ReviewAlcohol and Cardiovascular Health: The Dose Makes the Poison…or the Remedy
Section snippets
Americans’ Drinking Habits
Among all American adults, about two-thirds report that they at least on occasion consume alcohol, and 44% are regular drinkers, defined as someone who has at least 1 drink per week.6 These regular drinkers consume an average of 4.2 alcoholic drinks per week. While a similar proportion of men and women consume alcohol, men on average ingest 6.2 alcoholic beverages per week compared with 2.2 drinks per week for women. Whites are more likely to consume alcohol than nonwhites, and on average,
What Constitutes a Drink?
By definition, a standard drink, regardless of the variety, contains 14 g of ethanol (0.6 fl oz of pure alcohol).7, 8 This equates to 12 oz of beer (about 5% ethanol), 5 oz of table wine (about 12% ethanol), or 1.5 oz of hard liquor or distilled spirits (about 40% ethanol).7, 8 Alcohol consumption can also be quantitated in units, whereby 1 U equals 10 mL or 8 g of ethanol, which corresponds to the amount of alcohol an average adult can metabolize in 1 hour. Thus, for example, 25 mL of whiskey,
Primary Prevention
The health effects of drinking are determined by the quantity and pattern of ethanol consumption.5 Observational studies consistently report that light to moderate drinkers are at lower risk for CV diseases than abstainers, and heavy drinkers are at the highest risk. A meta-analysis involving 1 million individuals reported that light to moderate alcohol consumption was associated with highly significant decreases in death during follow-up, with maximum protection noted at one-half to 1 drink
Secondary Prevention
Light to moderate alcohol intake has also been shown to improve outcomes in patients with established CV disease. In a recent meta-analysis of 8 prospective studies involving 16,351 patients with a history of CV disease, the familiar J-shaped curve was observed with maximal protection by alcohol at approximately 26 g/d (or about 2 drinks daily).16 Studies evaluating alcohol’s effects on patients who have had a myocardial infarction (MI) also report the typical J-shaped relationship between
Alcohol and Arrhythmias
Decades ago, the moniker “holiday heart” was suggested for acute cardiac arrhythmias, typically atrial fibrillation (AF), observed commonly in individuals drinking heavily during times of celebration.24 Unquestionably, heavy alcohol use, whether short-term or long-term, can precipitate arrhythmias.25 In the Copenhagen City Heart Study, consumption of more than 35 drinks per week correlated with higher risk of AF in men.26 Above a “safe” threshold of about 1 drink per day, the relative risk of
Alcohol and HF
Ethanol at higher doses is a cardiotoxin. Habitual heavy alcohol consumption can result in a specific cardiac disease known as alcoholic cardiomyopathy, which accounts for about one-third of all cases of nonischemic dilated cardiomyopathy in the United States.33 Individuals who consume more than 90 g of alcohol per day, which corresponds to about 7 drinks per day, for at least 5 years are at risk for the development of alcoholic cardiomyopathy and HF. Without complete abstinence, the 4-year
Alcohol and Hypertension
Habitual alcohol consumption raises blood pressure (BP) in a dose-dependent fashion. Long-term heavy drinking is one of the most common reversible causes of hypertension (HTN); excessive alcohol intake is responsible for approximately 16% of cases of HTN worldwide.39 The American Society of Hypertension warns that consuming more than 2 alcoholic drinks per day increases the risk for high BP.40 Beyond the first 1 or 2 drinks per day, each additional alcoholic drink will increase BP by
Alcohol and Stroke
Heavy drinking and chronic alcoholism are strong independent risk factors for stroke.47, 48, 49 Even so, most studies reveal a J-shaped association between alcohol and ischemic stroke, with a protective effect from light to moderate drinking and an elevated risk of stroke with heavy drinking50, 51, 52 (Figure 7). A recent study of 47,000 Japanese women followed for an average of 17 years found that ethanol consumption of 300 g/wk or more (21 or more drinks per week) increased total stroke by
Alcohol and DM
Consistent data indicate that regular light to moderate drinking is associated with substantial reductions in type 2 DM of 30% to 40%, irrespective of the alcoholic beverage consumed.55, 56, 57 In the Physicians’ Health Study, light to moderate alcohol consumption was associated with a decreased risk of type 2 DM during 12 years of follow-up.58 However, the protection that moderate drinking provides against new-onset diabetes is attenuated or abolished with higher doses (more than 4 drinks per
Cardioprotective Mechanisms of Action
The main active ingredient of any alcoholic beverage is ethanol, and most evidence indicates that this compound, rather than any other specific component of a drink, is the primary factor for both conferring health benefits and causing toxicity, depending on the pattern of consumption and dosing.66, 67 Accumulating scientific evidence suggests that light to moderate alcohol intake may enhance insulin sensitivity, elevate high-density lipoprotein (HDL) cholesterol, reduce inflammation, increase
Inconsistency of Cardioprotection Among Various Ethnicities
The cardioprotective effect of light to moderate drinking has not been consistently replicated among all the ethnicities and nations that have been studied.44, 84, 85 The INTERHEART study,86 a landmark 27,000-patient international epidemiological study, found that regular alcohol intake was associated with a decrease in the risk of MI in both sexes and all adult age groups. Individuals from 50 different nations were included in the INTERHEART study, which found that regular alcohol intake
Ideal Drinking Patterns, Doses, and Beverages
The standard definition of light to moderate alcohol intake is up to 1 drink per day for women and up to 2 drinks per day for men. Among the various alcoholic beverages, red wine, likely owing to its unique array of nonalcoholic components, is generally associated with the best health outcomes, especially for CV issues.17, 82, 83, 89, 90 Binge drinking, usually defined as episodic excessive alcohol intake (≥5 drinks within a few hours) often with intent to become intoxicated, is associated with
Warnings and Precautions
The Atherosclerosis Risk in Communities (ARIC) study found that among individuals deemed to be at low risk for addiction, moderate alcohol consumption was safe and did not lead to adverse outcomes related to problem drinking.96 However, other studies indicate that among nondrinkers, it is not possible to reliably predict who might be at increased risk for falling into a pattern of dangerously high alcohol intake once they begin drinking.3, 5 Indeed, habitual alcohol intake appears to be a
Acknowledgments
We thank Darwish Naji, MD (Saint Luke’s Mid America Heart Institute and University of Missouri-Kansas City) for assistance with data discovery and analysis.
References (99)
- et al.
Global burden of disease and injury and economic cost attributable to alcohol use and alcohol-use disorders
Lancet
(2009) - et al.
Alcohol and cardiovascular health: the razor-sharp double-edged sword
J Am Coll Cardiol
(2007) - et al.
Alcohol consumption and cardiovascular mortality among U.S. adults, 1987 to 2002
J Am Coll Cardiol
(2010) - et al.
Alcohol consumption is directly associated with carotid intima-media thickness in Finnish young adults: the Cardiovascular Risk in Young Finns Study
Atherosclerosis
(2009) - et al.
Alcohol consumption and mortality in patients with cardiovascular disease: a meta-analysis
J Am Coll Cardiol
(2010) - et al.
Comparison of outcomes among moderate alcohol drinkers before acute myocardial infarction to effect of continued versus discontinuing alcohol intake after the infarct
Am J Cardiol
(2010) - et al.
Alcohol consumption, atherosclerotic progression, and prognosis among patients with coronary artery bypass grafts
Am Heart J
(2006) - et al.
Arrhythmias and the “Holiday Heart”: alcohol-associated cardiac rhythm disorders
Am Heart J
(1978) - et al.
Atrial fibrillation in the 21st century: a current understanding of risk factors and primary prevention strategies
Mayo Clin Proc
(2013) - et al.
Alcohol consumption and risk of atrial fibrillation: a meta-analysis
J Am Coll Cardiol
(2011)