Alcohol consumption and health

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The relationship between alcohol consumption and health has been the subject of formal scientific research since at least 1926, when Dr. Raymond Pearl published his book, Alcohol and Longevity asserting that drinking alcohol in moderation is associated with greater longevity than either abstaining or drinking heavily.Template:Ref Subsequently, various studies have examined the health effects of different degrees of alcoholic beverage consumption; while it is widely recognized that heavy or abusive drinking has health hazards, including cell and organ damage in the brain, liver, and kidneys, and the immune system, "moderate consumption," frequently defined as the consumption of 1-3 alcoholic drinks daily (depending on the age and gender of the subjects) has been hypothesized to have a positive effect on longevity.

A large number of independent peer-reviewed studies in modern medical literature support the hypothesis that moderate alcohol consumption can be associated with benefits in longevity and reductions in coronary heart disease, stroke, and other diseases. Proposed mechanisms of these benefits include the effect of alcohol on cholesterol levels, insulin activity, blood pressure, and the chemistry of blood clotting. Frequently, such studies qualify these findings with admonitions against heavy alcohol consumption or abuse, due to the negative health effects known to be associated with this behavior.

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Background

Research extending back as far as 1926 has demonstrated that drinking in moderation is associated with greater longevity than is either abstaining or abusing alcohol.Template:Ref

One possible explanation is the effect of alcohol on cardiovascular disease, the leading cause of mortality in the United States and many other industrialized countries.

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Physiological effects of ethanol

Medical research demonstrates that alcohol increases HDL (“good cholesterol”), decreases thrombosis (blood clotting), reduces fibrinogen (a blood clotter), increases fibrinolysis (clot dissolving), reduces artery spasm from stress, increases coronary blood flow and increases insulin sensitivity -- all good for heart health.

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Known negative effects of alcohol

The U.S. Department of Health & Human Services’ National Toxicology Program listed alcohol as a known carcinogen in 2000.

Drinking alcohol, especially along with smoking, increases the risk of cancers of the mouth, esophagus, pharynx, larynx and liver in men, and of breast cancer in women, according to the National Cancer Institute. Fortunately, except for breast cancer, these cancers are all rare. Moderate consumption doesn’t increase the risk of the most common cancers, except for breast cancer. Also fortunately, an exhaustive review of the research evidence has found that women who drink alcohol and have a high folate intake have no more risk of breast cancer than those who abstain from alcohol.

However, it is inevitable that humans intake some moderate amount of alcohol, even if they never drink in their lives. This is because many of the bacteria in our intestines use alcohol fermentation as a form of respiration. This metabolic method produces alcohol as a waste product, in the same way that our metabolism results in the formation of carbon dioxide and water. Thus, we always intake some quantity of alcohol, which is produced by these benign bacteria. In fact, if we eat enough carbohydrates (a few pieces of bread, for instance), the alcohol levels in our bowels can soar to the equivalent of a few ounces of wine, some quantity of which will inevitably be absorbed by the intestinal wall, and thus circulated throughout our bloodstream. In nature, the quantity of alcohol necessary to prevent heart disease is mostly produced by these microorganisms.

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Modern debate

The significant debate today regarding moderate drinking and health is about whether or not physicians should recommend moderate drinking to alcohol abstainers, unless contraindicated. Some fear that introducing abstainers to alcohol could make them alcoholic and abuse alcohol to the detriment of their health and the safety of others.

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Modern studies

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Alcohol consumption and longevity

Doll et al. (2005) published the results of a 23-year prospective study of 12,000 male British physicians aged 48-78, finding that overall mortality was significantly lower in the group consuming an average of 2-3 "units" (standard alcoholic drinks) per day than in the non-alcohol-drinking group (relative risk 0.81, confidence interval 0.76-0.87, P = 0.001).Template:Ref The authors noted that the causes of death that are already known to be augmentable by alcohol accounted for only 5% of the deaths (1% liver disease, 2% cancer of the mouth, pharynx, larynx, or oesophagus, and 2% external causes of death) and were significantly elevated only among men consuming >2 units/day.

In a 1996 American Heart Association scientific statement, Thomas A. Pearson, MD, Ph.D noted, "A large number of observational studies have consistently demonstrated a J-shaped relation between alcohol consumption and total mortality. This relation appears to hold in men and women who are middle aged or older. The lowest mortality occurs in those who consume one or two drinks per day.10 In teetotalers or occasional drinkers, the rates are higher than in those consuming one or two drinks per day. In persons who consume three or more drinks per day, total mortality climbs rapidly with increasing numbers of drinks per day."Template:Ref

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Alcohol consumption and heart disease

Template:Main In the above-noted AHA statment, Pearson reviewed the evidence supporting the effect of alcohol consumption on coronary heart disease (CHD): "More than a dozen prospective studies have demonstrated a consistent, strong, dose-response relation between increasing alcohol consumption and decreasing incidence of CHD. The data are similar in men and women in a number of different geographic and ethnic groups. Consumption of one or two drinks per day is associated with a reduction in risk of approximately 30% to 50%. Studies of coronary narrowings defined by cardiac catheterization or autopsy show a reduction in atherosclerosis in persons who consume moderate amounts of alcohol. In general, the inverse association is independent of potential confounders, such as diet and cigarette smoking. Concerns that the association could be an artifact due to cessation of alcohol consumption in persons who already have CHD have largely been disproved."Template:Ref

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Alcohol consumption and stroke

Berger et al.,(1999) in a study of over 22,000 male physicians aged 40-84 years old over an average of 12 years, found that "light-to-moderate alcohol consumption" reduces the overall risk of stroke and the risk of ischemic stroke in men, with a benefit apparent with as little as one drink per week, and no greater effect seen at greater consumption of up to one drink per day.Template:Ref

A 2003 meta-analysis by Reynolds et al. of 35 previous studies of the effect of alcohol consumption on stroke risk found that "compared with abstainers, consumption of more than 60 g of alcohol per day was associated with an increased relative risk of total stroke, 1.64 (95% confidence interval [CI], 1.39-1.93); ischemic stroke, 1.69 (95% CI, 1.34-2.15); and hemorrhagic stroke, 2.18 (95% CI, 1.48-3.20), while consumption of less than 12 g/d was associated with a reduced relative risk of total stroke, 0.83 (95%, CI, 0.75-0.91) and ischemic stroke, 0.80 (95% CI, 0.67-0.96), and consumption of 12 to 24 g/d was associated with a reduced relative risk of ischemic stroke, 0.72 (95%, CI, 0.57-0.91). The meta-regression analysis revealed a significant nonlinear relationship between alcohol consumption and total and ischemic stroke and a linear relationship between alcohol consumption and hemorrhagic stroke."Template:Ref (emphasis added)

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Health effect and type of alcohol consumed

In "Review of moderate alcohol consumption and reduced risk of coronary heart disease: is the effect due to beer, wine, or spirits?" (BMJ 1996;312:731-736 (23 March)) Eric B. Rimm et al. concluded that "results from observational studies where alcohol consumption can be linked directly to an individual's risk of coronary heart disease, provide strong evidence that all alcoholic drinks are linked with lower risk. Thus, a substantial portion of the benefit is from alcohol rather than other components of each type of drink."Template:Ref

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Other studies

The Director of the National Institute on Alcohol Abuse and Alcoholism has written that "numerous well-designed studies have concluded that moderate drinking is associated with improved cardiovascular health," [1] and the Nutrition Committee of the American Heart Association reports that "the lowest mortality occurs in those who consume one or two drinks per day." [2]

The World Health Organization Technical Committee on Cardiovascular Disease asserted that the relationship between moderate alcohol consumption and reduced death from heart disease could no longer be doubted. (Wilkie, S. Global overview of drinking recommendations and guidelines. AIM Digest, Supplement, June 1997, 2-4, p. 4)

The U.S. National Institute on Alcohol Abuse and Alcoholism (NIAAA) has completed an extensive review of current scientific knowledge about the health effects of moderate alcohol consumption. It found that the lowest death rate from all causes occurs at the level of one to two drinks per day. That is, moderate drinkers have the greatest longevity.[3]

The medical studies establishing this relationship are large (some include over 200,000 people), cross-cultural (have been conducted in countries around the world), and are sometimes long-term (the longest beginning in 1948 and continuing to this day).[4]

To test the hypothesis that the results may reflect the poor health of alcoholics who now abstain, some studies have restricted the abstainers studied to lifelong teetotalers. Others have controlled for lifestyle factors, income levels, educational levels and other factors. The results have remained the same: Moderate drinkers tend to live longer than abstainers or heavy drinkers.

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Alternatives and further debate

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Recommending alcohol consumption to "teetotalers"

Eight years ago, an editorial in the Journal of the Royal Society of Medicine opined that the recommendation to be a moderate drinker is "not only meaningless but also irresponsible" given that the many obvious health hazards of alcohol abuse outweigh "the benefits of alcohol [which] are small and ill-understood" particularly when so many other cardiovascular treatments are available.

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Comparison with health benefits of exercise and diet

Some suggest that the benefits of moderate drinking could be obtained from a regimen of eating a very low-fat diet, vigorously exercising regularly, eliminating salt from the diet, and losing weight. On the other hand, Dr. Eric Rimm of Harvard reports that people have increases of 10 to 30 percent in HDL in a week from drinking alcohol. That’s much easier for most people than following a demanding diet and exercise program.

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See also

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Notes

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References

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