Natural Products

Grape Seed

Vitis vinifera

Efficacy

• Indications with proven efficacy:
  None
• Indications with possible, but poorly documented efficacy - the use of this product cannot be recommended:
  Chronic venous insufficiency
  Decreasing ocular stress from glare
• Also used for these other indications, but with no proof of efficacy:
  Allergic rhinitis
  Cardiovascular protection
  Hemorrhoids
  Improving night vision
  Improving wound healing
  Skin aging

Security

• Risk of Drug Interactions: Low
• Adverse Effects: Rare

What is it?

Grape vine has been cultivated since the dawn of time. Today, it is found in all temperate climates around the globe. Grape seed oil is rich in essential fatty acids and vitamin E.

Oligo-proanthocyanidins (OPC) are potent antioxidant compounds. OPCs are found in the grape seed's envelope and are responsible for the pharmacological effects. Several standardized extract supplements are currently available on the market.

Warning

In 2004, Canada adopted new regulations that control the manufacturing, packaging, labeling and importing of natural health products. The new regulations also include an adverse reaction reporting system. Products that conform to the regulation's criteria are identified with a natural product number (NPN) or homeopathic medicine number (DIN-HM) and can be legally sold in Canada. This number indicates that the product meets specific criteria for safety and purity, not that it is effective for any indication.

Medicinal plants content varies naturally from plant to plant – just as fruits from the same package may vary in taste and texture. There is no standard to measure the active content of each plant. Thus, efficacy of natural products should be expected to vary from brand to brand as well as from bottle to bottle of the same brand.

For more information about the Natural Health Products Regulations, or to check if a product has been assessed, visit the Health Canada website at http://www.hc-sc.gc.ca/dhp-mps/prodnatur/index-eng.php.

Does it work?

There is no evidence that grape seed extract is effective in any indication. However, it is used to treat certain medical conditions where it may be of some benefits:

• Decreasing ocular stress from glare:
  Several small clinical studies have shown that OPCs may be effective to protect against ocular glare (200 mg to 300 mg of grape seed extract daily).
• Chronic venous insufficiency:
  Grape seed extract may help relieve leg pain and tumefaction caused by venous insufficiency and varicose veins. Take 150 mg to 300 mg of OPC-standardized grape seed extract daily.

There is insufficient reliable information to conclude that grape seed extract is effective in any other indication.

Is it safe?

• Grape seed is not associated with any specific toxicity and there has been no report of adverse effects.
• Since there is no safety data available concerning its use during pregnancy and breast-feeding, pregnant and lactating women should not take grape seed extract.
• Grape seed extract may interact with oral anticoagulants, such as Coumadin, and increase the effects of antiplatelet agents. Bleeding risks may be increased.

Clinical notes

• OPC has interesting properties, but available information is insufficient to conclude to its efficacy. The product may be extracted from grape seed, peanut skins and pine bark (Pycnogenol).

References

1. Natural Medicines Comprehensive Database, Therapeutic Research Faculty, 2007
2. Passeportsanté.net. Vigne rouge. http://www.passeportsante.net
3. Herbal Companion to AHFS DI, American Society of Health-System Pharmacists, 2001
4. Taylor J. CE: Phytomedicinals: Uses, precautions, and drug interactions. Drug Topics 2003;1:79