Q: I’ve heard wonders about grape seed extract. Is it worth taking?
A: Scientific research has certainly begun to back up some—but by no means all—of the many beneficial uses claimed by proponents of grape seed extract (GSE). Most readily available in capsule or tablet form, grape seed extract is derived from the crushed seeds of wine grapes. Those seeds contain large concentrations of proanthocyanidins, chemical compounds that have potent antioxidant properties. The same compounds can also be found in red wine and, in much smaller amounts, white wine. But with the extract, you get the potential benefits without the booze.
In a Spanish study published in 2015, scientists showed that GSE can boost antioxidant activity in the body. Antioxidants, found in many fruits and vegetables, may protect against cell damage in our bodies—one of the many reasons to eat a healthy diet. Working with other compounds found in good food, antioxidants may help prevent heart disease, some forms of cancer, and other health problems. However, studies of antioxidant supplements have shown no such benefits.
A significant amount of the research into GSE has focused on its potential to protect against heart disease. The authors of a 2011 review of nine clinical trials report that GSE slightly lowered systolic blood pressure (the top number in a blood pressure reading) and heart rate. On the other hand, it had no apparent impact on diastolic blood pressure (the bottom number), nor did it lower cholesterol or curb inflammation. The studies the authors reviewed, however, were too small to make firm conclusions, positive or negative.
Other studies suggest that GSE may lower your risk of atherosclerosis, a hardening of the arteries that can cause heart attack and stroke. Larger studies need to be done to confirm this.
Regarding cancer prevention, a 2009 analysis of scientific studies on GSE noted that GSE contains phytochemicals, which show promise as cancer fighters. However, the studies the authors reviewed involved animals, not humans. NIH-funded research into GSE’s anti-cancer potential is underway.