Question

"What advice can we give to patients with diabetes regarding alcohol consumption? Modest amounts of wine appear to be healthful for the heart. Evidence suggests that moderate alcohol improves insulin sensitivity. The American Diabetes Association's position seems to be `If you don't drink don't start, but if you drink don't stop.' What is an expert's opinion?"

Answer

A number of epidemiological studies have found an association between light to moderate alcohol amounts and decreased risk of type 2 diabetes, coronary heart disease, and stroke in persons without diabetes.

The greatest benefit of alcohol appears to fall within study quintiles that include people drinking 15–30 g/day of alcohol, which can be considered "light to moderate drinking." One drink of alcohol is commonly defined as 12 oz of beer, 5 oz of wine, or 1.5 oz of distilled spirits (hard liquor), each the equivalent of about 15 g of alcohol.

Studies suggest a "J" or "U" shaped curve: a small amount of alcohol per day is better than either no alcohol or a large amount of alcohol. The type of alcoholic drink doesn't seem to matter. Studies also report an increase in insulin sensitivity from moderate amounts of alcohol. Finally, studies indicate that light to moderate amounts of alcohol do not raise blood pressure, whereas chronic excessive amounts (greater than 30–60 g/day) do.

In people with diabetes, moderate alcohol consumption does not acutely affect glycemic control, and epidemiological studies indicate that moderate alcohol consumption for people with diabetes is associated with:

• A decrease in coronary heart disease (it may be one of the few ways to increase HDL cholesterol),
  
• A decreased risk for CHD, and
  
• A reduced risk of mortality.
  

Sounds like a wonderful therapy so far!

However, no cause-and-effect relationship has yet been established between alcohol drinking and diabetes. Without clinical evidence from adequately powered randomized controlled trials, it's hard to justify advising in favor of alcohol consumption.

While the data on alcohol and cardiovascular disease are still correlative, the toxic effects of alcohol are well established.

With regard to people with diabetes who have not previously been drinking alcohol routinely, there is evidence to suggest that they should not be encouraged to start. This is because alcoholism is, in part, genetically determined. Certain individuals have genes that predispose them toward alcoholism and currently there is no way to identify who these individuals may be. For example, sons of alcoholics are approximately 3 to 5 times more likely to become alcoholic than are sons of nonalcoholics; sons of alcoholics, adopted by nonalcoholic families in early life, are still 3 times more likely to become alcoholic than are similarly adopted sons of nonalcoholics. Hence, encouraging or condoning drinking in these individuals could contribute to the development of alcohol abuse and alcoholism.

Some people should not drink at all:

• Women who are pregnant or who are trying to become pregnant,
  
• Recovering alcoholics,
  
• People who plan to drive or engage in other activities that require attention or skill,
  
• People taking certain medications (e.g., antihistamines, anticonvulsants, antidepressants), and
  
• People with certain medical conditions (e.g., pancreatitis, advanced neuropathy, severe hypertriglyceridemia, alcohol abuse). Note though that there is no evidence to suggest that light-to-moderate amounts of alcohol have a detrimental effect on triglycerides, even in individuals with hypertriglyceridemia.

In summary, if a patient has diabetes and is not already drinking alcohol routinely, he or she shouldn't start. If a patient has diabetes and drinks a moderate amount of alcohol daily, he/she shouldn't escalate intake because high chronic alcohol intake (3 or more drinks per day) can cause deterioration in long- and short-term glucose metabolism. Heavy alcohol drinkers are strongly advised to reduce consumption.

The current American Diabetes Association position concerning alcohol is: If individuals choose to drink alcohol (the type doesn't make a difference), daily intake should be limited to one drink for adult women and two drinks for adult men; to reduce risk of hypoglycemia, alcohol should be consumed with food.

Madelyn L. Wheeler, MS, RD, CD, FADA, CDE, Coordinator¹, Marion J Franz, MS, RD, CDE, nutrition and health consultant² and Janice C. Froehlich, PhD³

¹ Research Dietetics at the Diabetes Prevention & Control Center of Indiana University School of Medicine.
² Minneapolis, Minn.
³ Indiana University School of Medicine, contributed to this article.
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References

American Diabetes Association: Nutrition Principles and Recommendations in Diabetes (position statement). Diabetes Care 27(Suppl. 1):S36 –S46, 2004.

Franz MJ, et al: Evidence-based nutrition principles and recommendations for the treatment and prevention of diabetes and related complications (Technical Review). Diabetes Care 25: 148–198, 2002.[Free Full Text]