Study Identifies Alcohol Associated Gene

Feb. 22, 2001 -- Scientists have identified a gene that may help explain why moderate drinking can ward off heart attacks.

The researchers found that a variant of the gene makes the bodybreak down alcohol very slowly. That slow breakdown, in turn,appears to raise levels of heart-protecting "good cholesterol" inthe blood.

Moderate drinkers with the gene variant were found to have asharply lower risk of heart attack than those whose bodies dispensewith alcohol more quickly, according to researchers at the HarvardSchool of Public Health and Brigham and Women's Hospital.

Moderate alcohol consumption has long been known to ward offheart disease, but the latest research shows the influence of thisone genetic variation.

The gene produces enzymes called alcohol dehydrogenase thatbreak down alcohol. The gene comes in two forms: One metabolizesalcohol quickly, the other slowly. People inherit one copy of thegene from each parent, so they can end up with two genes that makethe fast-working enzymes, two that make the slow enzymes, or one ofeach.

People with two copies of the slow gene — about one-sixth ofwhites — take 2½ times longer to break down alcohol than those withtwo copies of the fast gene, said Lisa M. Hines, a Harvard doctoralstudent. The slow gene is very rare in minorities, she said.

The study examined 396 male doctors who had suffered a heartattack, and 770 who had not.

Those who had two slow genes and averaged at least one drink perday had about an 85 percent lower risk of heart attack than the menwho had two fast genes and rarely drank.

When the researchers adjusted for level of alcohol consumptionand other factors, such as whether the doctors smoked, wereoverweight or had a history of heart disease, they still foundabout a 35 percent lower risk of heart attack in the men with twoslow genes.

The researchers theorize that keeping alcohol in the body longerthan normal raises levels of HDL, or good cholesterol.