Red wine is often touted for its heart-healthy benefits, but purple grape juice may also have heart benefits. Both red wine and purple grape juice contain several types of antioxidants. Antioxidants reduce cell damage by destroying molecules called free radicals and by preventing oxidative stress. Drinking purple grape juice may provide heart benefits to people who don't drink alcohol for personal reasons or for other health reasons. More human studies on the benefits of red grape juice compared to red wine are necessary.
Flavonoids
Flavonoids found in grapes and other fruits and vegetables may have antioxidant properties, but may also change signaling pathways within cells that direct cell growth or death. These changes can protect against both heart disease and cancer. The flavonoids found in purple grapes include anthocyanidins, catechins and proanthocyanidins.
Resveratrol
Resveratrol, a polyphenol, or type of plant chemical, prevalent in purple grape juice as well as red wine, has antioxidant properties when used in the laboratory. But eating or drinking products containing purple grape juice may produce lower levels of resveratrol than are found when you eat foods containing other well-known antioxidants, such as vitamins C and E. Cellular levels of resveratrol much higher than those found after people eat grapes have been used in most laboratory studies. Resveratrol also breaks down into metabolites after being eaten, which may not have the same antioxidant activity.
Studies
A report of several animal and human studies by researchers at the University of Wisconsin Medical Center, published in the 2002 issue of "Advances in Experimental Medicine and Biology," suggests that 5 to 10 ml of purple grape juice per kg of body weight daily could reduce platelet clotting, which can lead to blood clot formation in arteries that reduces blood flow to the heart. Purple grape juice also increased production of nitric oxide, which lowers blood pressure by relaxing blood vessels and also lowers low-density cholesterol, or LDL, the "bad" type of cholesterol.
Considerations
Countries such as France, where red wine consumption is high and heart disease low despite the prevalence of saturated fat in the diet, appear to derive a protective heart effect from red wine. But whether the benefit comes from the alcohol alone or if the antioxidants in purple or red grapes also contribute to heart disease reduction isn't yet clear. Moderate alcohol intake of one to two drinks per day does reduce the risk of heart disease by 20 to 30 percent, according to the Linus Pauling Institute. Including purple grape juice as part of your five to seven recommended servings of fruits and vegetables per day is a prudent choice, although the juice doesn't contain the fiber found in the grapes themselves.
References
- MayoClinic.com: Grape Juice: Same Heart Benefits As Wine?; Martha Grogan, M.D.; July 2009
- "Advances in Experimental Medicine and Biology"; Potential Health Benefits From the Flavonoids in Grape Products on Vascular Disease; J. Folts; 2002
- Linus Pauling Institute: Flavonoids; Victoria Drake, Ph.D.; June 2008
- Linus Pauling Institute: Resveratrol; Jane Higdon, Ph.D.; March 2005
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