May 25, 2018
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Red wine, red grapes and resveratrol

By Georgia Clark-Albert, Special to the BDN

We’ve been hearing for some time that there are health benefits connected with drinking a glass of red wine. Do you know what the benefits are? Should you start drinking wine to lower your cholesterol and reduce your risk of the formation of blood clots? It is time to look at the facts regarding red wine and its impact on your heart.

The alcohol and certain substances in red wine called antioxidants may help prevent heart disease by increasing levels of “good” (HDL) cholesterol and reducing the formation of blood clots.

Additionally, moderate amounts of alcohol help prevent artery damage caused by high levels of low-density lipoprotein (LDL) cholesterol, the bad cholesterol.

If you are a person that enjoys a glass of red wine in the evening this news might sound great, but health professionals are leery of encouraging anyone to start drinking alcohol if they don’t do so already. That’s because alcohol can be addictive and can cause or worsen other health problems. However, research shows that there is something in red wine that appears to benefit ones heart. That substance, a flavonoid called resveratrol may be the item responsible for the heart-health benefits.

Scientists became interested in looking at the potential health benefits of resveratrol in 1992 when it was first reported in red wine, leading to the speculation that resveratrol might help explain the “French Paradox” (the observation that mortality from coronary heart disease is relatively low in France despite relatively high levels of dietary saturated fat intake and cigarette smoking).

Continued interested has been generated as reports on the potential for resveratrol to inhibit the development of cancer and extend lifespan in cell culture and animal models. Dr. Elenaor Rogan, a professor in research in cancer and allied diseases at the University of Nebraska Medical Center believes that resveratrol has the ability to prevent the first step that occurs when estrogen starts the process that leads to cancer by blocking the formation of the estrogen DNA adducts. She believes that down the road, this knowledge (and further research) could stop the whole progression that leads to breast cancer. Scientists know that many breast cancers are fueled by increased estrogen, which collects and reacts with DNA molecules to form adducts. Rogan and colleagues found that resveratrol was able to suppress the formation of these DNA adducts.

Researches experimented with up to 100 umols/L of resveratrol; the suppression of DNA adducts was seen with 10 umol/L. A glass of red wine contains between 9 and 28 umol/L of resveratrol.

Resveratrol is also found in grapes, grape juice, peanuts and berries including blueberries, bilberries and cranberries. In grapes, resveratrol is found only in the skins. The amount of resveratrol in grape skins varies with the grape, the geographic origin and exposure to fungal infection. The amount of fermentation time a wine spends in contact with grape skins is an important determinant of its resveratrol content. Consequently white and rose wines generally contain less resveratrol than red wines. Red or purple grape juice may also be good sources of resveratrol.

Neither the American Heart Association nor the National Heart, Lung and Blood Institute recommend that you start drinking alcohol just to prevent heart disease. Drinking too much alcohol increases your risk of high blood pressure, high triglycerides, liver damage, obesity, certain types of cancer, accidents and other problems. In addition, drinking too much alcohol regularly can cause cardiomyopathy — weakened heart muscle — causing symptoms of heart failure. If you already drink red wine, do so in moderation. Moderate drinking is defined as an average of two drinks a day for men and one drink a day for women. The limit for men is higher because men generally weigh more and have more of an enzyme that metabolizes alcohol than do women. A drink is defined as 12 ounces of beer, 5 ounces of wine or 1.5 ounces of 80-proof distilled spirits.

The total resveratrol content of some beverages and foods are listed in the tables below:

Beverage: Total resveratrol in a 5-oz glass (mg)

White wines: 0.01 – 0.27

Rose wines: 0.06 – 0.53

Red wines: 0.30 – 10.07

Red grape juice: 0.17 – 1.30


Peanuts (raw) 1 cup: 0.01 – 0.26

Peanuts (boiled) 1 cup: 0.32 – 1.28

Peanut butter 1 cup: 0.04 – 0.13

Red grapes 1 cup: 0.24 – 1.25

Georgia Clark-Albert is a registered dietitian and adjunct nutrition instructor at Eastern Maine Community College who lives in Athens. Read more of her columns and post questions at or email her at


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