Researchers at the National Institute on Aging (NIA) have found that drinking light to moderate amounts of alcohol -- be it wine, beer or hard liquor -- may slow the stiffening of the arteries that occurs as a natural part of aging. The benefit was more than 20 percent in people over age 70.
The study, presented yesterday at the American Heart Association's Scientific Sessions 2001 conference in Anaheim, Calif., also found that neither abstaining nor excessive drinking has the same beneficial effect. "A little bit may be good, but too much may override it," says study co-author Dr. Jerome Fleg, staff cardiologist at the NIA's Gerontology Research Center in Baltimore. "Our findings follow other epidemiologic data that large amounts of alcohol actually increase blood pressure."Among other things, arterial stiffening causes systolic blood pressure to rise. More flexible arteries translate into better cardiovascular health in general and less mortality. "One of the consequences of aging is stiffening of the arteries, and this makes the heart work harder," says Thomas Johnson, professor of molecular behavioral genetics at the University of Colorado at Boulder.
The researchers are not sure why, or even if, alcohol is responsible for the beneficial effect. "Like all epidemiological studies, cause-and-effect is unclear, but in this case I think there's reason to suspect that it might be somewhat causal," says Johnson. "Alcohol is a mild toxicant. It's certainly bad at high doses, but when one consumes one or two drinks a day, there's abundant evidence that's associated with decreased mortality."
The underlying mechanisms are unknown. "It may be that alcohol has some dilating effects," says Fleg. "My hunch is that alcohol essentially keeps the cardiac system clean. It has modest scouring actions which help prevent the buildup of plaques," says Johnson. The effect was the same regardless of the source of the alcohol.
The researchers looked at 563 volunteers, aged 20 to 90, who participated in the Baltimore Longitudinal Study of Aging, a National Institutes of Health-sponsored survey that began in 1958. Researchers used ultrasound for two measurements of the participants' carotid (neck) arteries: the arterial stiffness index (the relationship between the artery's blood pressure and its dimensions) and intimal media thickness (the thickness of the innermost layers of an artery).
Participants also filled out questionnaires about how much beer, wine and hard liquor they consumed, and they were divided into four groups based on their responses: those who abstained; occasional drinkers (less than one unit a week); light-to-moderate drinkers (between one and 9.9 units a week), and heavy drinkers (10 or more units weekly). A unit was defined as one four- to five-ounce glass of wine, one 12-ounce beer or two ounces of hard liquor.
The beneficial effect of alcohol was greatest in older study participants. Light to moderate drinkers under age 50 had about 15 percent lower stiffness than teetotalers. In those over age 70, however, stiffness was almost 30 percent lower in those who were light to moderate drinkers. This difference is probably due to the fact that people under age 55 don't have stiff arteries to begin with, says Fleg. Older individuals already have experienced stiffening, so the effect of alcohol begins to be seen. Perhaps the older group also had a longer history of alcohol intake and therefore more time for the alcohol to have an impact, he says.
Other than the stiffness findings, after adjusting for other variables, no association was found between intimal media thickness and alcohol intake.
Fleg says the next step is to follow study participants over time to see if the results still hold true.
What To Do
If you don't drink, don't start. If you do drink, keep your consumption on the light side.