A team of Dutch researchers who pored over mountains of medical information dating back to the 1960s have come up with some good news for wine lovers: Drinking moderately may lead to a roughly 30 percent lower chance of developing type 2 diabetes.
The researchers, who are based in various clinics in Amsterdam, analyzed data from 15 health studies conducted around the world between 1966 and 2004, choosing them after reading more than 480 abstracts. The team, led by Lando Koppes at the VU University Medical Center, obtained information on 369,862 individuals, 11,959 of whom developed type 2 diabetes.
Type 2 diabetes is a chronic condition that occurs when the body can no longer regulate insulin levels. It results in a rise in blood sugar levels, possibly damaging organs and nerves. "The prevalence of type 2 diabetes is rising to epidemic proportions," the authors wrote, citing a predicted 37 percent increase--more than 100 million new cases--worldwide by 2030.
The authors concluded that moderate drinking could help prevent type 2 diabetes, along with regular exercise, a healthy diet and not smoking. "There are calculations that 91 percent of new type 2 diabetes cases could be attributed to the lack of adherence to [healthy] lifestyle behaviors, among which is the moderate consumption of alcohol," said the study, published earlier this year in Diabetes Care.
The 15 studies on alcohol and diabetes were chosen for the meta-analysis because all were peer-reviewed and they recorded comprehensive information on alcohol consumption, as well as other lifestyle factors. Each study measured participants' average daily consumption with servings in grams, and each category of drinker was compared to a control group of nondrinkers. The participants were studied for an average of 12 years.
For the meta-analysis, the team created its own gram-per-day categories of consumption, since the amount of alcohol that made up one "drink" varied greatly across the studies. For example, one serving equals 10 grams of alcohol in the United Kingdom, but 21 grams in Japan. In the United States, it is often defined around 12 grams, equal to a bottle of beer, 4 to 5 ounces of wine or about 1 ounce of liquor.
The Dutch researchers then placed the drinkers into five categories: less than six grams a day, six to 12 grams, 12 to 24 grams, 24 to 48 grams and more than 48 grams. By comparing the rates of type 2 diabetes in participants across the drinking categories, the researchers derived a risk factor for each group.
They found that, for both men and women, even low levels of alcohol consumption were beneficial, with those who drank less than six grams a day showing a 13 percent lower risk of developing type 2 diabetes than the nondrinkers. The three categories that the authors defined as moderate drinking--six to 12, 12 to 24 and 24 to 48 grams per day--fared best, showing reduced risks of 30 percent, 31 percent and 28 percent, respectively.
However, consuming more than 48 grams per day--more than four drinks per day--was linked to an increased chance of diabetes, 4 percent greater than nondrinkers.
In the United States, the very end of the Dutch-defined "moderate" spectrum (four drinks a day) is considered heavy drinking. Noted wine-and-health researcher R. Curtis Ellison, M.D., of the Boston University School of Medicine, who read the current study, suggested that, because the risk of type 2 diabetes increased with greater consumption, consuming up to two-and-a-half drinks a day is likely to be safer.