The liver: One of the most amazing organs. It’s the only visceral organ in the human body capable of completely regenerating itself, even after up to 90% has been injured, damaged, or removed [1].

Liver regeneration is the process by which the liver replaces lost tissue by growth from remaining tissue. The kind of regeneration the human liver undergoes is in size, also called compensatory hyperplasia, due to the proliferation of cells or increase in cell division [2][3][4]. This is different from liver regeneration in other organisms, such as zebrafish, where the liver regenerates in not just size but also shape [5].

Some have argued that the human liver’s regenerative abilities were known thousands of years ago by the ancient Greeks. In the Myth of Prometheus, Zeus punishes Prometheus by chaining him to a rock and ordering an eagle to fly by each day and eat part of his liver. Since his liver would regenerate each night, he was meant to endure this punishment for eternity [6]. In the Myth of Tityus, Tityus also receives the same punishment [7].

While the human liver has the ability to regenerate, it’s not invincible. If the liver is repeatedly damaged, it’ll try to repair itself by forming scar tissue. This is called liver fibrosis [8]. When the scar tissue becomes pervasive, it destroys the liver’s structure so it can no longer regenerate or function [9]. Extensive scarring is called cirrhosis of the liver [10]. The damage caused by cirrhosis is irreversible and can be fatal. In cases of severe cirrhosis, the only chance of survival is being put on a long list for a liver transplant, and the number of people who need liver exceed the number of donors there are [11][12].

One common cause of cirrhosis of the liver is alcoholic liver disease [13][14]. What does it take to put oneself at risk of alcoholic liver disease? Years of “heavy alcohol use,” which is defined for men as consuming more than 4 drinks on any day or more than 14 drinks per week, for women as consuming more than 3 drinks on any day or more than 7 drinks per week, or for anyone as binge drinking on five or more days in any given month [15][16]. To put 14 drinks in perspective, that’s 2 beers a night. Likewise, 7 drinks a week could mean a glass of wine a night. While many are aware that "heavy drinking" may increase one’s risk of alcoholic liver disease, it’s unfortunate that not everyone knows regularly consuming a seemingly small amount of alcohol can still be considered heavy alcohol use.

The liver is an amazing organ. Someone in my life is dying of cirrhosis of the liver caused by alcoholic liver disease, and I wonder if it could’ve been prevented. Please take care of yours.