Studies have found that some compounds of grape seed extractextractto get, separate, or isolate a desired active ingredient may be effective in relieving symptoms of chronic venous insufficiency (when veins have problems sending blood from the legs back to the heart) and reducing edema (swelling) after an injury or surgery.
Small randomized trials have found beneficial effects of grape seed extract for diabetic retinopathy (an eye problem caused by diabetes) and for vascular fragility (weakness in small blood vessels). Larger trials are needed to confirm these findings.
Grape seed extract contains antioxidantantioxidanta chemical substance that prevents cellular damage from free radicalss, which help prevent cell damage caused by free radicals (highly reactive molecules that can damage cell function). Preliminary studies have shown some beneficial antioxidant effects; however, more research is needed.
A study funded by the National Cancer Institute (NCI) found that grape seed extract did not reduce the hardening of breast tissue that can occur after radiation therapy for breast cancer.
NCI is also funding studies to evaluate whether grape seed extract is effective in preventing breast in postmenopausal women and prostate cancer.
The National Center for Complementary and Integrative Health (NCCIH) is studying whether the action of grape seed extract and its components may benefit the heart or help prevent cognitivecognitiverelating to the ability to think, reason, remember, and discern decline, Alzheimer’s disease, and other brain disorders. Another study is investigating the effects of grape seed extract on colon cancer.
Grape seed extract is generally well tolerated when taken by mouth. It has been used safely for up to 8 weeks in clinical trials.
Side effects that have been reported include a dry, itchy scalp; dizziness; headache; high blood pressure; hives; indigestion; and nausea.
Interactions between grape seed extract and medicines or other supplements have not been carefully studied.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.