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The French Paradox – the observation that despite high-fat diets, French people seemed less prone to heart disease than their American counterparts – debuted in 1991.

The phrase gained fame when it was featured in a segment on "60 Minutes," which credited the paradox to red wine consumption. Highlighting the work of French researcher Serge Renaud, the program declared the link between red wine consumption and low rates of heart disease “all but confirmed.” After the program, news outlets reported that red wine sales in the U.S. shot up 44 percent in one month.

A lot has been learned since 1991, however.

Renaud reported his results in the scientific sphere in a 1992 article in the journal the Lancet. According to his findings, red wine inhibits platelet activity, preventing deadly clots from building up along artery walls. Epidemiological studies, Renaud reported, found that moderate red wine consumption could reduce the risk of coronary heart disease by “at least” 40 percent.

Other studies concurred, but all had one thing in common: They were all correlational, meaning researchers compared separate groups of people with different alcohol consumption habits. Despite attempts to control for outside variables (like weight or smoking) that could affect the results, the researchers couldn’t be sure that the decrease in heart disease risk was caused by wine consumption.

Perhaps people at less risk for heart disease preferred to drink moderately. Or perhaps a third variable explained both moderate drinking and low heart disease risk.

The last possibility got a boost in 2010, when French researchers published a study in Nature that examined the drinking habits of 149,773 people. They found that moderate wine consumption was associated with a number of factors that lower heart disease risk: lower rates of obesity, lower “bad” cholesterol levels and higher levels of “good” cholesterol, and lower blood pressure, among others.

But the wine itself didn’t seem responsible for these factors, the authors found.

Instead, moderate drinkers had higher social status and better health than either nondrinkers or heavy drinkers. That suggests, the researchers wrote, that drinking in moderation is something healthy people do, not something that makes people healthy.

The study doesn’t disprove the connection between wine and heart health, and other studies have boosted wine’s claim. Resveratrol, a compound found in red wine, seems to increase longevity in mice, according to a 2008 study in the journal Cell Metabolism. But no one knows if these benefits would apply to humans. (A study this week also indicates resveratrol combats obesity.)

For now, the best strategy for heart health may not be to measure out doses of wine like medicine, but to focus on healthy eating, exercise and social connections  with a glass of pinot for good measure.

 This article was provided by Life's Little Mysteries, a sister site to LiveScience.