Alcohol Good for You? Some Scientists Doubt It
By now, it is a familiar litany. Study after study suggests that alcohol in moderation may promote heart health and even ward off diabetes and dementia. The evidence is so plentiful that some experts consider moderate drinking — about one drink a day for women, about two for men — a central component of a healthy lifestyle.
But what if it’s all a big mistake?
For some scientists, the question will not go away. No study, these critics say, has ever proved a causal relationship between moderate drinking and lower risk of death — only that the two often go together. It may be that moderate drinking is just something healthy people tend to do, not something that makes people healthy.Maybe healthy people drink moderately, but moderate drinking may not make people healthy. Click To Tweet
“The moderate drinkers tend to do everything right — they exercise, they don’t smoke, they eat right and they drink moderately,” said Kaye Middleton Fillmore, a retired sociologist from the University of California, San Francisco, who has criticized the research. “It’s very hard to disentangle all of that, and that’s a real problem.”
Some researchers say they are haunted by the mistakes made in studies about hormone replacement therapy, which was widely prescribed for years on the basis of observational studies similar to the kind done on alcohol. Questions have also been raised about the financial relationships that have sprung up between the alcoholic beverage industry and many academic centers, which have accepted industry money to pay for research, train students and promote their findings.
“The bottom line is there has not been a single study done on moderate alcohol consumption and mortality outcomes that is a ‘gold standard’ kind of study — the kind of randomized controlled clinical trial that we would be required to have in order to approve a new pharmaceutical agent in this country,” said Dr. Tim Naimi, an epidemiologist with the Centers for Disease Control and Prevention.
Even avid supporters of moderate drinking temper their recommendations with warnings about the dangers of alcohol, which has been tied to breast cancer and can lead to accidents even when consumed in small amounts, and is linked with liver disease, cancers, heart damage and strokes when consumed in larger amounts.Even supporters of moderate drinking talk of the dangers of alcohol. Click To Tweet
“It’s very difficult to form a single-bullet message because one size doesn’t fit all here, and the public health message has to be very conservative,” said Dr. Arthur L. Klatsky, a cardiologist in Oakland, Calif., who wrote a landmark study in the early 1970s finding that members of the Kaiser Permanente health care plan who drank in moderation were less likely to be hospitalized for heart attacks than abstainers. (He has since received research grants financed by an alcohol industry foundation, though he notes that at least one of his studies found that alcohol increased the risk of hypertension.)
“People who would not be able to stop at one to two drinks a day shouldn’t drink, and people with liver disease shouldn’t drink,” Dr. Klatsky said. On the other hand, “the man in his 50s or 60s who has a heart attack and decides to go clean and gives up his glass of wine at night — that person is better off being a moderate drinker.”
Health organizations have phrased their recommendations gingerly. The American Heart Association says people should not start drinking to protect themselves from heart disease. The 2005 United States dietary guidelines say that “alcohol may have beneficial effects when consumed in moderation.”
The association was first made in the early 20th century. In 1924, a Johns Hopkins biologist, Raymond Pearl, published a graph with a U-shaped curve, its tall strands on either side representing the higher death rates of heavy drinkers and nondrinkers; in the middle were moderate drinkers, with the lowest rates. Dozens of other observational studies have replicated the findings, particularly with respect to heart disease.
“With the exception of smoking and lung cancer, this is probably the most established association in the field of nutrition,” said Eric Rimm, an associate professor of epidemiology and nutrition at the Harvard School of Public Health. “There are probably at least 100 studies by now, and the number grows on a monthly basis. That’s what makes it so unique.”
Alcohol is believed to reduce coronary disease because it has been found to increase the “good” HDL cholesterol and have anticlotting effects. Other benefits have been suggested, too. A small study in China found that cognitively impaired elderly patients who drank in moderation did not deteriorate as quickly as abstainers. A report from the Framingham Offspring Study found that moderate drinkers had greater mineral density in their hipbones than nondrinkers. Researchers have reported that light drinkers are less likely than abstainers to develop diabetes, and that those with Type 2 diabetes who drink lightly are less likely to develop coronary heart disease.Studies comparing moderate drinkers with abstainers have come under fire in recent years. Click To Tweet
But the studies comparing moderate drinkers with abstainers have come under fire in recent years. Critics ask: Who are these abstainers? Why do they avoid alcohol? Is there something that makes them more susceptible to heart disease?
Some researchers suspect the abstainer group may include “sick quitters,” people who stopped drinking because they already had heart disease. People also tend to cut down on drinking as they age, which would make the average abstainer older — and presumably more susceptible to disease — than the average light drinker.
In 2006, shortly after Dr. Fillmore and her colleagues published a critical analysis saying a vast majority of the alcohol studies they reviewed were flawed, Dr. R. Curtis Ellison, a Boston University physician who has championed the benefits of alcohol, hosted a conference on the subject. A summary of the conference, published a year later, said scientists had reached a “consensus” that moderate drinking “has been shown to have predominantly beneficial effects on health.”
The meeting, like much of Dr. Ellison’s work, was partly financed by industry grants. And the summary was written by him and Marjana Martinic, a senior vice president for the International Center for Alcohol Policies, a nonprofit group supported by the industry. The center paid for tens of thousands of copies of the summary, which were included as free inserts in two medical journals, The American Journal of Medicine and The American Journal of Cardiology.
In an interview, Dr. Ellison said his relationship with the industry did not influence his work, adding, “No one would look at our critiques if we didn’t present a balanced view.”
Dr. Fillmore and the co-authors of her analysis posted an online commentary saying the summary had glossed over some of the deep divisions that polarized the debate at the conference. “We also dispute Ellison and Martinic’s conclusions that more frequent drinking is the strongest predictor of health benefits,” they wrote.
(Dr. Fillmore has received support from the Alcohol Education and Rehabilitation Foundation of Australia, a nonprofit group that works to prevent alcohol and substance abuse.)
Dr. Ellison said Dr. Fillmore’s analysis ignored newer studies that corrected the methodological errors of earlier work. “She threw out the baby with the bathwater,” he said.