More than 5 million underage Americans report binge drinking at least once a month, according to the National Institute on Alcohol Abuse and Alcoholism.
Binge drinking is defined as consuming four or more drinks within two hours for women, and five or more drinks for men. In the U.S., the NIAAA says it is a “serious health problem” for underage drinkers and poses a range of risks and negative consequences from injury to death.
While the dangers posed to teens themselves are well-known, a recent study reveals that teens’ risky behavior could affect the brain function of their future children, potentially putting them at risk of developing mood disorders such as anxiety or depression.
Previous research has shown that teenage binge drinking resulted in long-term changes in the brain, including dysfunction of an individual's stress response, said AnnaDorothea Asimes, lead author of the study and a Ph.D. student at Loyola University Chicago.
Researchers posited that these changes could be passed on to future offspring. They were particularly interested in the impact teen binge drinking could have on an offspring's hypothalamus, a region of the brain that helps regulate stress response, sleep-wake cycle and metabolism, among other things.
To test this, researchers exposed adolescent rats to a couple bouts of binge drinking prior to mating them in adulthood. Since offspring inherent genetic information from both parents, researchers mated several different pairs of rats – only mothers exposed to alcohol, only fathers exposed to alcohol and both parents exposed to alcohol – to see how parental exposure to binge drinking would affect inheritance. Rats that were not exposed to alcohol were used as a control group.
Researchers found that teen binge drinking altered the on-off switches of multiple genes in the offspring's hypothalamus.
When genes are turned on, they instruct cells to make proteins, which control physical and behavioral traits. “The genes are not mutated, but there are differences in how the expression of those genes is controlled,” Asimes said.
The study found that the changes in gene expression were unique to parental pairs. Researchers also found that when both parents engaged in teenage binge drinking there were twice as many genetic changes than when only one parent engaged in that behavior.
Though the study was conducted with rats, it does have implications for humans because “the hypothalamus functions similarly in humans and rats,” Asimes said. “Rats also tend to handle or metabolize alcohol in a similar way to humans, so we think that our model mimics human drinking behavior.”
Given the study’s findings, Asimes says people should be cognizant that their actions have consequences. “The actions you take throughout your life get incorporated into your DNA and has the potential to impact your offspring,” she said.
Future studies will examine what those genetic changes mean in terms stress behavior, circadian rhythm and other functions regulated by the hypothalamus.
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