Researchers based at University College London have put forward the latest food for thought on wine and health. They found that drinking alcohol, even in low amounts, might be associated with higher cognitive ability, especially for women.
Their study, published in the Aug. 1 issue of the American Journal of Epidemiology, found that people who consume anywhere from one drink a week up to 30 drinks a week performed better than nondrinkers on a battery of different tests designed to measure their intellectual ability. "Compared with abstainers, persons drinking one or two glasses of alcohol per day had a significantly lower risk of poor cognitive function," the authors wrote.
Subjects who drank alcohol occasionally, but who did not drink in the week prior to the tests, also performed better than nondrinkers, but they did not do as well as the people who drank regularly. "In terms of cognitive function, we found that frequent drinking may be more beneficial than drinking only on special occasions," the authors wrote.
It was not clear if the benefits were due to the alcohol itself, or if other factors may have had an impact on the volunteers' mental skills. The researchers noted that drinkers tended to earn more and have higher levels of education than nondrinkers. "Moderate consumption could be a proxy marker for good mental and physical health and for high socioeconomic position, both of which are related to good cognitive performance," the authors wrote. They added, "Alternatively, alcohol may have a causal effect via improved vascular function, which is itself associated with good cognitive ability in the general population."
Prior studies that examined whether alcohol consumption affects cerebral skills have yielded inconsistent results or dealt with elderly populations, according to the team, which was led by Michael Marmot, a professor of epidemiology and public health at the college.
For this study, the team wished to see if the amount and frequency of alcohol consumption could impact the mental processes of a somewhat younger population, aged 46 to 68. To do so, they pulled data from the larger, long-running Whitehall II Study, which investigated the relationship between socioeconomic status and health in more than 10,000 civil servants in London. That study, which is still ongoing, started in 1985, when the participants were 35 to 55 years old.
The Whitehall Study participants are asked to document their alcohol consumption, physical activity and smoking habits. During each stage of the research, participants undergo physical exams, with blood samples and blood pressure levels taken. In the late 1990s, myriad cognitive tests were administered to the volunteers.
Those tests were aimed to provide a well-rounded picture of each volunteer's mental abilities. For instance, one test on "verbal fluency" required each participant to write down, within one minute, as many animals as they could think of that begin with the letter "s." Another tested "inductive reasoning" by asking people to "identify patterns and infer principles and rules" in a series of verbal and mathematical items with a gradually increasing level of difficulty.
Marmot's research analyzed data on 6,033 Whitehall participants who completed all the exams and who did not change their drinking habits over the course of the study. The team examined the volunteers' drinking habits over the course of a year and categorized the civil servants according to their levels of alcohol consumption in the week prior to reporting their drinking patterns: never, none in the past week, one to 80 grams, 81 to 160 grams, 161 to 240 grams and 241 grams or more. (According to the scientists, a typical glass of wine or shot of liquor has 8 grams of alcohol, while the standard serving size for beer in London, a pint, has 16 grams.)
The team then compared the participants' test results with their drinking habits. Across the board, drinkers performed better on all of the tests compared with nondrinkers and with the people who reported not drinking in the previous week. (The research team did not break down the results according to beverage preference. An earlier Danish study found that, on average, wine drinkers tend to be smarter than beer drinkers and nondrinkers.)
In most of the tests, women performed better than their male counterparts in the same consumption categories; for instance, in the "inductive reasoning" test, women performed 10 percent to 30 percent better than men. The scientists think that this could be due to women choosing different types of alcohol than men do. Or they speculated that women might metabolize alcohol in a gender-specific way, based on differing stomach enzymes or body fat-to-water ratio, which may lead to a possible cognitive improvement. "Unfortunately, we were unable to look at these effects with our data," the authors wrote.
In most of the tests, the results improved the more the subjects drank in a week. Overall, the heaviest drinkers -- men who drank more than 241 grams of alcohol per week -- typically performed 10 percent to 30 percent better than other drinkers. However, on one of the vocabulary tests, volunteers who consumed 81 to 160 grams per week outperformed the heaviest drinkers, as well as those in all the other categories.
The scientists discounted the inference that the heaviest drinkers are better thinkers, noting that very few civil servants reported drinking more than 241 grams per week. Further, "the benefits of alcohol drinking [at this level] may be outweighed by an increased risk of diseases and of violence and accidents," they wrote.
Additionally, the authors cautioned that their findings should not be used to encourage alcohol consumption.
For a comprehensive look at the potential health benefits of drinking wine, check out senior editor Per-Henrik Mansson's feature Eat Well, Drink Wisely, Live Longer: The Science Behind A Healthy Life With Wine
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