Resveratrol

Resveratrol is a naturally-occurring polyphenol compound that is found in red wine, red or purple grapes, some berries, and dark chocolate. Resveratrol has been touted as a potential remedy for a range of age-related conditions, including heart disease, diabetes, cancer, and Alzheimer's disease.

Resveratrol is also said to contribute to the "French paradox" — the observation that people living in France tend to eat a lot of cheese, butter, and other fatty foods yet have a low incidence of heart disease. Consumption of the compound has been found to mimic a calorie-restricted diet, according to a study published in 2012.1

Health Benefits
Much of the research pointing to the benefits have been laboratory or animal-based studies. So far, research on resveratrol's effectiveness in humans has yielded mixed results. Here's a look at some key study findings:

Heart Health
For a review published in Clinical Nutrition in 2015, researchers analyzed six previously published studies on the effects of resveratrol on blood pressure and concluded that resveratrol didn't significantly reduce blood pressure. Higher doses of resveratrol (over 150 mg per day), however, were found to significantly decrease systolic blood pressure (the top number on a blood pressure reading).2

Another review, published in the International Journal of Cardiology in 2015, examined the effectiveness of resveratrol on cardiovascular risk factors. After analyzing 10 previously published studies, researchers concluded that the analysis did not suggest any benefit of resveratrol supplementation on heart disease risk factors, including levels of total cholesterol, LDL cholesterol, triglycerides, blood pressure, and C-reactive protein (a blood protein that is raised when there is inflammation, including in heart disease).3

Aging
There's some evidence that resveratrol may not prolong life, according to research on people living in Tuscany who consume a diet rich in resveratrol from food sources like red wine. In a study published in JAMA Internal Medicine in 2014, 783 men and women 65 years or older were followed from 1998 to 2009. During that time, intake of red wine (as measured by urine levels of resveratrol metabolites), didn't change the likelihood of dying from any cause, the incidence of heart disease or cancer, or markers of inflammation.4

Cancer
A number of preliminary studies suggest that resveratrol may have anti-cancer effects. In a 2016 animal study, for instance, resveratrol suppressed ovarian tumor regrowth after chemotherapy. Published in Cancer, the study found that resveratrol inhibited the uptake of glucose by cancer cells (many cancer cells depend on glucose as their energy supply).5

Despite these findings, the data from the limited human clinical trials have shown inconsistent outcomes and randomized clinical trials are needed to confirm the cancer-fighting effects of resveratrol. There is also some concern that resveratrol may influence levels of estrogen and other hormones.