Resveratrol is a polyphenol antioxidant that may help to prevent heart disease, cancer, diabetes, and early signs of aging. In fact, resveratrol has been shown to influence gene expression to turn on factors that code for longevity in cells. Natural sources of resveratrol are red wine, grapes, peanuts, berries, chocolate, certain vines and a plant known as Japanese knotweed. Despite the many proposed health benefits of resveratrol, there are some negative effects with this compound, especially for those using certain drugs.
Resveratrol may interact with several medications. The Linus Pauling Institute reports that resveratrol may inhibit cytochrome 3A4, which may cause interactions with HMG-CoA reductase inhibitors, calcium channel agonists, anti-arrhthmic agents, HIV protease inhibitors, immunosuppressants, antihistamines, and erectile dysfunction medications. In addition, the natural blood pressure-lowering and anti-coagulant effects of resveratrol may cause interaction with blood pressure, anti-platelet, and anticoagulant medication, as well as NSAIDs such as aspirin and ibuprofen.
Resveratrol has shown both estrogen agonist and estrogen antagonist effects in cell culture studies. Estrogen agonists act to simulate the effects of endogenous estrogens. Antagonists of the estrogen hormone bind to receptor sites, blocking the effects of the hormone. Resveratrol has a similar chemical structure to synthetic estrogen agonists. The estrogen hormone can aggravate estrogen-dependent tumors in prostate and breast cancers. These tumors have many estrogen receptors, because they require the hormone to be able to grow. The Linus Pauling Institute recommends that more research is needed before those at risk for tumor growth ingest concentrated resveratrol supplements.
Although rare, anecdotal gastrointestinal side effects have been reported by resveratrol users. Stomach upset and cramping, diarrhea, and/or decreased appetite may occurwith large doses of resveratrol. Dietary supplements affect each individual differently, so some may be more susceptible to digestive side effects than others.
Resveratrol has been shown to have natural anti-inflammatory effects in the body, according to the Life Extension Foundation. By inhibiting COX enzymes that cause inflammation on a cellular level, resveratrol should theoretically help with conditions such as osteoarthritis. However, some people have reported joint pain and tendinitis with resveratrol use. Commonly affecting the Achilles tendon, resveratrol has also caused joint pain in other areas, sometimes accompanied by tingling and/or numbness in arms, legs, hands and feet.