The long-term effects of alcohol consumption on health are predominantly detrimental, with the severity and range of harms generally increasing with the cumulative amount of alcohol consumed over a lifetime. The extent of these effects varies depending on several factors, including the quantity and frequency of alcohol intake, as well as individual genetic and lifestyle factors. Alcohol is recognized as a direct cause of several diseases, including cancer. The International Agency for Research on Cancer (IARC) classifies alcohol as a Group 1 carcinogen, meaning it is capable of causing cancer in humans. Research shows a causal link between alcohol consumption and at least seven types of cancer, including cancers of the oropharynx (mouth and throat), esophagus, liver, colorectum, and female breast. The risk begins with any level of consumption and goes up with higher intake—even light or moderate drinking adds to the risk. No level of alcohol consumption has been identified as completely safe in terms of cancer risk. The biological mechanisms include the damage caused by acetaldehyde, a toxic byproduct of alcohol metabolism, which can alter DNA, and the generation of oxidative stress.
Beyond cancer, chronic and excessive alcohol use—as seen in alcohol use disorder—is capable of damaging nearly every part of the body. Such use is linked to alcoholic liver disease, which can progress to cirrhosis and chronic pancreatitis; various forms of cardiovascular disease, including hypertension, coronary heart disease, heart failure, and atrial fibrillation; and digestive conditions such as gastritis and stomach ulcers. Alcohol also interferes with how the body absorbs nutrients, which can lead to malnutrition. Long-term use can cause alcohol-related dementia and damage to the peripheral nervous system, leading to conditions like painful peripheral neuropathy. Drinkers are also more likely to get injured in accidents, including traffic accidents and falls, and may age faster.