Observational studies suggest a correlation between low to moderate alcohol consumption and cardiovascular protective effects.[3][4] Several studies and meta-analyses have shown a reduction in overall mortality among light to moderate alcohol drinkers compared to lifetime abstainers.[5][6] A statement from The Lancet in 2022, based on the 2020 Global Burden of Disease Study, noted that for adults over 40 consuming small amounts of alcohol may reduce risks for cardiovascular disease, stroke, and diabetes.[7]
Even light to moderate alcohol consumption can have negative effects on health,[8][9][10] such as by increasing a person's risk of developing several cancers.[11][12] A 2014 World Health Organization report found that harmful alcohol consumption caused about 3.3 million deaths annually worldwide.[13] Negative effects are related to the amount consumed with no safe lower limit seen.[14] Some nations have introduced alcohol packaging warning messages that inform consumers about alcohol and cancer, as well as fetal alcohol syndrome.[15] There are several potential ways for light alcohol drinkers to reduce their cancer risk. Research suggests that dietary intake of folate, in amounts commonly found in daily multivitamins, may help protect women from the increased risk of breast cancer associated with light alcohol consumption.[16] Additionally, two large U.S.-based studies on health professionals found no increased cancer risk from light to moderate alcohol consumption in men who do not smoke.[17][18] Some observational studies suggest a potential association between alcohol consumption and a decreased risk of certain cancers, such as kidney cancer, thyroid cancer, and non-Hodgkin lymphoma.[19][20][21][22] Multiple prospective studies suggest a protective effect of light to moderate alcohol consumption on cardiovascular health for both men and women.[23] Several mechanisms have been proposed to explain this association.[24][25][26] Additionally, alcohol may reduce the risk of clot formation, which can contribute to heart attacks and strokes, and lower the risk of developing diabetes.[27][28][29] A 2022 statement from The Lancet, based on the 2020 Global Burden of Disease Study, noted that the health risks associated with alcohol consumption for adults over 40 vary by age and region. For this age group, consuming small amounts of alcohol may reduce the risk of cardiovascular disease, stroke, and diabetes.[30]
The median lethal dose of alcohol in test animals is a blood alcohol content of 0.45%. This is about six times the level of ordinary intoxication (0.08%), but vomiting or unconsciousness may occur much sooner in people who have a low tolerance for alcohol.[31] The high tolerance of chronic heavy drinkers may allow some of them to remain conscious at levels above 0.40%, although serious health hazards are incurred at this level.
Alcohol also limits the production of vasopressin (antidiuretic hormone) from the hypothalamus and the secretion of this hormone from the posterior pituitary gland. This is what causes severe dehydration when alcohol is consumed in large amounts. It also causes a high concentration of water in the urine and vomit, and the intense thirst that goes along with a hangover.
^Cheryl Platzman Weinstock (8 November 2017). "Alcohol Consumption Increases Risk of Breast and Other Cancers, Doctors Say". Scientific American. Retrieved 13 November 2018. The ASCO statement, published in the Journal of Clinical Oncology, cautions that while the greatest risks are seen with heavy long-term use, even low alcohol consumption (defined as less than one drink per day) or moderate consumption (up to two drinks per day for men, and one drink per day for women because they absorb and metabolize it differently) can increase cancer risk. Among women, light drinkers have a four percent increased risk of[breast cancer, while moderate drinkers have a 23 percent increased risk of the disease.
^Noelle K. LoConte; Abenaa M. Brewster; Judith S. Kaur; Janette K. Merrill; Anthony J. Alberg (7 November 2017). "Alcohol and Cancer: A Statement of the American Society of Clinical Oncology". Journal of Clinical Oncology. 36 (1). Clearly, the greatest cancer risks are concentrated in the heavy and moderate drinker categories. Nevertheless, some cancer risk persists even at low levels of consumption. A meta-analysis that focused solely on cancer risks associated with drinking one drink or fewer per day observed that this level of alcohol consumption was still associated with some elevated risk for squamous cell carcinoma of the esophagus (sRR, 1.30; 95% CI, 1.09 to 1.56), oropharyngeal cancer (sRR, 1.17; 95% CI, 1.06 to 1.29), and breast cancer (sRR, 1.05; 95% CI, 1.02 to 1.08), but no discernable associations were seen for cancers of the colorectum, larynx, and liver.
^Allen, Naomi E., Valerie Beral, Delphine Casabonne, Sau Wan Kan, Gillian K. Reeves, Anna Brown, and Jane Green. "Moderate alcohol intake and cancer incidence in women." Journal of the National Cancer Institute 101, no. 5 (2009): 296-305.
^Kenechukwu Mezue, Michael T. Osborne, Shady Abohashem, Hadil Zureigat, Charbel Gharios, Simran S. Grewal, Azar Radfar, Alexander Cardeiro, Taimur Abbasi, Karmel W. Choi, Zahi A. Fayad, Jordan W. Smoller, Rachel Rosovsky, Lisa Shin, Roger Pitman, and Ahmed Tawakol. "Reduced stress-related neural network activity mediates the effect of alcohol on cardiovascular risk." Journal of the American College of Cardiology 81, no. 24 (2023): 2315-2325.
^Meyer, Jerold S. and Linda F. Quenzer. Psychopharmacology: Drugs, the Brain, and Behavior. Sinauer Associates, Inc.: Sunderland, Massachusetts. 2005. Page 228.