What is the key to unlocking the health benefits of alcohol? Drinking a daily, single serving of wine seems to be the consensus among many scientists. And new research supports this mantra of moderate consumption, finding that a nightly tipple lowers risk factors that can lead to heart disease or complications from type 2 diabetes, increases levels of HDL (or "good") cholesterol and can improve the quality of sleep, specifically in people with type 2 diabetes.
Previous epidemiological research has demonstrated the benefits of moderate alcohol consumption for those who suffer from or are at risk of developing diabetes. Multiple studies have shown that wine drinkers who consume moderate amounts, specifically overweight women, are less likely to develop type 2 diabetes than those who abstain from alcohol. One study also found that red wine has the potential to regulate blood-sugar levels.
The authors of the new study, a team at Ben-Gurion University of the Negev in Israel, wanted to better understand the complicated relationship between diabetes and alcohol, specifically its effect on cardiometabolic risks, the factors that can lead to heart disease or type 2 diabetes. "We aimed to address the safety and efficacy of initiating moderate wine [consumption] in a long-term intervention among diabetics," Iris Shai, the study's principal investigator and a professor of nutrition and epidemiology of chronic diseases, told Wine Spectator.
They also hoped to determine whether the type of alcohol matters, as previous studies have pointed to ethyl alcohol as the compound responsible for health benefits, while others have asserted that red wine and it's polyphenols deserve some credit. "Whether red wine confers any advantage over white wine [was] unclear," the authors wrote in the study, published in the Oct. 20 issue of the Annals of Internal Medicine.
The researchers recruited 224 diabetic patients to participate in a two-year trial. Candidates were male and female, ages 40 to 75 years old, and all typically consumed less than one alcoholic drink per week before the trial began. For two years, participants were instructed to follow the Mediterranean diet, a nutrition regimen that has proven its effectiveness in lowering diabetes risk, and were randomly assigned to drink one glass of either mineral water, white wine or red wine every night with dinner. The researchers provided a 150ml measuring glass and the appropriate beverage—mineral water from Mey Eden or dry red or white wine from Golan Heights Winery—to maintain consistency.
The scientists collected questionnaires and blood samples from participants at the beginning of the trial, at six months and after two years. They recorded patients' demographics, lifestyle patterns, medications, symptoms and quality of life, as well as cholesterol and triglyceride levels, glycemic controls and liver function.
Participants consuming wine experienced significant health benefits compared to the water drinkers, researchers found. Both red and white wine drinkers saw cardiometabolic advantages, though the specifics of these advantages differed slightly. Red wine drinkers saw a more significant boost in HDL cholesterol, while white wine drinkers gained superior blood sugar controls.
The findings suggest that both ethyl alcohol, found in all wine, and polyphenols, found at a much higher level in red wine, contribute to the positive effects of wine consumption. "The alcohol was probably the main platform in both red and white wine, while the interaction of ethanol with phenols, mainly in the red wine, benefited the lipid profile," said Shai.
Wine drinkers reported no adverse symptoms and actually experienced an unexpected quality-of-life improvement. Both wine groups reported significantly improved sleep quality, while water drinkers did not.
Will doctors soon begin prescribing a nightly glass of wine to diabetes patients? Probably not just yet. "We could detect some overall moderate cardiometabolic advantage to combine a healthy Mediterranean diet with a glass of wine," said Shai. "But each individual could respond differently, and [each] should consult his practitioner first."
