The Anti-Cancer Effects of Grape Seed Extract

Red grapes

The Greek gods had it right: eating grapes and drinking wine is apparently a good idea if you want to avoid cancer.

Numerous studies have investigated the relationship between grape seed extract (GSE) and cancer, and the results are exciting. Grapes contain more power to prevent cancer rather than cure it, though cancer survivors can certainly call upon the grape for the potential to prevent recurrence.

Research proves that people who consume diets rich in fruits and vegetables have an overall lower risk of cancer. But why? Scientists suspect that the phytochemicals within plants are the magical compounds that fight cancerous changes within human cells.

Phytochemicals are compounds found in plants that offer many health benefits to people. The healthful chemicals are found in fruits, vegetables, whole grains, legumes and nuts. Research is emerging on phytochemicals, and it appears that the entire grape packs a powerful anti-cancer punch.

Science Goes Ape for Grapes

On a microscopic level, phytochemicals inhibit cancerous changes along all stages of tumor growth, from initiation to growth to metastasis. Phytochemicals are most effective at preventing cancerous changes when consumed in healthy quantities over long periods of time. Thus, suddenly increasing consumption of grapes following a cancer diagnosis is unlikely to cure the cancer, but it may increase a person’s immunity to fight the cancer naturally.

Grape seeds contain a group of phytochemical antioxidants known as proanthocyanidins. Researchers believe the anti-cancer benefits of GSE come from these proanthocyanidins, which contain more antioxidant power than vitamins C and E.

A number of the studies conducted on GSE and cancer have investigated cancers that affect epithelial cells, including cancers of the skin, colon, prostate, breast and lung. Though GSE hasn’t been clinically studied on mesothelioma, the cancer does most commonly occur in epithelial cells and thus may serve as a preventative measure for people exposed to asbestos.

Interesting results from scientific studies on GSE were published in recent years. Some of the findings include:

  • Topical application of GSE on skin cancer tumors in mice reduced the amount of tumors that developed and reduced the size of existing tumors.
  • Dietary feeding of GSE to mice prevented skin papillomas from turning into carcinomas.
  • GSE significantly inhibited a type of precancerous colon lesion in a study on rats.
  • Multiple studies found that GSE causes prostate cancer cells to die.

Research also shows that GSE may enhance the effectiveness of cancer treatments such as chemotherapy. A 2004 study found that grape seed extract enhanced the effects of the chemotherapy drug doxorubicin in breast cancer patients. Doxorubicin is often used to treat mesothelioma patients.

Grab a Grape and a Glass

It turns out that all parts of grapes contain anti-cancer properties, not just the seeds. Scientific studies found cancer-fighting compounds in the following parts: grape skin, grape flesh, whole grapes and grape-derived raisins.

Studies on other parts of the grape as an anti-cancer food report equally encouraging results as those on grape seed extract:

  • A case control study found that increased consumption of grapes was linked with reduced breast cancer risk in Korean women.
  • In another Korean study, researchers report that daily grape juice consumption led to reduced DNA damage.
  • A scientific study on the extract of dried Greek raisins concluded that the extract stopped the growth of gastric cancer cells.
  • An extract of the skin of muscadine grapes inhibited the growth of epithelial prostate cancer cells in a 2007 study.

One of the most potent phytochemicals found in grapes is resveratrol, which is most concentrated in the skin of dark-colored grapes. Thousands of studies have shown the anti-cancer effects of resveratrol, which include reduced tumor incidence, reduced precancerous lesions, and blockage of several cancer-promoting biological compounds (such as COX-2).

Much of the funding behind the thousands of resveratrol studies come from the wine industry. Researchers believe some of the health properties in red wine may be attributed to resveratrol.

Grapeseed oil is another grape seed product that offers health benefits, though it isn’t regulated or measured for potency like grape seed extract is. The International Journal of Food Sciences and Nutrition published a study this month that investigated whether grapeseed oil could affect inflammation and insulin resistance in overweight or obese women. In the group of women who consumed grapeseed oil, insulin resistance improved and inflammation was reduced.

To take advantage of the health benefits of grapes, find a high-quality GSE supplement at a health food store, eat table grapes, and drink red wine in moderation. Some tasty table grape varieties include black, white (green), concord and Thompson grapes.

Toss on a toga, grab a bunch of you your favorite grapes, and treat yourself to a little red wine. The Greek gods and science say it’s a good idea.


Joining the team in February 2008 as a writer and editor, Michelle Whitmer has translated medical jargon into patient-friendly information at Asbestos.com for more than eight years. Michelle is a registered yoga teacher, a member of the Academy of Integrative Health & Medicine, and was quoted by The New York Times on the risks of asbestos exposure. If you have a story idea for Michelle, please email her at michelle@asbestos.com.

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