How Heavy Drinking Damages the Brain

Chronic alcoholism typically takes a heavy toll on the brain. Exposed to years of heavy drinking, neurons may stop functioning properly and brain tissue can atrophy. In fact, chronic alcoholism is one of the leading causes of dementia, second only to Alzheimer’s disease.

In total, an estimated 50 to 75 percent of long-term alcoholics show cognitive impairment and structural damage to the brain as a result of their drinking. However, the way in which alcohol leads to brain degeneration is not fully understood.

A mini-review published in the journal Experimental Biology and Medicine explores the existing evidence, focusing on the potential role of DNA damage and issues with DNA repair.

Every day, cells work to repair damage to DNA caused by natural metabolic processes and environmental sources such as exposure to ultraviolet light and radiation. Repairing DNA is critical for cellular functioning, and accumulation of too much damage may cause the cell to die, go dormant, or divide uncontrollably, potentially resulting in a cancerous tumor.

Chronic heavy drinking is known to cause extensive DNA damage, which can result in “genomic instability”—a term for aberrant changes to the genetic makeup that put one at risk for a host of disorders, including cancer and neurodegeneration.

Accumulated DNA damage is thought to be an important factor underlying aging.

Therefore, defective DNA repair may cause the brain to age prematurely.

Studies also suggest that impairment to a key cellular process known as one-carbon metabolism is involved in alcohol-related brain damage. This biochemical process plays a critical role in creating DNA precursors, DNA repair, and DNA methylation, so dysfunction may cause genomic instability, leading neurons to work improperly or die.

By understanding the mechanisms that cause chronic alcohol abuse to damage the brain, scientists may one day be able to develop therapeutics that reduce or eliminate damage.

NIAAA spectrumVolume 5, Issue 1 | February 2013.
National Institutes of Health •
National Institute on Alcohol Abuse and Alcoholism.
http://www.spectrum.niaaa.nih.gov