Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate. The effectiveness ratings for GRAPE are as follows:
Possibly effective for…
- Poor circulation can cause the legs to swell (chronic venous insufficiency or CVI). Taking grape seed extract or proanthocyanidin, a chemical in grape seeds, by mouth seems to reduce symptoms of CVI such as tired or heavy legs, tension, and tingling and pain. Research suggests that taking a specific type of leaf extract by mouth decreases leg swelling after 6 weeks.
- Eye stress. Taking grape seed extract by mouth might help decrease stress on the eyes from glare.
Possibly ineffective for…
- Hay fever. Taking the seed extract for 8 weeks before ragweed pollen season does not seem to decrease seasonal allergy symptoms or the need to use allergy medications.
- Nausea and vomiting caused by cancer drug treatment. Taking 4 ounces of chilled Concord grape juice 30 minutes before meals for a week following each cycle of chemotherapy does not seem to reduce nausea or vomiting caused by chemotherapy.
- Lower urinary tract symptoms (LUTS). The term LUTS is typically used to describe symptoms associated with an overactive bladder. Drinking Concord juice doesn’t seem to improve these symptoms in older men.
- Breast pain (mastalgia). Taking proanthocyanidin, a chemical found in seed extract, three times daily for 6 months does not reduce breast tissue hardness, pain, or tenderness in people treated with radiation therapy for breast cancer.
- Obesity. Drinking Concord juice or taking grape seed extract or grape pomace does not seem to reduce weight in overweight people. However, it might help to lower cholesterol control blood sugar.
Insufficient evidence to rate effectiveness for…
- Aging skin. Early research shows that taking a specific combination product containing grape skin extract, marine collagen peptides, coenzyme Q10, luteolin, and selenium for 2 months might improve some markers of aging skin such as elasticity. But it doesn’t seem to improve skin moisture or how the skin appears based on age.
- Hardening of the arteries (atherosclerosis). Early research shows that taking a specific product containing grape seed oil, garlic, hops, green tea, and antioxidants for 1 year might help prevent cholesterol plaques from forming in the arteries. But it doesn’t appear to prevent the growth of plaques already present in the arteries. It also doesn’t appear to improve levels of cholesterol.
- Athletic performance. Early research shows that taking 400 mg of extract daily for one month might increase an athlete’s overall power when jumping, but not the initial power or maintaining power. Other early research shows that drinking juice prepared from whole grape powder does not improve how well the body uses oxygen or running ability.
- Eczema (atopic dermatitis) . Early research shows that applying a cream containing vitamin E and chemicals found in grapes and green tea doesn’t reduce symptoms of eczema.
- Heart disease. There is some early evidence that drinking juice or red wine might reduce risk factors linked with heart disease, such as inflammation, clot formation, and oxidative damage to blood fats. But it’s not known if grape products specifically reduce heart disease risk.
- Memory and thinking skills (cognitive function). Early research shows that drinking Concord juice helps middle-aged women focus while driving. Also taking a grape fruit extract for 12 weeks seems to improve attention, language, and memory in older people without age-related memory problems. It’s unclear if it improves mental function or memory in older people with age-related memory problems.
- The decline in memory and thinking skills in older people is more than what is normal for their age. Most early research suggests that grape does not improve mental function or memory in older people with memory problems.
- Colon cancer, rectal cancer. Taking a product containing grape seed extract and other ingredients while being treated with cancer drugs seems to help prevent colon and rectal cancer from progressing. But it doesn’t seem to improve survival.
- Vision problems in people with diabetes (diabetic retinopathy). Early research shows that taking specific grape seed extract products might slow the progression of eye damage caused by diabetes.
- High cholesterol. Taking grape seed extract or grape extract might reduce some measures of cholesterol and blood fats called triglycerides by a small amount in people with high cholesterol. It doesn’t seem to improve high-density lipoprotein (HDL or “good”) cholesterol. But some studies disagree, and it is not clear which product or dose might work best.
- High blood pressure. Most research has evaluated the seed extract or isolated chemicals from a grape called polyphenols in people with high blood pressure. Single studies show conflicting results. But analyses of multiple studies suggest that grape seed extract or polyphenols can slightly lower blood pressure in healthy people or those with high blood pressure. They seem to work best in people who are obese or those with metabolic syndrome. It might take 8 weeks for benefits to be seen.
- Dark skin patches on the face (melasma). Early research suggests that taking grape seed extract by mouth for 6-11 months reduces dark skin discolorations in Japanese women.
- Symptoms of the menopause. Taking the seed extract daily for 8 weeks seems to reduce hot flashes, anxiety, and some physical symptoms of menopause. It may also improve lean body mass and diastolic blood pressure (the bottom number in a blood pressure reading). But grape seed extract doesn’t seem to improve insomnia or depression.
- A grouping of symptoms that increase the risk of diabetes, heart disease, and stroke (metabolic syndrome). Some research shows that taking grape products can help to lower blood pressure and levels of blood fats like cholesterol in adults with metabolic syndrome. But it is not known if these changes decrease the risk for diabetes or other aspects of metabolic syndrome.
- Minor bleeding. An episiotomy is a surgical cut used to enlarge the opening of the vagina to aid in childbirth. Early research shows that using a product called Ankaferd blood stopper, which contains alpinia, licorice, thyme, stinging nettle, and grape vine helps to reduce bleeding during episiotomy repair. But it doesn’t reduce surgical time.
- Muscle soreness. Early research shows that drinking juice prepared from grape powder for 6 weeks before an arm exercise test does not reduce pain or swelling one or two days after the exercise.
- Ability to see in low-light conditions. Early research suggests that seed extract containing chemicals called proanthocyanidins might improve night vision.
- The build-up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD). Research shows that taking seed extract for 3 months improves some blood tests of liver damage in people with nonalcoholic fatty liver disease.
- Premenstrual syndrome (PMS). Early research suggests that taking a specific grape seed extract product might reduce PMS symptoms, including pain and swelling.
- Wound healing. Early research shows that applying a cream containing 2% grape seed extract reduces the time for wound healing after the removal of skin lesions. Early research also shows that applying an ointment containing 5% grape seed extract seems to help with wound healing in women recovering from C-section deliveries.
- Age-related macular degeneration (AMD).
- Attention deficit-hyperactivity disorder (ADHD).
- Canker sores.
- Chronic fatigue syndrome (CFS).
- Heavy menstrual periods.
- Liver damage.
- Treating varicose veins.
- Other conditions.
More evidence is needed to rate the effectiveness of grape for these uses.
Side Effects Of Grape
- When taken by mouth: Grape is LIKELY SAFE when consumed in amounts commonly found in foods. But keep in mind that, due to its size and shape, whole grapes are a potential choking hazard for children aged 5 years and younger. To reduce the risk, whole grapes should be cut in half or quartered before being served to children.
- Grape is POSSIBLY SAFE when taken by mouth in medicinal amounts. Grape seed extracts and fruit extracts have been used safely in studies for up to 12 months. A grape leaf extract has been used safely in studies for up to 12 weeks. Eating large quantities of grapes, dried grapes, raisins, or sultanas might cause diarrhea. Some people have allergic reactions. Some other potential side effects include stomach upset, indigestion, nausea, vomiting, cough, dry mouth, sore throat, infections, headache, and muscular problems.
- When applied to the skin: There isn’t enough reliable information to know if the grape is safe or what the side effects might be.
- When used in the vagina: There isn’t enough reliable information to know if it is safe or what the side effects might be.
Warnings & Precautions
- Pregnancy and breast-feeding: There isn’t enough reliable information to know if the grape is safe to use in medicinal amounts when pregnant or breast-feeding. Stay on the safe side and avoid using more than amounts normally found in foods.
- Bleeding conditions: Grape might slow blood clotting. Taking grape might increase the chances of bruising and bleeding in people with bleeding conditions. However, there are no reports of this occurring in humans.
- Surgery: Grape might slow blood clotting. It might cause extra bleeding during and after surgery. Stop using medicinal amounts of grape at least 2 weeks before a scheduled surgery.
The following doses have been studied in scientific research:
BY MOUTH: For poor circulation that can cause the legs to swell (chronic venous insufficiency or CVI):
A standardized red vine grape extract knows as AS 195 360 mg or 720 mg once daily for 6 to 12 weeks has been used.
A specific grape seed extract containing proanthocyanidin 150-300 mg daily for one month has also been used. Proanthocyanidin is one of the active ingredients in grape.
For eye stress:
A specific grape seed extract containing proanthocyanidin 200 mg daily for 5 weeks has been used.
Grape seed extract proanthocyanidin at a dose of 300 mg per day has also been used.
Consult your doctor or pharmacist.
All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.