Grapes: When In Doubt, Go Straight to the Source

Thanks to the Mediterranean diet and the French Paradox, we've heard a lot about red wine and heart benefits. Thanks to the dietary supplement industry, we've also heard a lot about grape seed extract. But what about grapes themselves? Aren't these delicious fruits the original source of all red wine

and all grape seed extracts? Researchers in the Evans Department of Medicine and the Whitaker Cardiovascular Institute at Boston University School of Medicine in Boston, MA have recently published a comprehensive review of studies in this area involving wine made from red grapes, extracts made from the seeds of red grapes, grape juice, and grapes themselves. As a first step in their review, these researchers point out that the appearance of one particular group of phytonutrients in grapes-polyphenols-appears to be a common thread running through all of the grape-related health studies. The three types of polyphenols that seem most important with respect to health benefits are: (1) flavonoids, (2) phenolic acids, and (3) resveratrol. Interestingly, all three types of polyphenols appear to be more concentrated in the skins, stems, and seeds of grapes than in the juice middle section of the fruit.

When grape juice is compared to orange juice and grapefruit juice, or when red wine is compared to white wine or beer, studies show that the grape juice and red wine provide a greater level of heart benefits. (These heart benefits include decreased risk of high blood pressure, decreased risk of high cholesterol, decreased cardiovascular disease, and decreased risk of death from cardiovascular disease.) In the case of red versus white wine, the authors reasoned that the skins, stems, and seeds of the red grapes stayed in contact with the final product for a much longer period of time and passed on their heart-protective polyphenols in this way. (It's also worth noting here that even though moderate alcohol intake has been shown to have some heart-supportive effects, the authors noted that alcohol by itself does not account for the extent of heart support provided by red wine. That conclusion is also underscored by the greater heart benefits provided by red versus white wine, even when their alcohol content is the same.) In the case of beer versus red wine, and in the case of grape juice versus grapefruit juice or orange juice, the researchers believed that key heart-protective polyphenols simply weren't present at the same levels as found in grapes.

As for the ability of polyphenols in red grapes to lower heart disease risk, these Boston University scientists were confident that at least two basic mechanisms were involved. First, the polyphenols helped protect blood vessel linings by functioning as antioxidants and anti-inflammatory substances. Second, they helped protect against unwanted blood vessel blockage by keeping function of the platelet cells in a healthy range.

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We really like the idea of going back to the source and recognizing grapes themselves-and especially their skins-as the origin of red wine's cardiovascular benefits. While red wine or supplements made from grape seeds may have health benefits, the best way to get all of the skin benefits is to eat the skins just like they found are on whole, fresh grapes!

Reference: Bok Choy