Resveratrol (trihydroxy-trans-stilbene) is a natural compound found in red grape skin, Japanese knotweed (Polygonum cuspidate), peanuts, blueberries and a couple of other berries. It is a very powerful antioxidant that is produced by some plants to defend them against environmental stresses. Antioxidants neutralize free radicals, which are believed to be the cause of aging. The Japanese knotweed is the plant source of the highest resveratrol content.

A significant amount of resveratrol is produced in the skin of grapes to defend the plant against fungal diseases and sun damage; so the wine has higher levels of resveratrol compared to other natural food. Red wine contains a little amount of resveratrol, 1 to 2 mg per 8 ounces of red wine. Although Red wine has much more resveratrol than white wine because red wines are fermented with the grape skins for a much longer time than white wines. The reason there are so many of the antioxidants including resveratrol that are naturally present in the grape skins is extracted into the wine. Resveratrol is also very present in the seeds and pomace of grapes.

Grapes grown in wet environments tend to have more resveratrol than grapes grown in more dry conditions. The theory behind this phenomenon is that grapes grown in humid climates produce more resveratrol to fight damaging fungus (i.e. grapes cultivated in dry conditions do not need to produce as much resveratrol to survive).

Resveratrol has been thought to be responsible for low rates of heart disease in the French population compared to other residents, in spite of the fact that they have many risk factors including a high-fat diet, smoking, and consumption of high amounts of coffee. All of these are known to have high cholesterol, high blood pressure, stroke and heart attacks. This benefit in the French population is due to the consumption of red wine, which is a source resveratrol. Other ingredients in wine or other factors may contribute to longevity seen in the French.

Resveratrol is a dietary supplement from red wine extracts, grape seed extracts, and Japanese knotweed extracts among others. Supplements on the market mostly come from Japanese knotweed because this plant has one of the highest concentrations of resveratrol found in nature.

The amount of resveratrol and the purity of it in supplements can vary widely. Micronized Resveratrol is available in pill or powder form since Resveratrol is not well-absorbed orally. The process of micronization significantly reduces the average particle size of a compound and increases absorption. Resveratrol is also available in solution form.

How does Resveratrol work?

Resveratrol protects the DNA of a cell and is a powerful antioxidant. Antioxidants can help prevent this cell damage caused by free radicals. Free radicals are atoms caused by pollution, sunlight and our bodies natural burning of fat that can lead to cancer, aging and brain degeneration.

What are the benefits of taking Resveratrol?

Resveratrol has been known to have many health benefits like protecting the heart and circulatory system, lowering cholesterol, and protecting against blood clots which are the reason heart attacks and stroke occurs. Animal studies have suggested it can reduce blood sugar levels. Since resveratrol is considered an antioxidant, it is often promoted to reduce the incidence of various cancers. Studies on animals also suggest resveratrol may lower brain plaque levels in Alzheimer’s disease. But, well-controlled, human clinical trials are lacking in all of these areas, and many of the resveratrol claims are based in animal studies in mice.

The clinical utility of resveratrol in humans is under investigation. Studies suggest there might be benefits of weight loss, reduction in insulin resistance, and reducing mortality in diabetes. Human research with resveratrol is becoming more involved with scientists studies. A small randomized study in the November 2011 issue of Cell Metabolism demonstrated that 150 mg of resveratrol once daily for 30 days significantly lowered mean systolic and arterial blood pressure, tumor necrosis factor (a marker of inflammation), plasma glucose and insulin concentrations, and plasma triglyceride concentrations, among other findings. Researchers note that longer studies at higher doses increase results.

What other drugs will affect Resveratrol?

Drug interaction studies with resveratrol have hardly been conducted. The probable interaction with blood thinners should be taken into consideration. Patients taking blood-thinning medications such as aspirin, warfarin, or clopidogrel should advise their doctor that they are taking resveratrol. Also, patients should always inform their health care providers of any dietary supplements or over-the-counter medications they use.

Who should not take Resveratrol?

Patients with blood disorders, that can cause bleeding, should be monitored by a physician while taking this product. People bout to have surgery should stop taking resveratrol two weeks before the surgery and not take it for two weeks after the surgery to reduce the risk of bleeding.

Don’t take resveratrol supplements or excessive amounts of natural foods containing resveratrol while pregnant or breastfeeding. There is a lack of research in this area to prove safety. Resveratrol should be avoided in children.

Resveratrol little estrogenic activity, and until more is known, women with cancers and other conditions that are estrogen sensitive should seek medical advice before taking resveratrol.

Resveratrol reduces the activity of enzymes involved in drug metabolism but whether it has a significant effect in humans has not been studied.

What are the possible side effects of Resveratrol?

Adverse effects of resveratrol in humans have not been reported. Long-term side effects are not known. A small study conducted in 2011 in obese patients given 150 mg per day of resveratrol noted little weight loss.