Moderate drinking may lengthen your life, while too much may shorten it, researchers from Italy report. Their conclusion is based on pooled data from 34 large studies involving more than one million people and 94,000 deaths.

According to the data, drinking a moderate amount of alcohol -- up to four drinks per day in men and two drinks per day in women -- reduces the risk of death from any cause by roughly 18 percent, the team reports in the Archives of Internal Medicine.

However, "things radically change" when consumption goes beyond these levels, study leader Dr. Augusto Di Castelnuovo, from Catholic University of Campobasso, said in a statement.

Men who have more than four drinks per day and women who have more than two drinks per day not only lose the protection that alcohol affords, but they increase their risk of death, the data indicate.

The reason why men are protected at up to four drinks per day, while women lose the protection after two glasses has to do with how men and women metabolize alcohol, researchers say. It's been shown that when men and women who drink the same amount of alcohol, women experience higher blood alcohol levels than men.

Therefore, women who consume more than two glasses of alcohol per day may be at increased risk for diseases of the liver and certain types of cancer.

"Our findings, while confirming the hazards of excess drinking, indicate potential windows of alcohol intake that may confer a net beneficial effect of moderate drinking, at least in terms of survival," the Italian team concludes.

"Heavy drinkers should be urged to cut their consumption, but people who already regularly consume low to moderate amounts of alcohol should be encouraged to continue," they add.

The manner in which alcohol is consumed also appears to be important, the researchers report. "Little amounts, preferably during meals, this appears to be the right way (to drink alcohol)," said Dr. Giovanni de Gaetano of Catholic University, another author on the study. "This is another feature of the Mediterranean diet, where alcohol, wine above all, is the ideal partner of a dinner or lunch, but that's all: the rest of the day must be absolutely alcohol-free."

"The message carried by scientific studies like ours is simple," Dr. de Gaetano continued. "Alcohol can be a respectful guest on our table, but it is good just when it goes with a healthy lifestyle, where moderation leads us toward a consumption inspired by quality not by quantity."