Excessive alcohol consumption is associated with an increased risk in a number of health complications including high blood pressure, and heart and liver disease. However, when alcohol is consumed in moderation, especially red wine, there may be some health-related protective benefits. Red wine extracts, which are primarily composed of the powerful antioxidant resveratrol, are currently being marketed as heart-healthy supplements. While there is some scientific evidence that supports the benefits of resveratrol, there are also reports of potential side effects associated with resveratrol supplements.
While there are significant studies reporting the positive benefits of resveratrol and red wine extract, there are relatively few that document the potential negative side effects. According to the Linus Pauling Institute at Oregon State University, resveratrol has not been linked to any toxic or serious side effects in humans; however, the availability of clinical research data is limited. One of the known properties of resveratrol is its anticoagulation effects, which means that it inhibits the coagulation property of blood platelets that are important for blood clotting. While the anticoagulation effects by themselves are not necessarily a threat, when taken with prescription blood thinners, they may actually increase the effects and put you at risk for excessive bleeding.