But grapes -- or the chemicals within them, especially oligomeric proanthocyanidin complexes (OPCs) -- have been touted as powerful antioxidants. Some people believe they could help treat a number of conditions, from heart disease to cancer to aging skin, although scientific evidence is mostly lacking for those conditions. However, there is good evidence that grape seed extract can help treat chronic venous insufficiency and edema.

A study of healthy volunteers found that taking grape seed extract did substantially increase levels of antioxidants in their blood. Antioxidants are substances that destroy free radicals -- harmful compounds in the body that damage DNA (genetic material) and even cause cell death. Free radicals are believed to contribute to aging, as well as the development of a number of health problems, including heart disease and cancer.

 

Plant Descriptio 

Grapes are native to Asia near the Caspian Sea, but they were brought to North America and Europe. This plant's climbing vine has large, jagged leaves, and its stem bark tends to peel. The grapes may be green, red, or purple.

What's It Made Of?

Vitamin E, flavonoids, linoleic acid, and OPCs are highly concentrated in grape seeds. These compounds can also be found in lower concentrations in the skin of the grape. OPCs are also found in grape juice and wine, but in lower concentrations. Resveratrol is another of grape's compounds which is related to OPCs and found mainly in the skins. Resveratrol has become very popular as an antioxidant and is being studied in connection with a variety of diseases.

Medicinal Uses and Indications 

Today, standardized extracts of grape seed may be used to treat a range of health problems related to free radical damage, including heart disease, diabetes, and cancer. Grape seed extract has also been shown to protect against bacterial infections, such as Staphylococcus aureus. Some studies -- mostly in animals -- support these uses.

Flavonoids found in red wine may help to protect the heart by lowering "bad" LDL cholesterol. The so called "French paradox" is the belief that drinking wine protects people living in France from developing heart disease at the high rates seen in people living in the United States. So far, however, there is no clear evidence that taking grape seed extract helps reduce heart disease. Some researchers speculate that the alcohol in the wine, and not the flavonoids, could be responsible for any healthful effects. Others think it could be the combination of alcohol and flavonoids.

Drinking alcohol to protect against heart disease is not advocated by the American Heart Association and other organizations because of the potential for addiction and other serious problems, such as car accidents and the increased risk of hypertension, liver disease, breast cancer, and weight gain. If you do drink red wine, you should have no more than 2 glasses (20 g ethanol) per day if you are a man, and no more than 1 if you are a woman.

Chronic venous insufficiency

In chronic venous insufficiency, blood pools in the legs, causing pain, swelling, fatigue, and visible veins. A number of high quality studies have shown that OPCs from grape seed can reduce symptoms.

Edema

Edema -- swelling caused by surgery or an injury -- seems to go away faster when people take grape seed extract. Edema is common after breast cancer surgery, and one double blind, placebo controlled study found that breast cancer patients who took 600 mg of grape seed extract daily after surgery for 6 months had less edema and pain than those who took placebo. Another study found that people who took grape seed extract after experiencing a sports injury had less swelling than those who took placebo.

High cholesterol

There isn't enough evidence to say whether taking grape seed extract can lower cholesterol, although two preliminary studies showed promising results. A study of 40 people with high cholesterol looked at whether taking grape seed extract, chromium, a combination of both, or placebo for 2 months would lower cholesterol. The combination of grape seed extract and chromium was more effective than either grape seed alone or placebo in lowering total and LDL ("bad") cholesterol.

Another study looked at the effects of a proprietary grape seed extract on lipid peroxidation (the breakdown of fats in the blood) in a group of heavy smokers. In the study, 24 healthy male smokers (aged 50 years or greater) took either placebo or 2 capsules (75 mg of a grape procyanidin extracts and soy phosphatidalcholine), twice daily for 4 weeks. "Bad" LDL cholesterol levels were lower in those taking the grape seed supplement than those taking placebo.

High blood pressure

Theoretically, grape seed extract might help treat hypertension or high blood pressure. Antioxidants, like the ones found in grape seed, help protect blood vessels from damage. Damaged blood vessels can lead to higher blood pressure. In several animal studies, grape seed extract substantially reduced blood pressure. But human studies are needed to see whether grape seed extract helps people with high blood pressure.

Cancer

Studies have found that grape seed extracts may prevent the growth of breast, stomach, colon, prostate, and lung cancer cells in test tubes. However, there is no clear evidence yet whether it works in humans. Antioxidants, such as those found in grape seed extract, are thought to reduce the risk of developing cancer. Grape seed extract may also help prevent damage to human liver cells caused by chemotherapy medications. Talk to your doctor or pharmacist before combining antioxidants with any chemotherapy drugs to make sure they interact safely together and that they don't interfere with effects of the chemotherapy medications.

Other conditions

Grape seed extract is sometimes suggested for the following, although evidence is slight:

  • Alzheimer's disease
  • Diabetes (improving blood sugar control)
  • Improving night vision
  • Protecting collagen and elastin in skin (anti-aging)
  • Treating hemorrhoids
  • Protecting against oxidative rancidity and bacterial pathogens