Acetaldehyde is a chemical compound naturally present in some foods and produced within the human body. It forms as a byproduct of various biological processes and environmental exposures. Its presence and how the body handles it have important implications for human health.
Where Acetaldehyde Comes From
A primary source of acetaldehyde in the body is alcohol metabolism. When alcohol is consumed, it is broken down in the liver by an enzyme called alcohol dehydrogenase (ADH), which converts it into acetaldehyde. Acetaldehyde also enters the body through various environmental exposures, such as tobacco smoke, vehicle exhaust, and air pollution. Additionally, it is naturally present in some foods and beverages, including fermented products like yogurt, cheese, and bread, and in ripe fruits such as oranges, bananas, strawberries, and apples.
How Your Body Handles Acetaldehyde
The body has a specific metabolic pathway to process and eliminate acetaldehyde, primarily within the liver. After alcohol dehydrogenase converts alcohol to acetaldehyde, aldehyde dehydrogenase (ALDH) plays a central role. ALDH quickly oxidizes acetaldehyde into acetate, a harmless compound that is then excreted from the body. The ALDH2 enzyme is a key player in this detoxification process, acting predominantly in liver cells. Genetic variations in the ALDH2 gene can affect the enzyme’s efficiency. For instance, ALDH2 deficiency, common in people of East Asian descent, results in a less effective or inactive ALDH2 enzyme. This deficiency leads to a buildup of acetaldehyde after alcohol consumption, causing symptoms like facial flushing, rapid heart rate, and nausea, often called “alcohol flush syndrome.”
Acetaldehyde’s Effects on Your Health
Acetaldehyde is classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen. Its harmful effects stem from its high reactivity, allowing it to damage biological molecules. It can harm DNA and proteins, disrupting cellular function and contributing to inflammation. The accumulation of acetaldehyde is linked to an increased risk of several health issues. It raises the risk of certain cancers, particularly those of the head, neck, esophagus, and liver. High levels of acetaldehyde in saliva and the gastrointestinal tract following alcohol consumption contribute to this increased cancer risk, especially in individuals with impaired ALDH activity. Acetaldehyde also contributes to hangover symptoms like nausea, headaches, and vomiting. It is implicated in the progression of alcohol-related liver disease, which can lead to liver damage, fibrosis, and cirrhosis.