Alcohol's impact affected by genes, studies show

Oct 26 2011 - 11:31am

"I have taken more out of alcohol than alcohol has taken from me," Winston Churchill once observed.

And there's plenty of evidence that light to moderate alcohol consumption can have health benefits for many people but carries grave risks for others. The trick lies in figuring out just who falls in which pathway.

New research from a team of California researchers indicates that not only are individual responses to alcohol influenced by genetic differences, but that the brains of people who carry a trait that produces a low-level response to booze actually work differently from those who don't have the trait even when they're not drinking.

A low-level response to alcohol reflects at least partly a set of genes that result in the brain being more tolerant of booze. People with this trait have a significant risk of developing alcoholism.

The new findings are based on mental task studies carried out by subjects who were either low or high alcohol responders, after they drank either real or fake shots and while their brain activity was being monitored through functional magnetic resonance imaging.

The same group of researchers had found similar results using a different set of cognitive tests.

The differences "may help explain why low (response) subjects might have more problems recognizing the effects of moderate doses of alcohol," said Marc Schuckit, a professor of psychiatry at the University of California at San Diego, and a senior author of the study.

"If you aren't able to recognize the effects of lower doses of alcohol, you are more likely to drink heavy amounts per occasion, which both directly and indirectly increases your risk for alcohol problems."

A tool to assess alcohol risk in teens was recently released with guidelines from the National Institute on Alcohol Abuse and Alcoholism. Intended for use by pediatricians and other primary caregivers, the screening comes down to two questions, worded somewhat differently for elementary, middle and high school patients.

One asks if they have any friends who "drank beer, wine or any drink containing alcohol in the past year." The other asks how many days in the past year "have you had more than a few sips of beer, wine or any drink containing alcohol."

Based on the answers, clinicians can use a "risk estimator" chart that takes into account age and other factors to give a broad indication of whether their patient is at risk for alcohol-related problems.

Two other recent studies shift focus of the impact of alcohol on the immune system.

One study, at the University of Adelaide in Australia, worked with mice to determine that immune response in the brain at least partly governs how the brain reacts to alcohol.

Specifically, the researches found when they blocked an immune system element called toll-like receptors in the mice brain, either with a drug or genetically, the effects of alcohol on the animals was reduced. Dr. Mark Hutchinson, lead researcher for the project, said the findings could both help identify people prone to alcohol problems and offer a new approach to treating alcohol dependence and overdoses.

Another recent study on human cells, done at the University of Massachusetts Medical School, found that alcohol suppresses the ability of several immune system elements to fight off viral infections.

That impact had already been noted in the liver, but the new research focused on the impact on immune system-activating receptors in blood cells that had been given the equivalent of four or five drinks a day for seven days.

(Contact Lee Bowman at BowmanL@shns.com.)

 

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