Heavy alcohol use may slow brain growth

A new study has revealed that heavy use of alcohol among adolescents and young adults can actually slow the rate of growth in developing brains.

The research, carried out in nonhuman primates, has been published in the journal eNeuro.

The study shows that heavy alcohol use reduced the rate of brain growth by 0.25 millilitres per year for every gram of alcohol consumed per kilogram of body weight.

In human terms, it is equivalent to four beers per day. The research involved rhesus macaque monkeys at the Oregon National Primate Research Center.

"Chronic alcohol self-intoxication reduced the growth rate of the brain, cerebral white matter, and subcortical thalamus," the researchers wrote.

Researchers measured brain growth through magnetic resonance imaging of 71 rhesus macaques that voluntarily consumed ethanol or beverage alcohol.

Scientists precisely measured intake, diet, daily schedules, and health care, thus ruling out other factors that tend to confound results in observational studies involving people.

The findings of the study help validate previous research examining the effect of alcohol use on brain development in people.

"Human studies are based on self-reporting of underage drinkers," said co-author Christopher Kroenke. "Our measures pinpoint alcohol drinking with the impaired brain growth."

The new study is the first to characterise normal brain growth of one millilitre per 1.87 years in rhesus macaques in late adolescence and early adulthood.

And it further reveals a decrease in the volume of distinct brain areas due to voluntary consumption of ethanol.

Lead author Tatiana Shnitko said that previous research has shown the brain has a capacity to recover at least in part following the cessation of alcohol intake.

However, it's not clear whether there would be long-term effects on mental functions as the adolescent and young adult brain ends its growth phase. The next stage of research will explore that question.

"This is the age range when the brain is being fine-tuned to fit adult responsibilities," Shnitko said.