Red wine, in moderation, has long been thought of as heart healthy.
The alcohol and certain substances in red wine called antioxidants may help prevent heart disease by increasing levels of "good" cholesterol and protecting against artery damage.
While the news about red wine might sound great if you enjoy a glass of red wine with your evening meal, doctors are wary of encouraging anyone to start drinking alcohol.
That's because too much alcohol can have many harmful effects on your body.
Still, doctors do agree that something in red wine appears to help your heart, though it's unclear just exactly what that "something" is. Researchers think antioxidants, such as flavonoids or a substance called resveratrol, have promising heart-healthy benefits.
How is red wine heart healthy? The studies supporting red wine suggest antioxidants in red wine called polyphenols help protect the lining of blood vessels in your heart. These antioxidants come in two main forms: flavonoids and nonflavonoids.
Flavonoids - These antioxidants are found in a variety of foods, including oranges, grape juice, apples, onions, tea and cocoa.
Other types of alcohol, such as white wine and beer, contain small amounts, too, but red wine has higher levels.
Nonflavonoids - These antioxidants found in red wine have recently been of particular interest because they appear to help prevent arteries from becoming clogged with fatty blockages. Resveratrol is the nonflavonoid that's received the most attention from researchers.
Resveratrol might be a key ingredient in red wine that helps prevent damage to blood vessels, reduces "bad" cholesterol and prevents blood clots.
Some research shows that resveratrol could be linked to a reduced risk of inflammation and blood clotting, both of which can lead to heart disease.
More research is needed before it's known whether resveratrol was the cause for the reduced risk. Some companies sell supplements containing resveratrol. However, not enough is known about resveratrol's effects to endorse resveratrol supplements. Research into the potential heart-health benefits of resveratrol is continuing.
Resveratrol can be found in grapes and other foods. The resveratrol in red wine comes from the skin of grapes used to make wine.
Because red wine is fermented with grape skins longer than is white wine, red wine contains more resveratrol. Simply eating grapes, or drinking grape juice, has been suggested as one way to get resveratrol without drinking alcohol.
Some studies have suggested that red and purple grape juices have some of the same heart-healthy benefits of red wine. Other foods that contain some resveratrol include peanuts, blueberries and cranberries.
It's not yet known how beneficial eating grapes or other foods might be compared with drinking red wine when it comes to promoting heart health.
The amount of resveratrol in food and red wine can vary widely