The so-called French paradox has fueled the notion that grapes and thus, red wine, may provide cardiovascular health benefits. The concept is based on the low death rate attributed to heart disease despite a diet that is high in cholesterol and saturated fats. These observations are a stark contrast to the recommendations presented in the "Dietary Guidelines for Americans, 2010." While the evidence is compelling, most studies involving grapes' cardiovascular benefits, including their effects on blood pressure, have involved animals rather than humans. If you have a pre-existing condition, ask your doctor if grapes may be appropriate for you.
Active Ingredients
Grapes contain a variety of antioxidants that may be responsible for the health benefits, particularly resveratrol and proanthocyanidins for heart health. The former is found primarily on the skin of grapes and the latter in the seeds. Antioxidants can help protect the body caused by free radicals. These unstable oxygen molecules can cause cell damage and have been linked to several conditions including heart disease and cancer.
Resveratrol
Resveratrol may help lower blood pressure from several fronts. A study published in the September 2002 issue of "Circulation," found that resveratrol enhanced nitric oxide formation in laboratory studies. Nitric oxide causes blood vessels to dilate and relax, thus reducing the pressure within them. Scientific evidence also suggests that resveratrol may act on another risk factor for high blood pressure. A study published in the January 2011 edition of "Annals of New York Academy of Science" found that resveratrol increased fat burn and inhibited fat formation. According to the "Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure," maintaining a healthy weight can lower blood pressure between 5 and 20 mmHg.
Proanthocyanidins
Proanthocyanidins found in grape seeds may also help lower blood pressure. A study published in the July 2010 edition of the "Molecular and Cellular Proteomics" found that grape seed proanthocyanidins inhibited the formation of fat in rats fed a high-fat diet. By slowing fat formation, this effect may lower the risk of atherosclerosis or hardening of the arteries. This condition negatively impacts blood vessels by narrowing the diameter within them and increasing pressure. The risk also exists that plaque formation can lead to deadly clots.
Guidelines for Use
While serious drug interactions have not been reported, you should consult your doctor before taking grapes or its active ingredients especially if you are currently taking medication for blood pressure. If these dietary supplements are effective, it can lead to unsafe drops in blood pressure. In addition, Drugs.com cautions against taking resveratrol if you are taking blood thinners such as aspirin or warfarin. As research continues, guidelines for using grapes and its heart-friendly ingredients will emerge, giving you a clearer idea how it may benefit you.
References
- "Heart"; The French Paradox: Lessons for Other Countries; J. Ferrières; January 2004
- USDA Center for Nutrition Policy and Promotion: Dietary Guidelines for Americans, 2010 - Foods and Food Components to Reduce
- "Journal of Cardiovascular Pharmacology"; Grapes, Wines, Resveratrol, and Heart Health; A. Bertelli and D, Das; December 2009
- "Annals of New York Academy of Sciences"; Effect of Resveratrol on Fat Mobilization; C. Baile, et al.; January 2011
- "Circulation"; Resveratrol, a Polyphenolic Phytoalexin Present in Red Wine, Enhances Expression and Activity of Endothelial Nitric Oxide Synthase; T. Wallerath, et al.; September 2002
- U.S. Department of Health and Human Services;Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; August 2004
