“Positive health effects of alcohol are widely reported, yet the many others
pointing to its dangers are often ignored.” (Global Alcohol Policy Alliance 2001)
Alcohol is the world’s most commonly used drug. The subject of alcohol is controversial and no more so than when attempting to understand the risks or benefits of moderate drinking. Healthy adults drinking moderately (less than two drinks a day for men and one drink for women) appear to be at little to no risk of harm while some studies indicate these amounts provide a therapeutic benefit. However, understanding of the health effects of alcohol is limited and cultural norms may obscure perceived personal risk. Consumption that may be considered normal and harmless for one individual may be quite different for another. A survey by the Health Education Authority in Britain showed that more than 50% of people believed alcohol is good for health and 35% believed that everyone benefits (BBC News 1998). Around 25% of drinkers are oblivious to the fact they are drinking hazardously (Lee N 1999).
“There is no level of drinking that can be called safe for all people at all times.”
(Ministry of Health 2002)
The health effects of alcohol use and abuse on an individual are variable depending on factors such as pattern and duration of use, age, gender, socioeconomic status, health status and genes. Equally there are times when drinking even small amounts can be hazardous such as during pregnancy, while driving or when using medication. With such variability there is no universally safe amount let alone an agreed universal benefit. While it may still be unclear whether low levels of alcohol consumption provide specific disease protection, there is no dispute that heavy use of alcohol, above recommended drinking guidelines, is a significant cause of disease and disability. More than 60 negative health consequences are linked with alcohol consumption (Gutjahr et al 2001).
"It is known that alcohol consumption in excess can lead to increased risk in heart attacks, strokes and high blood pressure, but what is not known is the effect at light to moderate levels." (Thadhani 2002)
There is widespread publicity and a belief that alcohol provides a protection for the heart and cardiovascular system. However heavy drinking (greater than two drinks a day) is recognised as a leading preventable cause of cardiovascular disease (CVD) including cardiomyopathy (heart muscle degeneration), coronary artery disease, high blood pressure, dangerous heart rhythms and stroke (NIAAA 2000). A number of studies of middle-aged men suggest that, compared to those who abstained from drinking alcohol, those consuming one to two drinks daily had a lower risk of cardio-vascular disease (CVD) (NIAAA 2000). However many other studies find no correlation with moderate drinking when the history and lifestyle variables are measured appropriately (Tsubono et al 2001; Fillmore 2000; Hart et al 1999; Thakker 1998; Andreasson 1998). For example it is important to measure appropriately for previous drinking patterns in abstainers. A study of 7169 middle aged men indicates that ex-drinkers have a higher risk of cardiovascular disease and mortality and all cause mortality than lifetime abstainers, occasional and light drinkers (Shaper and Wannamethee 2000).
Some studies suggest that heavy drinking is not associated with heart failure but increases the odds of death from other illnesses (Walsh et al 2002). Regular light drinkers appear to be at a lower risk of heart disease but this is not associated with a lower risk for other mortality causes. Compared to other types of alcohol, light consumption of wine appears to be associated with a lower risk of all-cause mortality (Wannamethee and Shaper 1999). How much of these findings are due to alcohol and how much is due to other factors remains unclear.
“A large part but not all of the greater benefit seen in wine drinkers relative to other drinkers can be attributed to advantageous lifestyle characteristics.” (Wannamethee and Shaper 1999)
A Danish study found that, compared to beer and spirit drinkers, those who drank wine were more likely to be highly educated, have higher socioeconomic status and IQ and more socially well adjusted (Mortenen et al 2001). Light drinking may have a positive psychosocial benefit as well as being helpful in reducing anxiety and stress, which are associated with illness (Pittman 1995). Social relationships are important for overall wellbeing. Abstaining from alcohol in an alcohol consuming culture could lead to isolation that threatens social integration. Lifelong non-drinkers that are socially isolated may be at greater health risk (Andreasson 1998). Abstainers appear to be less likely to engage in preventive health care services or take other beneficial health measures than light to moderate drinkers (Green 2001).
“The evidence appears to indicate that while moderate drinking is not antithetical to a healthy lifestyle, it is not an essential ingredient of one.” (Pittman 1995)
Alcohol consumption is strongly associated with hypertension (high blood pressure) in both men and women over the age of 40 years. Men who report consuming four drinks a day and women who reported consuming three drinks a day were more than twice as likely to have hypertension, than abstainers (Storey and Forshee 2002). Binge drinking can cause a surge in blood pressure that does not occur with steady alcohol consumption, suggesting that the manner of drinking is more critical than the amount (Marques-Vidal P et al. 2001). However other studies suggest that a drink a day can reduce arterial stiffness (Fleg 2002). Alcohol impairs the body's ability to tighten the blood vessels by disrupting the reflex that maintains blood pressure, when a person moves from a sitting to a standing position (Narkiewicz et al 2000).
People with hypertension appear to benefit from a reduction in alcohol consumption (Xin et al 2001). The Nurse’s Health Study, a long-term study of 100,000 women, showed a 15% hypertension risk reduction at 3 drinks a week, but a 30% increase in risk at 10-12 drinks per week, equivalent to 1½ a drinks daily (Thadhani 2002). Conversely, a small case controlled study of 60 postmenopausal women suggests heart protection from improved lipid levels at 1-2 drinks a day (Baer D 2002).
In the new study, a reduced risk of stroke was found in men and women aged 60 to 69 who consumed one to two drinks a day. The observed effect was limited to those who consumed wine and was not seen in younger people at all (Djousse 2002). A Medline review to ascertain the level at which cardiovascular mortality is lowest among drinkers aged 50-80 years suggests that between 7 to 13 units of alcohol per week for men and approx 3 units per week for women was optimal.
“The one relationship that is invariant across countries as well as different age groups of men and women is the zero-correlation between alcohol and ischemic heart disease mortality. This suggest that an increase in per capita consumption does not provide any cardio-protective effect at the population level.” (Norstrom Ed. 2001)
The brain is extraordinarily sensitive to alcohol. Alcohol is a depressant drug that reduces the pace of brain activity by a combination of effects. Alcohol affects the function of neurotransmitters by altering the communication between them (NIAAA 2001). A sufficient dose can shut down brain function that can lead to unconsciousness or death.
Alcohol dependence occurs through changes in the brain through long-term exposure. Prolonged exposure to alcohol can cause the brain to become dependent on the presence of alcohol in order to maintain an appropriate level of brain activity. Cessation of drinking following long-term use will result in a withdrawal syndrome. Prolonged abuse will result in the loss of brain cells. The direct toxic effect of alcohol on brain function is compounded by the accompanying poor nutritional status of long term abusers (NIAAA 2001).
Brain areas damaged by heavy alcohol use include:
Corpus callosum – Connects the right and left hemispheres
Frontal lobe – Contains regions of the cortex that control movement, language production, problem solving planning and social behaviour
Hippocampus – Controls memory of a factual nature
Mammillary body – A subregion of the hypothalamus related to memory formation
Parietal lobe – Contains regions of the cortex devoted to the senses, movement, spatial processing and memory and mathematics, grammar and spelling
Temporal lobe – Regions of the cortex devoted to auditory information, language comprehension, object identity and categorisation
Studies suggest that adolescent brain development involving memory, language skills, problem solving and attention is adversely affected by alcohol (Brown S 2000). Reduced function in the frontal lobes and temporal lobes can impair control and judgement and increase likelihood of aggression (Amen 2000).
While the liver is capable of regeneration and repair, long-term heavy alcohol use is the leading cause of death from liver disease. The three types of alcohol-related liver disease are fatty liver (reversible with abstinence), alcoholic hepatitis (inflammation) and cirrhosis (scarring). People with alcoholic liver damage are at greater risk of having hepatitis C (NIAAA 2001).
Heavy alcohol use can deplete the critical antioxidant glutathione leaving the lungs more vulnerable to infection and disease (Guidot 2002). However a recent study suggests that the antioxidant found in wine can improve lung function (Schunemann H 2002).
Alcoholic pancreatitis is a potentially fatal illness and most often occurs in men over 40 years. Long term alcohol consumption may lead to destruction of pancreatic tissue and blocked pancreatic ducts. While the risk of pancreatitis rises with increasing consumption it is unclear why only a small proportion of heavy drinkers develop the illness (Apte M 1997).
Alcohol may contribute to bone fracture beyond merely increasing the risk of falls and accidents. Dose dependent alcohol consumption (chronic or episodic) appears to lower bone density thus increasing bone fragility (ostopenia) (NIAAA 2001). This may be the result of a direct toxic effect or vitamin and mineral deficiencies and imbalance. The growing skeleton may be especially susceptible to the adverse effects of alcohol.
Alcohol’s effect on the hormonal system has widespread consequences for the entire body. The hormonal disturbances can result in cardiovascular abnormalities and reproductive deficits. Excessive consumption can cause bone disease and immune dysfunction increasing the risk of infections (Emanuelle N and Emanuelle M 1997).
A three way interaction exists between alcohol consumption, hormonal stress activity and the aging process. Age related changes at the cellular level may contribute to the body’s decreased ability to metabolise alcohol. At the same time alcohol abuse appears to exacerbate the aging process that may be the result of alcohol’s stimulatory effect on the hormonal hypothalamic-pituitary-adrenal (HPA) axis (Spencer and Hutchison 1999).
Sex and fertility
Alcohol abuse is associated with sexual dysfunction. Long term abuse in men is associated with impotence, sterility and testicular atrophy. In women the risk of menstrual disturbance, spontaneous abortion and premature menopause increase with the level of drinking (NIAAA 2001; Kesmodel et al 2002). Alcohol during pregnancy has direct toxic effect on fetal development that causes birth defects and neurobehavioural disabilities (Institute of Medicine 1996).
New studies are confirming what has been observed for centuries that excessive alcohol consumption results in immunodeficiency. This can increase the incidence and severity of diseases such as pneumonia, tuberculosis, liver disease, HIV, gastrointestinal infections and septicemia (NIAAA 2001).
Amen D. Regional cerebral blood flow in alcohol-induced violence: a case study. Journal of Psychoactive Drugs. 31 (4):389-393, 1999.
Andreasson S. Alcohol and J-Shaped Curves. Alcoholism: Clinical and Experimental Research 22 (7) 359-64, 1998.
Apte M , Wilson J and Korsten M. Alcohol-Related Pancreatic Damage: Mechanisms and Treatment. Alcohol Health and Research World. 21 (1): 13-20, 1997.
Baer J et al. Moderate alcohol consumption lowers risk factors for cardiovascular dises in postmenopausal women fed a controlled diet. American Journal Clinical Nutrition, 75:593-9, 2002.
Brown S. Adolescent Alcohol Dependence may damage brain function. Alcoholism: Clinical and Experimental Research, Vol 24, No 2, 2000.
Djoussé L, Ellison R, Beiser A, Scaramucci A, D’Agostino R and Wolf P. Alcohol Consumption and Risk of Ischemic Stroke: The Framingham Study. Stroke: 33:907-12, 2002.
Emanuelle N and Emanuelle M. The Endocrine System: Alcohol Alters Critical Hormonal Balance. Alcohol Health and Research World. 21 (1): 53 –64, 1997.
Fillmore K. Is Alcohol Really Good for the Heart? Addiction, 95(2): 173-174 (2000).
Fleg J. Presentation of finding from the Baltimore Longitudinal Study of Aging at the American Heart Association Conference (unpublished) 2001.
Green A and Pullen M. Moderate Drinkers Healthier than Abstainers and Ex Drinkers. American Journal of Preventive Medicine, News Release. November 2001.
Guidot D. Glutathione depletion in chronic alcohol abuse makes lungs vulnerable to life-threatening diseases. Presentation at the Experimental Biology 2002 Meeting New Orleans (Unpublished). Press Release 2002.
Gutjahr E, Gmel G and Rehm J. Relation between Average Alcohol Consumption and Disease: An Overview. European Addiction Research 7 (3) 117-127, 2001)
Hart C, Davey-Smith G, Hole D and Hawthorne V. Alcohol consumption and mortality from all causes, coronary heart disease, and stroke: results from a prospective cohort study of Scottish men with 21 years of follow up. British Medical Journal, 318:1725-1729, 1999.
Kesmodel U, Wisborg K Olsen S, Hendricksen T and Secher N. Moderate alcohol intake in pregnancy and the risk of spontaneous abortion. Alcohol and Alcoholism; 37: (1) 87-92 2002.
Lee N. University of Queensland School of Psychology study. Courier Mail page 3, Alcohol and other Drugs Council of Australia, 1999.
Marques-Vidal P et al. Different Alcohol Drinking and Blood Pressure Relationships in France and Northern Ireland: The PRIME Study. Hypertension 38:1361-6, 2001.
Mortenen E et al. Better Psychological Functioning and Higher Social Status May Largely Explain the Apparent Health Benefits of Wine. A Study of Wine and Beer Drinking in Young Danish Adults. Archive of Internal Medicine; 161: 1844-48.
National Institute on Alcohol Abuse and Alcoholism. 10th Special Report to the US Congress on Alcohol and Health: Highlights form Current Research. US Dept of Health and Human Sciences, 2000.
National Institute on Alcohol Abuse and Alcoholism. Alcohol Alert No 22, 1993. http://www.niaaa.nih.gov/ 2002.
National Institute on Alcohol Abuse and Alcoholism. Alcohol and Coronary Heart Disease. Alcohol Alert No 45 1999. http://www.niaaa.nih.gov/ 2002.
Narkiewicz, K., R.L. Cooley, and V.K. Somers. 2000. Alcohol potentiates orthostatic hypotension. Circulation 101(1):398.
Norstrom T, Ed. Alcohol in Postwar Europe: Consumption, drinking patterns, consequences and policy responses in 15 European countries. National Institute
of Public Health, European Commission 2001.
Shaper A and Wanamathee S. Alcohol intake and mortality in middle aged men with diagnosed coronary heart disease. Heart, 83:394-399, April 2000.
Smith Warner et al. Alcohol and Breast Cancer in Women: A pooled analysis of cohort studies. Journal of the American Medical Association; 279: 535-540 1998.
Shunemann H. (unpublished) White wine may benefit lungs. A study presented at the American Thoracic Society International Conference Atlanta 2002.
Spencer R and Hutchison K. Alcohol, Aging and the Stress Response. Alcohol Research & Health. 23 (4): 272-283, 1999.
Storey and Forshey. Hypertension Association with Obesity and Heavy Alcohol Consumption. (Unpublished). Presentation at the Experimental Biology 2002 Meeting in New Orleans press release 2002.
Thadhani R. Women’s blood pressure drops with 3 drinks a week. Archives of Internal Medicine, 162:569-574, 2002.
Thakker K. An overview of health risk and benefits of alcohol consumption. Alcoholism: Clinical and Experimental Research 2 (7) 1998.
Tsubono Y, Yamada S, Nishino Y et al. Choice of comparison group in assessing the health effects of moderate alcohol consumption. Journal of the American Medical Association 286 (10) 1177-1178. 2001.
Walsh C, Larson M, Evans C, Djousse L, Ellison C, Vasan R and Levy D. Alcohol Consumption and Risk for Congestive Heart Failure in the Framington Heart Study. Annals of Internal Medicine, 136 (3)181-191. 2002.
Wannamethee S and Shaper A. Type of alcoholic drink and risk of major coronary heart disease events and all-cause mortality. American Journal of Public Health, 89 (5): 685-90, 1999.
Xin X, He Jiang, Frontine G, Ogden L, Motsamai O and Whelton P. Effects of Alcohol Reduction on Blood Pressure. Hypertension, 38:1112, 2001.