sulfonylurea. In the study, fasting was defined as doing without food for 24 hours.

"Previous studies had demonstrated that intoxicating levels of blood alcohol resulted in increased insulin secretion and low blood sugars in nondiabetic individuals," Burge tells WebMD. "We wanted to quantify what the effects of low levels of alcohol would be on elderly type 2 diabetic patients who were fasting."

Burge and his fellow researchers had 10 type 2 diabetic patients, ranging in age from 65 to 71, go on two 24-hour fasts at least one week apart. These patients were all given glyburide once a day for the week before the fasting study took place. During hours 14 and 15 of the fasting studies, the subjects received injections in the vein of either a placebo fluid or alcohol equal to that of one or two ounces of beer, wine, or spirits. Then, every 30 to 60 minutes during the final 10 hours of the fast, blood samples were taken to measure the amounts of alcohol, blood sugar, insulin, and certain hormones.

The blood alcohol levels peaked at the lower legal limit of intoxication while blood sugar levels plummeted, according to the study.

"The absolute decline in blood sugar was greater in the patients who got the alcohol" than in those who were given placebo, Burge says. "These results indicate that a little bit of alcohol may increase your risk of hypoglycemia if you are on sulfonylurea drugs and haven't eaten."

There has been increased interest over the past few years about the potential health benefits of moderate intakes of alcohol. One large study showed an impressive decrease in the risk of cardiovascular death and overall mortality associated with alcohol intake among patients with type 2 diabetes. An interesting finding in this study is that the alcohol intake appears to reduce fatty acid concentrations in the bloodstreams of the subjects.