Grapeseed extract, which is derived from whole grape seeds, is a rich source of antioxidant compounds called polyphenols, which are responsible for most of its health benefits. One group of polyphenols found in grapeseed extract is oligomeric proanthocyanidin complexes, which help combat free radicals that might increase the risk of disease and illness, according to the University of Maryland Medical Center. Research indicates that grape seed extract might have beneficial effects on blood pressure. Consult your health care provider before taking grapeseed extract.
Mechanism
Grapeseed extract might reduce blood pressure by improving blood vessel function, according to a study conducted by lead author Marion Man-Ying Chan and colleagues from Temple University School of Medicine. They discovered that grape polyphenols enhance the production of nitric oxide, a gas molecule found in the lining of cells. Nitric oxide improves blood vessel function by relaxing and dilating blood vessels. This in turn increases blood flow and decreases blood pressure. Scientists reported their findings in the November 2000 issue of the journal "Biochemical Pharmacology."
Reduces Blood Pressure
Scientists at the University of California Davis investigated the effects of grapeseed extract on patients with metabolic syndrome, a group of factors that increase the risk for heart disease, including high blood pressure. Participants were randomly assigned to receive 150 or 300 mg of grapeseed extract or a placebo. Blood pressure was measured before and after treatment. At the end of the study, which was presented at the American Chemical Society meeting in March 2006, lead researcher C. Tissa Kappagoda and colleagues discovered that both grapeseed groups experienced decreases in blood pressure compared to the placebo group.
Caution
When trying to lower blood pressure with grapeseed extract, avoid combining it with vitamin C supplements. Lead author N.C. Ward and researchers from the University of Western Australia and West Australian Institute for Medical Research discovered that subjects consuming the combination of 1,000 mg of grapeseed extract and 500 to 1,000 mg of vitamin C experienced increases in blood pressure, according to research published in the February 2005 issue of the "Journal of Hypertension."
Side Effects and Interactions
Grapeseed extract is generally considered safe, but pregnant women and breastfeeding women should not take the supplement. In addition, grapeseed extract can interact with certain medications, including blood thinners, according to the University of Maryland Medical Center. Therefore, consult your health care provider before taking grapeseed extract, especially if you are taking medications.
References
- University of Maryland Medical Center: Grape Seed
- PubMed: Synergy between ethanol and grape polyphenols, quercetin, and resveratrol, in the inhibition of the inducible nitric oxide synthase pathway
- Science Daily: Study Shows Grape Seed Extract May Be Effective In Reducing Blood Pressure
- PubMed: The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial
