Teen Drinking Could Epigenetically Hinder Brain Development

Alcohol is likely the most used and abused substance in the world. It’s fine to have a few cocktails or beers per week, but only for those that are of the legal drinking age. Underage drinking is a consistent issue faced in the United States today.

According to the CDC, kids ages 12-20 consume about 11% of all alcohol in the US, and this can be problematic as it is often done in a bingeing manner, rather than a causal one. Alcohol intake can take its toll on a teenager in many forms, beyond the obvious intentional inebriation. Excessive drinking can lead to nausea, changes in behavior, black-outs, ethanol poisoning, and a whole slew of other issues.

In addition to these side effects, new research is finding that alcohol use at an early age may impact a person’s epigenetics, interfering with brain development and health. We already know from previous articles that drinking inhibits a gene’s ability to process cholesterol. As well, potential dads who drink could epigenetically influence their child’s affinity for and sensitivity to alcohol.

According to scientists at the University of Illinois at Chicago, binge drinking during adolescence may cause lifelong epigenetic changes in the emotional center of the brain. These changes could lay the groundwork for the development of anxiety, fear, stress, and other psychological issues.

In the study published in Translational Psychiatry, Dr. Subhash Pandey and his team studied the postmortem amygdala samples from 44 different subjects: 11 of whom began binge drinking before the age of 21; 11 who began drinking heavily after 21 years of age, and 22 who had no history of excessive alcohol use/abuse.

They focused their efforts on how teenage drinking can epigenetically alter a protein called brain-derived neurotrophic factor (BDNF), which is associated with the formation and proper function of synapses in the brain. As we’ve seen previously, BDNF gene expression can be increased as a result of exercising, which may help to improve memory and learning. However, in the case of teenage binge drinking, the opposite might be true.

The team discovered an increased presence of a large non-coding RNA called BDNF-AS in the adolescent heavy drinkers when compared to both the legal drinkers and the subjects with no history of alcohol abuse. While RNA is usually associated with producing proteins from DNA, in this case, it is not.

BDNF-AS has been found to inversely regulate the BDNF protein, so increased levels of BDNF-AS in a given area results in a lower concentration of BDNF, which could prove troublesome for the undeveloped teenaged brain.

“BDNF is needed for normal development in the brain and for connections to form between neurons,” said Dr. Pandey. “If levels are lowered due to alcohol exposure, then the brain will not develop normally.” These permanent changes could lead to issues with emotional processing, fear, and anxiety.

He and his team attribute the lower amounts of BDNF to decreased levels of RNA methylation to the BDNF-AS found in the early drinkers.

RNA methylation typically occurs at N6-methyladenosine (m6A) and 5-methylcytosine (5-mC), and both can affect the translation of mRNA, as well as silence gene expression. In this case, the reduced level of methylation to the BDNF-AS allowed the suppression of BDNF, potentially hindering the complete brain development of the teenage binge drinkers.

Brain development is at an extremely critical and vulnerable point during adolescence, making the findings in this study imperative in the eye of public health and alcohol education. Dr. Pandey highlighted the importance of the team’s discovery. “The epigenetic changes we saw in the amygdala of early-onset drinkers can alter the normal function of the amygdala, which helps regulate our emotions,” he said. “And, [this] may cause individuals to be more susceptible for things like anxiety, which we have shown in other studies, or the development and maintenance of alcohol use disorder later in life.”

Source: Pandey S et. al. (2019) The lncRNA BDNF-AS is an epigenetic regulator in the human amygdala in early onset alcohol use disorders Translational Psychiatry 9:34 

Reference: University of Illinois at Chicago “Heavy drinking in teens causes lasting changes in emotional center of brain.” UIC Today. Feb. 2019