Sockeye red/Craig Medred photo

Once more science brings confusing news as to alcohol’s role in society.

Vilified by some as “demon rum,” hailed by others as the explanation as to why the French stay slim and healthy despite eating so much fatty food, chronicled repeatedly as the most abused drug in Alaska and studied as an apparent aid to creativity, the Dr. Jeklly and Mr. Hyde of commonly consumed substances is now being linked to improved brain health in middle age and older Americans.

After studying a group of 19,887 people for close to a decade, researchers from the University of Georgia, California State University and the Capital Medical Univerity in Bejing, concluded that low to moderate drinking slowed the normal cognitive decline that comes with age.

Their peer-reviewed study was published last week by JAMA Neurology.  JAMA is the journal of the American Medical Association.

The study’s authors freely admitted the two-faced nature of drink, noting that “alcohol misuse is a leading cause of morbidity and mortality. Alcohol consumption is associated with a uniformly increased risk of hypertension and stroke, regardless of dose, and heavy and binge drinking is associated with a higher risk of cardiovascular disease.

“However, studies have also found that low to moderate alcohol consumption is associated with protective effects against cardiovascular diseases. Besides its role in physical health, low to moderate alcohol consumption has been shown to play a role in the development of cognitive impairment and dementia, conditions that are highly associated with cardiovascular diseases, although the findings are mixed.”

Some previous studies have linked heavy drinking directly to dementia. The latest study suggests the effects are dose-related.

Some drinking is good; too much drinking is bad.

Moderation

“In the present study, although low to moderate drinking was associated with better cognitive functions and slower rates of cognitive decline, the associations between the weekly drinking dose and the various cognitive functions were U-shaped,” the researchers observed. “The optimal alcohol dosage associated with better cognitive function was 10 to 14 drinks per week for all participants” although there were gender differences.

The researchers suggested a limit of – on average – a drink per day for women and two drinks per day for men. They also reported some interesting break points on that U-shaped curve.

“The (average) weekly drinking dose at the turning points were 12 drinks for the total cognition score, 13 drinks for mental status, 10 drinks for word recall, and 14 drinks for vocabulary,” the study said.

The authors openly warned against heavy drinking, which is a problem for some seniors.

“Although the majority of drinkers in the Health and Retirement Study were low to moderate drinkers,” the researchers reported, “15 percent of white men, 4.9 percent of white women, 15.7 percent of black men, and 5.6 percent of black women had more than 14 drinks per week.

“Public health campaigns are still needed to further reduce alcohol drinking in middle-aged or older US adults, particularly among men.”

For reasons that are unclear, the study also found alcohol consumption more protective for white drinkers than for black drinkers, and there were some obvious limitations to the study starting with the self-reporting of consumption.

That, the authors admitted, “could introduce recall bias that classifies heavy drinkers as low to moderate drinkers because participants tend to underestimate their alcohol consumption.”

Very few people in the study reported consumption levels putting them in the heavy drinking category. But even if a significant number were downsizing their drinking habits, the authors said, the data remained “sufficiently robust” to document “significant associations between alcohol consumption and cognitive function.”

The researchers conceded potentially bigger confounders in the study were the fact “alcohol consumption tended to change with time,” which could influence outcomes, and a notable reduction of the influence of alcohol on brain function “among participants with no chronic disease.”

Among the healthiest participants in the study, they said, “the U-shaped associations were significant only for word recall and vocabulary, not for mental status and total cognitive score.”

The healthy participants did, however, start the study with “higher cognitive function scores and might be engaged in more social activities and have higher alcohol consumption leading to the higher cognitive function scores,” the researchers noted.

More than 77 percent of the participants in the study suffered from at least one chronic disease. The average age was 61.

Other studies have shown that both general fitness and social/intellectual activities help older people slow the cognitive decline associated with aging.

In the case of exercise, the simple explanation has been that cardiorespiratory fitness helps to improve the flow of oxygen to the brain which brings with it all sorts of benefits.

What alcohol does to foster improvements is unclear, but the researchers suggested the pathways might be similar to exercise.

“The main hypotheses focus on cerebrovascular and cardiovascular pathways…,” they wrote. “Several studies have found that low to moderate alcohol consumption is associated with better cardiovascular functions, fewer cardiac events, and longer survival compared with abstainers and heavy drinkers; thus, the decreased risk of cognitive impairment has been thought to be associated with alcohol consumption.”

There again, however, there is the issue of dosing.

“A recent study found that alcohol consumption increases the risk of hypertension and stroke regardless of dose, which decreases the likelihood of this potential mechanism,” the researchers wrote. “The role of alcohol drinking in cognitive function may be a balance of its beneficial and harmful effects on the cardiovascular system. Among low to moderate drinkers, the beneficial effects may outweigh the harmful effects on the cardiovascular system.”

The study offered no advice on the combined benefits of various, brain-protective activities, but it could be read to indicate that for senior runners, cyclists, skiers, paddlers and others engaged in regular physical exercise, stopping by the local brewpub with the gang to have a beer and debate the issues of the day might not be a bad way to end a workout.