Grape - What is it & How to use

Grape contains flavonoids, which can have antioxidant effects, lower the levels of low density lipoproteins (LDLs, or “bad cholesterol”), relax blood vessels, and reduce the risk of coronary heart disease. The antioxidants in grape might help to prevent heart disease and have other potentially beneficial effects. Red grape varieties provide more antioxidants than white or blush grape varieties.

Grape leaf might reduce inflammation and have astringent effects. In other words, grape leaf seems to be able to draw tissue together, which could help stop bleeding and diarrhea. These properties appear to be greatest in the red leaves.

Effectiveness

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 that can cause the legs to swell (chronic venous insufficiency). Taking grape seed extract by mouth seems to reduce symptoms of chronic venous insufficiency such as tired or heavy legs, tension, and tingling and pain. Research suggests that taking a specific grape leaf extract (AS 195, Antistax, Boehringer Ingelheim) 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 grape seed extract for 8 weeks before ragweed pollen season does not seem to decrease seasonal allergy symptoms or the need to use allergy medications.
  • Tissue hardness and pain caused by radiation. Research shows that taking proanthocyanidin, a chemical found in grape 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.
  • Nausea and vomiting caused by chemotherapy. Evidence shows that 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.
  • Weight loss. Evidence suggests that drinking Concord grape juice for 12 weeks does not reduce weight in overweight people.

Insufficient evidence to rate effectiveness for…

  • Athletic performance. Early research shows that taking 400 mg of grape extract daily for one month might increase an athlete’s overall power when jumping, but not the initial power or maintenance of power.
  • Heart disease. There is some early evidence that drinking grape juice or red wine might help to prevent heart disease by reducing cholesterol levels, reducing inflammation, and preventing clot formations.
  • Eye damage caused by diabetes (diabetic retinopathy). Early evidence suggests that taking a specific grape seed extract product (Endotelon) can slow the progression of eye damage caused by diabetes.
  • High cholesterol. Some research shows that taking 100 mg of grape seed extract twice daily for up to 2 months does not lower cholesterol levels in people with high cholesterol. However, other research shows that grape seed extract might lower cholesterol when taken in combination with other ingredients, including chromium or policosanol, tomato extract, and evening primrose oil.
  • High blood pressure. Research suggests that grape seed extract does not reduce blood pressure in healthy people or people with high blood pressure. However, in men with metabolic syndrome, a cluster of conditions that increase the risk for heart disease, taking freeze-dried, dehydrated whole grapes for 20 days seems to lower blood pressure. Additionally, some studies suggest that drinking grape juice can lower blood pressure in people with high blood pressure; however, other research shows that grape juice does not have this effect.
  • 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.
  • Age-related mental decline. Early research shows that drinking Concord grape juice daily for 12 weeks can improve verbal learning, but does not improve memory, in older people with age-related mental decline.
  • Metabolic syndrome. Early research suggests that whole grapes might improve some of the risk factors associated with metabolic syndrome, a cluster of conditions that increase the risk for heart disease, in men. Taking freeze-dried, dehydrated whole grapes for 30 days lowers blood pressure and increases blood flow. However, it is not known if these changes decrease the risk for diabetes or other aspects of metabolic syndrome. Also, other research shows that taking a specific product containing grape seed extract (Meganatural BP) for 4 weeks does not reduce blood pressure in people with metabolic syndrome.
  • Poor night vision. Early research suggests grape seed extract containing chemicals called proanthocyanidins might improve night vision.
  • Nonalcoholic fatty liver disease. Research shows that taking grape seed extract twice daily for 3 months improves some but not all markers of liver damage compared to vitamin C supplementation in people with nonalcoholic fatty liver disease.
  • Premenstrual syndrome (PMS). Early research suggests that taking a specific grape seed extract product (Endetelon) might reduce PMS symptoms, including pain and swelling.
  • Treating varicose veins.
  • Hemorrhoids.
  • Constipation.
  • Cough.
  • Attention deficit-hyperactivity disorder (ADHD).
  • Chronic fatigue syndrome (CFS).
  • Diarrhea.
  • Heavy menstrual periods.
  • Age-related macular degeneration (AMD).
  • Canker sores.
  • Liver damage.
  • Other conditions.

More evidence is needed to rate the effectiveness of grape for these uses.

Dose

The following doses have been studied in scientific research:

BY MOUTH:

  • For poor blood flow in the legs (chronic venous insufficiency):
    • Standardized red vine grape extract AS 195 (Antistax, Boehringer Ingelheim 360 mg or 720 mg once daily.
    • Grape seed extract as tablets or capsules dosed at 75-300 mg daily for three weeks followed by a maintenance dose of 40-80 mg daily.
    • Grape seed extract proanthocyanidin doses of 150-300 mg per day. Proanthocyanidin is one of the active ingredients in grape.
  • For reducing eye stress due to glare: Grape seed extract proanthocyanidin doses of 200-300 mg per day.

Safety Concerns

Grape is LIKELY SAFE when consumed in amounts commonly found in foods.

Grape is POSSIBLY SAFE when taken by mouth in medicinal amounts. Grape seed extracts have been used safely in studies for up to 14 weeks. Eating large quantities of grapes, dried grapes, raisins, or sultanas might cause diarrhea. Some people have allergic reactions to grapes and grape products. Some other potential side effects include stomach upset, indigestion, nausea, vomiting, cough, dry mouth, sore throat, infections, headache, and muscular problems.

Special precautions & warnings:

Pregnancy and breast-feeding: Not enough is known about the use of grape in medicinal amounts (supplements or amounts that are higher than normal food amounts) during pregnancy and breast-feeding. Stay on the safe side and avoid use.

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.

Interaction with medication

Moderate
Be cautious with this combination.
Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
Some medications are changed and broken down by the liver. Grape juice might increase how quickly the liver breaks down some medications. Taking grape along with some medications that are changed by the liver can decrease the effectiveness of these medications. Before taking grape, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include amitriptyline (Elavil), caffeine, chlordiazepoxide (Librium), clomipramine (Anafranil), clopidogrel (Plavix), clozapine (Clozaril), cyclobenzaprine (Flexaril), desipramine (Norpramin), diazepam (Valium), estradiol (Estrace, others), flutamide (Eulexin), fluvoxamine (Luvox), grepafloxacin (Raxar), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), mirtazapine (Remeron), naproxen (Naprosyn), nortriptyline (Pamelor), olanzapine (Zyprexa), ondansetron (Zofran), propafenone (Rythmol), propranolol (Inderal), riluzole (Rilutek), ropinirole (Requip), ropivacaine (Naropin), tacrine (Cognex), theophylline (Theo-Dur, others), verapamil (Calan, Covera-HS, others), warfarin (Coumadin), and zileuton (Zyflo).

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Grape might slow blood clotting. Taking grape along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, indomethacin (Indocin), ticlopidine (Ticlid), warfarin (Coumadin), and others.

Phenacetin
The body breaks down phenacetin to get rid of it. Drinking grape juice might increase how quickly the body breaks down phenacetin. Taking phenacetin along with grape juice might decrease the effectiveness of phenacetin.
Warfarin (Coumadin)
Warfarin (Coumadin) is used to slow blood clotting. Grape seed might also slow blood clotting. Taking grape seed along with warfarin (Coumadin) might increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
Minor
Be watchful with this combination.
Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)
Some medications are changed and broken down by the liver. Grape seed might decrease how quickly the liver breaks down some medications. Taking grape along with some medications that are changed by the liver might increase the effects and side effects of these medications. Before taking grape, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include amitriptyline (Elavil), diazepam (Valium), zileuton (Zyflo), celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), and others.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Some medications are changed and broken down by the liver. Grape seed might decrease how quickly the liver breaks down some medications. Taking grape along with some medications that are changed by the liver might increase the effects and side effects of these medications. Before taking grape, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and numerous others. Use grape cautiously or avoid in patients taking these drugs.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.