Wine May Protect Heart but Genes Determine How Much, Study Finds
Drinking wine in moderation may protect against heart attack--but how much depends on our genes, scientists have found.
The gene in question, according to researchers at the Harvard School of Public Health and Boston’s Brigham and Women’s Hospital, influences how the body breaks down alcohol. Moderate drinkers who inherit one version of the gene receive considerable protection against heart attacks; those who inherit a different version of that gene get much less protection. The study will be published in today’s New England Journal of Medicine.
The finding underscores that the consequences of our actions depend to some extent on our genetic makeup. It also strengthens the contention that the alcohol in wine--and not some other chemical--is what helps protect against heart disease.
But heart experts caution that the study should not encourage people to start drinking.
Alcohol, even in moderate amounts, confers risks as well as benefits. And the same gene that increases the positive effect of drinking wine might increase the downsides.
“There are other, [safer] things that are proven to help--lowering cholesterol, lowering blood pressure and exercise,” said Dr. Ira Goldberg, chief of the division of preventive medicine and nutrition at Columbia University and a past member of the American Heart Assn.’s nutrition committee.
The study used data from more than 22,000 physicians whose lives and health have been tracked since 1982. None of the doctors had been diagnosed with heart problems at the start of the study, but over the years some did suffer heart attacks.
As in other studies, the researchers found that people who reported drinking moderately (defined as 1-2 drinks daily) were about 40% less likely to have had heart attacks. This implies that moderate drinking may somehow protect the heart.
But the scientists also studied a gene known as ADH3, using blood samples that were collected at the start of the study. The gene controls production of an enzyme that removes the ethanol in beer and wine from our systems.
Every person has two copies of this gene--one inherited from each parent. But the gene comes in different forms. One form causes ethanol to be quickly removed; another form causes it to be removed more slowly.
When graduate student Lisa Hines and coauthors compared the DNA of 396 men who had heart attacks with that of 770 similar men who hadn’t, they found that moderate drinkers with two “slow-acting” genes had a 77% lower risk for heart attacks than those with two “fast-acting” genes.
Levels of HDL cholesterol--so-called good cholesterol that is thought to protect against heart disease--were also higher in the blood samples of people who had two “slow-acting” genes.
About 16% of white Americans have two of the slow-acting genes, Hines said. The number is much lower in African Americans and Asians.
Though many studies have suggested that moderate alcohol consumption might protect against heart disease, cause and effect has not been proved. It always is possible that something else about a moderate drinker’s lifestyle or some other chemical in the beverage (such as an antioxidant) is responsible.
“But this really suggests that the alcohol itself is the factor that’s important,” said Aldons Lusis, a human geneticist at UCLA who studies heart disease. The finding, he said, still needs to be reconfirmed in other experiments.
The scientists suggest that the reason that slow-acting genes lower heart disease risk could be that the alcohol--whatever it is doing to help the heart--has longer to do it.
If so, that could mean that the alcohol has a chance to cause more damage, cautions Goldberg. Alcohol consumption raises risk for stroke, high blood pressure and certain cancers, as well as damaging the liver and pancreas. There is also the risk of substance abuse.
Telling people to drink, he said, is not a good idea.
“This is an important study because it’s one of the earliest studies linking heart disease to genetic factors,” said Goldberg. “But for public health I don’t think it has major implications. . . . Populations that drink a lot of alcohol don’t live longer necessarily. They may have less heart disease, but there are other things that can get you.”
Studies like this--on how genes interplay with lifestyles--will be more common, now that the structure of the human genome has been figured out, said Dr. Ronald Krauss, former chairman of the American Heart Assn.’s nutrition committee and a senior scientist at the Lawrence Berkeley Laboratory. This could lead to more individualized interventions by doctors, using diets as well as drugs.
