Chapter 35 - Ethanol Metabolism and Implications for Disease

Abstract

Ethanol is one of the most commonly used recreational drugs worldwide, and “drinking” is synonymous with the consumption of beverages containing ethanol. Alcohol can damage almost every organ in the body and is responsible for 4% of the global burden of disease. On a geographical level, the burden of disease attributable to alcohol may be greater than that of either tobacco, communicable diseases, or noncommunicable diseases. The ethanol content of alcoholic beverages usually varies between 3% and 50% alcohol by volume, and in some cases can be higher. When alcoholic beverages are consumed, ethanol is absorbed from the gastrointestinal tract and rapidly distributed around the body in the blood before entering tissues, such as the brain. Acetaldehyde, which is produced by metabolism of ethanol in the stomach and liver, is toxic but is further oxidized to acetate. The metabolism of acetate and its significance are less understood, although it will be eventually oxidized in the Krebs cycle, thereby generating cellular energy. The relationships between ethanol metabolism, blood ethanol concentration, and the harmful effects of ethanol are complex and vary between individuals and with drinking habits. Many acute effects correlate with the peak blood ethanol concentrations (BEC) or peak BEC within organs during a drinking session. Other more chronic effects may be due to products of metabolism and the total dose of ethanol ingested over a period of time. The relevance of the absorption, distribution, and metabolism of ethanol to alcohol-induced disease is reviewed.