The extract of grape seeds is used to treat a wide variety of health conditions. In addition to high blood pressure, some people use this extract to lower high cholesterol, and improve poor circulation and atherosclerosis, which is when the arteries become hardened and damaged. Although there are some possible side effects and more clinical research is needed, there is some evidence that grape seed extract does support blood vessel health.
The theory behind the effectiveness of this supplement lies in the high concentration of antioxidants grape seed extract contains. The type of antioxidant in grape seed extract is called proanthocyanidins. Antioxidants remove free radicals from the body that can damage the walls of blood vessels, ultimately leading to high blood pressure. The effectiveness in grape seed extract has been shown in animals, but more research is necessary to demonstrate this effectiveness in humans.
According to the University of Maryland Medical Center, the dosage used to prevent damage to the body from free radicals is taking 25 to 150 mg between one and three times each day. The NYU Langone Medical Center, however, cites a total daily dose of 150 to 300 mg, which is approximately the range recommended by the University of Maryland Medical Center. The dosages recommended are for standard type of extract that contains between 40 and 80 percent of the antioxidant proanthocyanidins.
Blood Pressure Warning
Even though people take this extract to lower high blood pressure, one of the possible side effects of taking this supplement is high blood pressure. This effect was especially seen in a study by Dr. N.C. Ward and colleagues published in the "Journal of Hypertension in 2005." Blood pressure rose further in patients who already had high blood pressure and took a combination of vitamin C and grape seed extract. Therefore, it is a good idea to check with your doctor about whether this extract would be right for you and exactly how to take it.
Other Possible Side Effects
Grape seed extract can also cause other side effects, but these are less serious than increasing the level of blood pressure that is already high. These side effects include an itchy, dry scalp, headache; dizziness and nausea; hives; and indigestion. Telling your doctor about all medications and supplements you take will help him or her give you the best medical advice.
- "Journal of Hypertension"; The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial; Ward NC et al.; February 2005
- University of Maryland Medical Center: Grape Seed
- National Center for Complementary and Alternative Medicine: Grape Seed Extract
- NYU Langone Medical Center: Oligomeric Proanthocyanidins (OPCs)