Threats Of Drinking
When Science Says Enough Is Enough
Samoon Ahmad :
For many Americans, summer is the most relaxing time of the year. Particularly when the weather is nice, millions of people around the country choose to spend the day or evening outside, enjoying the company of friends and family while lighting up the grill and having a few drinks. It has become an American tradition.
Casual drinking on occasion poses very few immediate threats, provided one is not pregnant, on certain medications that interact with alcohol, or planning to get behind the wheel or engage in any other kind of potentially reckless behavior while the acute effects of alcohol intoxication are felt.
Once the effects have worn off, there is little long-term damage that can come from the occasional glass of wine, beer, or spirit. If done frequently and in large amounts, however, alcohol can become a major health risk. Constant and heavy drinking is associated with a host of ailments, including liver disease, heart disease, diseases of the digestive tract, and cognitive decline. Furthermore, alcohol abuse and alcoholism can also wreak havoc on one's familial, social, and work lives.
This should not be groundbreaking news to anyone. However, there is a vast middle ground between having one drink every now and then and alcoholism, and the truth about the potential risks to one's health when it comes to moderate drinking are blurry. On the one hand, moderate drinking is not a universal concept. It changes from country to country. On the other, recent studies have contradicted the age-old wisdom about the benefits of what constitutes moderate drinking in the minds of the public. Even moderate drinking can impact one's life expectancy and cognitive function, and the risk of stroke, heart failure, hypertensive disease, and fatal aortic aneurysm jumps significantly even for those whose drinking may seem to be less than problematic by some standards.
What Is a Standard Drink?
What defines a "standard drink" varies by country. In the United States, a standard alcoholic drink contains 14 grams of pure alcohol. In the United Kingdom, a standard alcoholic drink is significantly smaller-8 grams. In much of Europe, the standard is somewhere in the middle (typically 10 g or 12 g).
In the US, 14 grams of pure alcohol is equivalent to the following:
Â· 1.5 fluid ounces of spirits like vodka, rum, or whiskey (typically around 40% alcohol)
Â· 5 fl oz of wine (typically around 12% alcohol)
Â· 12 fl oz of beer (typically around 5% alcohol)
It should be noted that these are rough guidelines and that there can be significant variations between types of alcohol, particularly when it comes to beer. While most mass-produced beer is close to 5% alcohol, craft beers can range from 3.5% to 18%. Luckily, most craft brewers now indicate the alcohol by volume (ABV) contained in their beer on either the can or the bottle to avoid confusion.
Variations in ABV may have a far larger impact than one assumes at first. For example, if two people each order a beer at a pub-one individual having an imperial pint of Irish stout, one individual having a pint of India pale ale-neither will have a standard drink. An imperial pint of the most famous Irish stout is 20 oz of 4.2% ABV beer, which means this one "drink" contains 19.591 g of pure alcohol. A pint of an IPA that is 6.0% ABV, meanwhile, contains 22.399 g of pure alcohol. By US standards, the one Irish stout is about 1.4 standard drinks, while the pint of IPA is closer to 1.6 standard drinks. To the two individuals enjoying their beers, however, they will probably think that they are only having one drink.
What is Moderate Drinking?
Like a "standard drink," "moderate drinking" can have several definitions. In common parlance, a moderate drinker is someone who does not drink to the point of drunkenness unless on special occasions. It is a nebulous concept that people often use to distinguish between a heavy drinker-someone who may frequently drink to the point of drunkenness-and the occasional drinker or non-drinker. These are not scientific terms by any means; they are merely the phrases that have come to be adopted by individuals in their day-to-day use of language, and their definitions are highly subjective.
Conversely, there are official standards for "moderate drinking" that are based on analyses of safe or low-risk levels of alcohol consumption. Like "standard drink," they vary from country to country. For example, in the UK, "moderate drinking" is defined as consuming 14 standard drinks per week or less. This is the equivalent of six pints of 4% beer or seven 5 oz glasses of 12% wine. In the US, the guidelines for moderate drinking as established by the Department of Health and Human Services and the Department of Agriculture are an average of two drinks per day for men and one drink per day for women or less. When one consumes more than this amount, it is referred to as "excessive drinking" by the guidelines, which note, "Excessive drinking increases the risk of many chronic diseases and violence and, over time, can impair short-term and long-term cognitive function."
Studies have shown that women often feel the acute effects of alcohol sooner than men, as women tend to weigh less than men, have less water in their bodies than men, and produce less alcohol dehydrogenases (a class of enzymes that allow us to metabolize alcohol) than men. Hormones may also impact the rate at which alcohol is metabolized. Due to these differences, what constitutes moderate drinking for a woman is often thought to be less than what constitutes moderate drinking for a man. These distinctions are codified in the US guidelines, the Canadian guidelines, and the Irish guidelines. As noted above, these distinctions are absent from the UK guidelines.
"In comparison to those who reported drinking >0-=100 g (mean usual 56 g) alcohol per week," the authors of the study continued, "Those who reported drinking >100-=200 g (mean usual 123 g) per week, >200-=350 g (mean usual 208 g) per week or >350 g (mean usual 367 g) per week had shorter life expectancy at age 40 years of approximately 6 months, 1-2 years, or 4-5 years respectively." They also found that, "Men who reported consuming above the UK upper limit of 112 g per week had a shorter life expectancy at age 40 years of 1.6 yearsâ€¦and men who reported drinking above the US upper limit of 196 g per week had a shorter life expectancy at age 40 years of 2.7 yearsâ€¦compared with men who reported drinking below these respective upper limits."
In other words, the study's findings indicate that moderate drinking for men and women should be no more than 100 g, approximately the same amount recommended for women by the US guidelines.
The groundbreaking study did not only examine life expectancy. More narrowly, it found that those who drink more than 100 g per week increase their risk of stroke, coronary disease excluding myocardial infarction, heart failure, and fatal aortic aneurysm, even after adjusting for age, sex, smoking, and history of diabetes. Conversely, the researchers found that drinking more than 100 g per week correlated with more non-fatal myocardial infarctions than fatal, though they noted that this benefit does not outweigh the other risks associated with drinking more than 100 g per week.
The study did not have access to enough information to determine if alcohol was linked with additional adverse outcomes, including non-fatal liver disease, injuries, or psychiatric comorbidities, though another study did recently find a systematic bias in previous studies claiming that moderate drinking can protect cognitive function as the body ages. A paper published in Frontiers in Aging Neuroscience by Linda B. Hassing of the University of Gothenburg in Sweden claims that such studies were flawed because their control groups included numerous non-drinkers who had only become abstinent because of health issues-including alcohol abuse earlier in life.
Hassing also found other key disparities between the control and the drinker groups. The controls had, on average, a lower education level, a lower socioeconomic status, a higher body mass index, and higher rates of diabetes and hypertension. There were fewer smokers, however. Still, the main finding of the paper was that, when the abstainer bias was controlled, it was found that, "There was a negative and not a positive effect of light alcohol intake on cognitive performance."
Hassing also called into question the current "safe limit" for men and women, as defined by the US guidelines. "Given the results from the present study, these guidelines may potentially be too high."
As these studies have shown, even moderate drinking is associated with numerous risks that outweigh the benefits of drinking more than 100 g per week. However, this was not an indictment of alcohol or a plea for all people to abstain from drinking altogether. It was meant to clarify the numerous definitions of "moderate drinking" to allow individuals to improve their ability to make their own life decisions and to better understand the risks associated with alcohol consumption.
To calculate the number of grams in a drink, the following equation was used: Volume x (alcohol by volume x volumetric mass density) = pure alcohol mass.
Â· For the stout: .591 l x (0.042 x 789.24 g/L) = 19.591 g.
Â· For the IPA: .473 l x (0.06 x 789.24 g/L) = 22.399 g.
(Samoon Ahmad, M.D. is a Professor of Psychiatry, NYU School of Medicine; Unit Chief, Inpatient Psychiatry, Bellevue Hospital Center; and Founder of Integrative Center for Wellness in New York City).