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.
Children and fetuses are especially at risk. Alcohol consumption during pregnancy can result in fetal alcohol spectrum disorders (FASDs), a range of lifelong physical, behavioral, and intellectual disabilities. In response to these risks, some countries now require alcohol packaging warning messages that mention cancer risks and pregnancy dangers.
Although some studies have proposed potential health benefits of light alcohol consumption—such as reduced risk of cardiovascular disease, type 2 diabetes, gastritis, and cholelithiasis— experts, including the World Health Organization (WHO), have questioned the validity of these studies, and say these possible benefits are small and uncertain when weighed against the well-known risks, especially cancer. While alcohol may provide short term effects of temporary stress reduction, mood elevation, or increased sociability, experts emphasize that, in the long run, the significant and cumulative health consequences of alcohol use outweigh these perceived psychosocial benefits.
Overall effect
The level of ethanol consumption that minimizes the risk of disease, injury, and death is subject to some controversy. Several studies have found a J-shaped relationship between alcohol consumption and health, meaning that risk is minimized at a certain (non-zero) consumption level, and drinking below or above this level increases risk, with the risk level of drinking a large amount of alcohol greater than the risk level of abstinence. Other studies have found a dose-response relationship, with lifetime abstention from alcohol being the optimal strategy and more consumption incurring more risk. The studies use different data sets and statistical techniques so they cannot be directly compared. Some older studies included former and occasional drinkers in the "abstainers" category, which obscures the benefits of lifetime abstention as former drinkers often are in poor health. However, the J-curve was reconfirmed by studies that took the mentioned confounders into account. Nonetheless, some authors remain suspicious that the apparent health benefits of light alcohol use are in large part due to various selection biases and competing risks. Mendelian randomization studies have been inconsistent regarding the risk curve, with three studies finding linear dose-response risks overall and two studies finding a J-shape for lipid profiles. The variance in alcohol consumption that is explained by genetics is small, requiring large sample sizes and potentially violating assumptions of the analysis.
As one reviewer noted, "Despite the wealth of observational data, it is not absolutely clear that alcohol reduces risk, because no randomized controlled trials have been performed." The National Institute on Alcohol Abuse and Alcoholism (NIAAA) announced a randomized controlled trial in 2017, but the National Institutes of Health (NIH) cancelled it in 2018 due to irregular interactions by the program staff with the alcohol industry. A trial in Spain is expected to complete in 2028.
In 2013, Norwegian psychiatrist Hans Olav Fekjær compared the situation to those of hormone replacement therapy (HRT), vitamin E, and β-carotene; similarly to alcohol, observational studies for each of these treatments showed significantly reduced risk of coronary heart disease, but initial randomized trials of these treatments failed to replicate the effect. For HRT, pooling multiple randomized control trials and stratifying the data by age and time since menopause showed the benefits were limited to treatment soon after menopause. For vitamin E, trials have shown that the benefits are limited to certain populations such as those with diabetes and a specific genotype. For β-carotene, the randomized trials have shown that β-carotene increases cardiovascular disease risk when supplemented, with all beneficial effects due to other vitamins in foods providing β-carotene.
In light of the conflicting evidence, many have cautioned against recommendations for the use of alcohol for health benefits. At a symposium in 1997, Dr. Peter Anderson of the World Health Organization (WHO) labeled such alcohol promotion as "ridiculous and dangerous". It has been argued that the health benefits from alcohol have been exaggerated by the alcohol industry, with industry participation in the wording of messages and warnings. The debate is not purely scientific, with groups such as the International Scientific Forum on Alcohol Research (ISFAR) critiquing anti-alcohol studies as distorting the evidence, scientists in turn accusing these groups of bias due to industry funding, and members of the groups responding that these are false and misleading assertions. Studies with industry funding find less risk of stroke, and industry-linked systematic reviews consistently find cardioprotective effects, compared to reviews with no associations being 54% positive.
Considered as a treatment for cardiovascular disease, alcohol is addictive, has greater risk of adverse effects, and is less effective than other interventions such as heart medications, exercise, or good nutrition.
The world
The available evidence is in agreement that current drinking levels are too high. The WHO has emphasized the need to revise alcohol control policies worldwide in order to reduce overall alcohol consumption.
Globally, assuming the J-shaped curve is correct, the age-standardised, both-sexes consumption that minimizes risk is about 5 grams of ethanol per day, and an average individual would cause themselves harm by drinking more than 17 grams per day. However, the average intake among current drinkers in 2016 was approximately 40 grams of ethanol per day. 1.03 billion males (35.1% of the male population aged ≥15 years, ~2/3 of male drinkers) and 312 million females (10.5% of the female population aged ≥15 years, ~1/3 of female drinkers) consumed harmful amounts of alcohol. The proportion of the population consuming harmful amounts of alcohol has stayed at approximately the same level over the past three decades.
Estimates of the worldwide number of deaths per year caused by alcohol vary. The 2016 Global Burden of Disease (GBD) study estimated 2.8 million, while the 2020 GBD study estimated 1.78 million. The WHO estimates 3 million deaths per year from harmful use of alcohol, representing 5.3% of all deaths across the globe. All of these numbers are net deaths, subtracting deaths prevented from deaths caused. Professor Tim Stockwell, former director of the Canadian Institute for Substance Use Research argues that alcohol may not prevent any deaths and guesses that as many as 6 million deaths may be caused by alcohol. Besides this, the WHO attributes 5.1% of the global burden of disease and injury to alcohol, as measured in disability-adjusted life years (DALYs). The WHO does not list alcohol in its 2019 list of the top 20 leading causes of DALYs, but alcohol use disorder (AUD) would rank around #39, combining AUD with alcohol-related cirrhosis and liver cancer would rank between malaria (#19) and refractive errors (#20), and all alcohol-attributed DALYs would rank between stroke (#3) and lower respiratory infections (#4). Similarly the number of alcohol-attributed deaths would rank between chronic obstructive pulmonary disease (#3) and lower respiratory infections (#4).
Research of Western cultures has consistently shown increased survival associated with light to moderate alcohol consumption.Di Castelnuovo A, Costanzo S, Bagnardi V, Donati MB, Iacoviello L, de Gaetano G. Alcohol dosing and total mortality in men and women: an updated meta-analysis of 34 prospective studies. Arch Intern Med. 2006 Dec 11–25;166(22) 2437-45. Australasia and Europe are also the locations with the highest levels of harmful alcohol consumption. Researchers have investigated cultures with different alcohol consumption norms and found conflicting results.
The risks of alcohol consumption are age-dependent. Risk is greatest among males aged 15–39 years, due to binge drinking which may result in violence or traffic accidents. It is less risky and potentially more beneficial for an older individual to consume a given amount of alcohol, compared to a similar younger individual, as they are less likely to develop cancer during their remaining lifespan, less likely to be involved in accidents, and more likely to benefit from alcohol's cardiovascular effects. Taking the lower bound of the confidence intervals, the GBD 2020 study suggests that people do not need to drink until age 25, and in many regions, the study did not find any significant benefit for drinking over abstinence even as late as ages 45 or 60. Other studies have found similar patterns.
India A study of 4,465 subjects in India confirmed the association of alcohol consumption with coronary risk in men. Compared to lifetime abstainers, alcohol users had higher blood sugar (2 mg/dl), blood pressure (2 mm Hg) levels, and high-density lipoprotein cholesterol (HDL-C) levels (2 mg/dl) and significantly higher tobacco use (63% vs. 21%). Indians who consume alcohol had a 60% higher risk of heart attack, which was greater with local spirits (80%) than branded spirits (50%). The harm was observed in alcohol users classified as occasional as well as regular light, moderate, and heavy consumers. Five percent of all cancers diagnosed in Indians in 2021 were attributed to alcohol consumption, with cancers of the esophagus, liver, and breast accounting for the most number of cases.
Russia