According to the Dietary Guidelines for Americans, 2010, moderate drinking is [1-p.31]:
- For men: 2 drinks per day or 14 drinks per week
- For women and adults after 65: 1 drink per day or 7 drinks per week
Possible Health Benefits of Moderate Drinking
- Reduced risk of coronary heart disease, heart attack and heart failure due to increased blood levels of HDL and decreased levels of LDL cholesterol and triglycerides, and decreased blood coagulation and thus clot formation [1-p.31; 3,4]. Drinking up to two drinks per day does not affect the blood pressure . It is still not clear if consuming red wine is more protective to the heart than consuming other alcohol beverages .
- Reduced risk of the hardening of the arteries (atherosclerosis) in the limbs, but only in non-smokers [1,2]. Alcohol dilates arteries, but not enough to significantly increase the blood flow through the already narrowed atherosclerotic arteries in the limbs .
- Reduced risk of obesity , diabetes type 2 [1,2] chronic atrophic gastritis caused by H. pylori (in individuals who drink less than four drinks per week) , gallstones [1,2], ischemic stroke (caused by a clogged brain artery) [1,2], osteoporosis in women after menopause , cognitive decline in old people and death 
- Reduced risk of kidney cancer, lymphoma and thyroid cancer . Long-term wine drinking may somewhat protect against esophageal, stomach and colorectal cancer . The protective effect of polyphenols quercetin, rutin and resveratrol in wine is uncertain, though.
- The sensitivity for the beneficial effects of moderated alcohol drinking is partly genetically determined .
Possible Harms of Moderate Drinking
- Increased risk of breast cancer . According to one estimation, each gram of alcohol per day increases the risk of breast cancer by 1%, possibly due to increased estrogen levels . Taking 400-600 mg of folate per day might reduce the risk of breast cancer in moderately drinking women [1,2].
- Progression to heavy drinking, especially in the persons with family history of alcoholism 
- Increased risk of nerve damage (peripheral neuropathy) in diabetics 
- Increase of the blood triglyceride levels in those who already have hypertriglyceridemia 
- Increased risk of reactivation of the inflammatory bowel disease (Crohn’s disease, ulcerative colitis) [12,13]
Heavy or High-Risk Drinking
Heavy or high risk drinking means :
- For men: 5 drinks or more at a single occasion or 15 drinks or more per week
- For women and adults after 65: 4 drinks or more at a single occasion or eight drinks or more per week. Women and adults after 65 tend to have less body water than men before 65, so they may achieve certain blood alcohol concentrations after fewer drinks than men before 65.
According to the National Institute on Alcohol Abuse and Alcoholism in the U.S., binge drinking is drinking that brings the blood alcohol concentration (BAC) to 0.08% (g/100 ml blood) or above , which may result, for example, from 3 drinks in an hour by a 140 lbs (65 kg) woman or 4 drinks in an hour by a 160 lbs (73 kg) man .
Dangers of Binge Drinking
- Increased risk of irregular heart rhythm (arrhythmia) . Heart rhythm disturbances after the weekend drinking are known as “holiday heart syndrome” .
- Sudden increase of blood pressure 
- Chest pain (in individuals with heart-related chest pain) due to a coronary artery spasm several hours after consumption (often in the morning) 
- Increased risk of sudden cardiac death 
- Hypoglycemia or alcoholic ketoacidosis, especially in individuals who have not eaten for few days, or in diabetics taking insulin or glucose-lowering drugs [11,19]
- Adolescent who engage in binge drinking are at increased risk to become alcoholics .
- Binge alcohol drinking inhibits the synthesis of proteins and may thus reduce the muscle-growing (anabolic) effect of protein intake and exercise .
- Dietary Guidelines for Americans, 2010
- Alcohol: Balancing Risks and Benefits Harvard T.H. Chan
- Hein HO et al, 1997, Alcohol consumption, S-LDL-cholesterol and risk of ischemic heart disease. 6-year follow-up in The Copenhagen Male Study PubMed
- Spaak J et al, 2008, Dose-related effects of red wine and alcohol on hemodynamics, sympathetic nerve activity, and arterial diameter PubMed
- Gillespie JA, 1967, Vasodilator Properties of Alcohol PubMed Central
- Arif AA et al, 2005, Patterns of alcohol drinking and its association with obesity: data from the third national health and nutrition examination survey, 1988–1994 PubMed Central
- Gao GL, 2009, Alcohol consumption and chronic atrophic gastritis: population-based study among 9,444 older adults from Germany PubMed
- Sampson HW, 1998, Alcohol’s Harmful Effects on Bone National Institute on Alcohol Abuse and Alcoholism
- Lee JE et al, 2007, Alcohol intake and renal cell cancer in a pooled analysis of 12 prospective studies PubMed
- Stockley CS, 2003, Recent research about alcohol and colorectal cancer Aim-digest.com
- Emanuele NV, 1998, Consequences of Alcohol Use in Diabetes National Institute on Alcohol Abuse and Alcoholism
- Ginsberg H et al, Moderate Ethanol Ingestion and Plasma Triglyceride Levels: A Study in Normal and Hypertriglyceridemic Persons Annals of Internal Medicine
- Swanson GR et al, 2011, Is moderate red wine consumption safe in inactive inflammatory bowel disease? PubMed
- NIAAA Newsletter, December, 2004 National Institute on Alcohol Abuse and Alcoholism
- 2003, Alcohol Problems in Intimate Relationships: Identification and Intervention National Institute on Alcohol Abuse and Alcoholism
- Budzikowski AS, Holiday Heart Syndrome Emedicine
- High blood pressure (hypertension) Mayo Clinic
- Panos RJ et al, 1988, Sudden death associated with alcohol consumption PubMed
- Alcohol ketoacidosis Emedicine
- Crabbe JC et al, 2011, Preclinical studies of alcohol binge drinking PubMed
- Matsuguchi T et al, 1984, Provocation of variant angina by alcohol ingestion PubMed