Gene helps alcohol help the heart

From Philadelphia, at the annual meeting of the American Society of Human Genetics

A daily alcoholic drink and the right genes is one prescription for a healthy heart, suggests a new study. This finding builds upon previous research indicating that moderate consumption of alcoholic beverages reduces a person’s risk of developing heart disease or suffering a heart attack, notes study coauthor Lisa M. Hines of the Harvard School of Public Health in Boston.

Some investigators attribute this cardiac protection directly to alcohol. But others suggest that the protection stems from compounds called flavonoids, which are abundant in red wines, beer, and dark liquors, or from lifestyle factors associated with moderate alcohol consumption.

Hines’ group studied the influence of the gene that encodes alcohol dehydrogenase 3. That’s the enzyme that begins the breakdown of ethanol, the type of alcohol in most drinks. This gene has two versions, one whose enzyme metabolizes alcohol faster than the other’s does.

If the presence of alcohol was the key to cardiac health, Hines and her colleagues theorized, people with two copies of the gene making the slow ethanol-clearing enzyme would have less heart disease than those so-called fast metabolizers, who have two copies for the fast enzyme.

To test their theory, the investigators turned to the Physicians’ Health Study, which has followed a large group of male doctors since 1982. Hines’ team examined the alcohol dehydrogenase genes of 396 men in that study who had suffered a heart attack and 770 others who hadn’t.

Among the physicians who averaged a drink a day, men with a double dose of the slow-enzyme gene had a 30 percent reduction in heart attack risk compared with the fast metabolizers.

“This is evidence that it’s ethanol” protecting the heart, says Hines. Exactly how alcohol safeguards the heart remains a matter of debate, but the new study lends support to the idea that it works by raising the amount of high-density lipoprotein (HDL), the so-called good cholesterol, in the blood. Among moderate drinkers, the slow metabolizers had higher HDL concentrations than the fast metabolizers had, reports Hines. Men with one copy of each gene had HDL concentrations in between, she adds. A similar link between the dehydrogenase gene and HDL was seen in 325 postmenopausal women, notes Hines.

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