Downing a cocktail or other alcoholic drink at least three to four times a week appears to substantially cut a man’s risk of heart attack, Boston-area researchers reported in early January. Less than a week later, a U.S.-Canadian team of epidemiologists focusing on African Americans announced it had found no clear benefit to people drinking the same amount of alcohol per week. These reports joined other seemingly conflicting studies on the health impacts of alcohol that have emerged in the past few years.
Some research found that regular, moderate drinking not only helps preserve mental clarity in both young and elderly people but also increases blood-sugar control in people with diabetes. Other studies linked low but regular consumption of alcohol with an increased risk of certain cancers and a stunting of children exposed to alcohol in the womb. These subtle detrimental effects, of course, add onto the potentially catastrophic acute events caused by alcohol-impaired judgment.
With dozens of conflicting reports spilling out each year, is it any wonder that the public is confused about alcohol and health?
Yet, in probing the scores of published papers on alcohol’s impacts, researchers have begun to discern a few trends. Chief among them: Alcoholic beverages can offer large pharmacological benefits, especially to people at elevated risk of heart disease.
Various studies have begun unveiling why (SN: 1/5/02, p. 8: A glass of red may keep arteries loose).
In fact, argues Jürgen Rehm of the Centre for Addiction and Mental Health in Toronto, because alcohol’s benefits appear primarily from slowing the progression of chronic diseases that usually emerge in or after middle age, there seems to be little health justification for drinking alcohol before age 40.
Among older adults, however, benefits of moderate drinking “appear to be huge,” notes Tim Stockwell, director of the National Centre for Research into the Prevention of Drug Abuse at Curtin University of Technology in Perth, Australia. Data in his country indicate that among people who regularly down a few drinks a day, “there are approximately 6,500 lives saved each year by alcohol’s protective effects on cardiovascular disease.” Even factoring in alcohol-associated deaths from breast cancer and other malignancies, he says, “the net benefit for [moderate] drinking here appears to be about 5,000 lives a year.”
“Although I think alcohol can be part of a healthy lifestyle, it’s not a necessity,” says Eric B. Rimm of the Harvard School of Public Health in Boston. Moreover, he adds, one wouldn’t want to push abstainers to start drinking if they have cultural, religious, or other prohibitions against it–or an inability to hold their drinking to a few glasses per day. And drinking should never, he says, be portrayed as a substitute for exercise, eating a healthy diet, or giving up cigarettes as the best ways to stave off heart disease.
But among people who now drink occasionally, Rimm says, the accumulating evidence of alcohol’s potential benefits is “so overwhelming that there are probably many cases where some people should be told to drink a little more.”
Risks in abstaining
Alcohol is without question a poison. People die from binging, and many children enter the world with a retardation that traces to prenatal alcohol exposure. In fact, Rehm says, more than 60 diseases have been linked to excessive consumption of alcohol.
Although one might expect those risks to increase linearly with consumption, they don’t. Stockwell points to hundreds of studies showing that a little daily drinking is more healthful than either abstaining or drinking to excess.
Epidemiologists refer to this as alcohol’s “J-shape curve,” for the contour that the risk data take when plotted on a graph. That provocative contour emerged strongly in a new review of 35 studies on stroke performed by researchers at Tulane University in New Orleans. In the Feb. 5 Journal of the American Medical Association, Kristi Reynolds and her colleagues confirm “a J-shaped association between alcohol consumption and the relative risk of . . . ischemic stroke,” a disorder that traces to blockages in the brain’s blood vessels.
Two years ago, Rehm and his colleagues reported a J-shape curve for alcohol consumption and premature deaths from all causes in their 11-year study of 5,200 U.S. men and women.
Economists at Duke University in Durham, N.C., published data 2 years ago showing a J contour in alcohol’s impacts on disability claims. For 6 years, Jan Ostermann and Frank A. Sloan followed 12,650 people initially in their 50s or 60s. People drinking one or two drinks a day were least likely to report a disabling event, such as stroke or arthritis, “whereas abstainers generally were most likely to be disabled.”
No matter how many possibly confounding factors they investigated, Sloan says, “we could not make the effect go away.”
Rimm’s team also observed a disadvantage for abstainers in a new 12-year study of heart-disease risks in 38,000 male health professionals. Overall, the researchers report in the Jan. 9 New England Journal of Medicine, disease risk fell as the volume of regularly consumed alcohol rose.
A J-shape curve has emerged in alcohol’s effects on diabetes and also on cognition. Last spring, federal scientists at the Beltsville (Md.) Agricultural Research Center linked alcohol consumption directly to blood sugar and insulin benefits in a trial with 63 healthy postmenopausal women.
In one 8-week phase, the women drank orange juice laced with 15 grams of alcohol each night before bed; in another, they drank juice containing 30 grams a night, the equivalent of two drinks. To keep other aspects of the diet from affecting the parameters being measured, the scientists administered carefully controlled meals to every woman throughout the trial. Such costly, controlled-feeding trials represent the gold standard of nutritional studies.
In the May 15, 2002 Journal of the American Medical Association, David J. Baer and his colleagues report that the women’s insulin values, blood sugar, and cholesterol were healthiest during the two-drink-per-day regimen.
Although this trial used straight ethanol in juice, other studies have shown that certain pigmented compounds, called phenolics, that show up in beer and red wine can have their own healthful effects on people’s hearts and blood sugar.
Pierre-Louis Teissedre and his colleagues at the University of Montpellier, France, gave diabetic rats phenolics-enriched white wine for 6 weeks in amounts equivalent to a person’s intake of a half-liter per day. Afterward, the rats’ blood quashed oxidative reactions–a major cause of diabetes complications–as well as the blood of healthy rats did. The treated animals also showed slightly improved control of blood-sugar concentrations. The findings appear in the Jan. 1 Journal of Agricultural and Food Chemistry.
The researchers then further enriched the wine with phenolics to achieve what Teissedre describes as pharmacological doses. In just-completed tests, this doctored wine “corrected the diabetes” by bringing control of the animals’ blood sugar into a normal range, Teissedre reports.
One interesting observation: The antidiabetes effect diminished when the animals received phenolics without alcohol.
A clear J-shape curve is also showing up in studies of alcohol’s effects on cognition. For instance, a year ago, Dutch researchers found that moderate drinkers have a lower risk of Alzheimer’s disease and dementias than do abstainers or heavy drinkers (SN: 2/2/02, p. 67: Drink and thrive: Moderate alcohol use reduces dementia risk).
While that study was in the works, Constantine G. Lyketsos and his colleagues at Johns Hopkins University in Baltimore investigated effects of long-term drinking on reasoning, memory, decision making, and psychomotor speed in nearly 1,500 people.
Scores on the test used in the study typically drop about 1 point per decade during early adulthood and 2 to 3 points per decade for people in their 60s. But in the new 13-year study, both young and old adults who regularly drank outperformed abstainers of the same age.
The finding was particularly robust for women, the Johns Hopkins team reported in the Oct. 15, 2002 American Journal of Epidemiology. Nondrinking women declined a point more on the test during the study than did moderate, habitual drinkers. For perspective, Lyketsos notes, “people with Alzheimer’s disease tend to decline an average of 3 to 4 points on this scale every year, so a 1-point drop is not negligible.” In fact, he concludes, because even heavy drinkers outperformed teetotalers, “the findings suggest that maybe the worst thing you can do is not drink.”
Such statements trouble Nancy L. Day of the Western Psychiatric Institute and Clinic in Pittsburgh. Many women don’t know they’re carrying a child until well into their pregnancy, she notes, and her data indicate that “no amount of alcohol is healthy during pregnancy”–at least for the child.
Over the past couple decades, she and her colleagues have been measuring the growth and development since birth of 565 children from low-income, inner-city families. In the October 2002 Alcoholism: Experimental and Clinical Research, Day’s group reported that 14-year-old children who had been exposed in the womb to alcohol were–as they had been at birth–shorter and leaner than the offspring of women who eschewed alcohol during pregnancy. The finding was true even for the women who downed just one or two drinks per month during their first trimester–a finding that “blew us away,” Day told Science News.
By age 14, children of the lightest drinkers averaged 3 pounds less than nondrinkers’ children; offspring of the heaviest drinkers, 16 pounds less. Though smoking during pregnancy also yields smaller babies, those kids “usually catch up within the first year or so,” Day notes.
What concerns her most is that teenage children of drinkers had a smaller average head circumference–”a very crude measure of brain size”–than nondrinkers’ teens had. Indeed, her latest findings show that fetal-alcohol exposure correlated with subtle changes in information processing that could impair learning.
For adults, drinking alcohol has also been tied to cancer. Many analyses show a steadily increasing risk of breast cancer as the average daily consumption of alcohol increases. For example, one 1998 study found that alcohol equivalent to one drink a day increases the risk of breast cancer by about 9 percent.
Characteristics of drinking can have an effect, too. People who down a significant share of their alcohol outside of meals, for instance, face at least a 50 percent higher risk of cancer in the oral cavity, pharynx, and esophagus than do people who drink only at meals (http://www.sciencenews.org/
A growing number of studies are finding new risks from binge drinking, which is usually defined as downing five or more servings of alcohol in one day. Lyketsos and his colleagues found in their study that people who typically binged had more cognitive decline than did heavy, frequent drinkers consuming comparable volumes of alcohol.
Indeed, Rehm and Christopher T. Sempos of the University of Buffalo’s Department of Social and Preventive Medicine suspect that bingeing may account for the results of their team’s analysis of drinking and health in 2,000 African Americans.
They analyzed 19 years’ of dietary data for blacks in the National Health and Nutrition Examination Survey (NHANES). The epidemiologists compared alcohol consumption per week with death from any cause. In the January Alcoholism: Experimental and Clinical Research, they report that the data for the African-Americans didn’t follow the J curve, but risk of death “increased with increasing average consumption.”
Rehm and Sempos note that the survey asked only how many servings of alcohol people typically down in a week. If the answer was 10 to 14, for example, but that amount was consumed only over the weekend, that’s bingeing, Sempos says.
In fact, the researchers cite three studies since 1995 indicating that the African-American community has a higher proportion of abstainers and bingers than the white population does. Moreover, says Thomas K. Greenfield of the Alcohol Research Group in Berkeley, Calif., some studies have reported “that because of larger containers and higher-alcohol-content products marketed to African-Americans, surveys [like NHANES] may even underestimate the heavy quantities consumed by ethnic minorities.”
Fuzzy reporting of consumption patterns compromises data from most alcohol surveys, Rehm observes. That’s why many researchers would prefer data from experiments in which people drink alcohol only under researchers’ supervision.
Shela Gorinstein of the Hebrew University–Hadassah Medical School in Jerusalem says her team expects to begin just such a clinical trial soon. Some lucky recruits will get free beer for 10 years.
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