Alcohol use and overuse is another issue that is often associated with the college years. People consume alcoholic drinks for many reasons—to socialize, celebrate, relax, escape, and as part of cultural and religious practices. According to surveys, 56% of the U.S. adult population reports having consumed alcohol in the past 30 days. Among college students aged 18 to 22 years, the percentage is slightly higher: about 60% of college students have reported drinking alcohol. However, the prevalence of both binge drinking and heavy drinking in college students is far higher than the general adult population. According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), “abusive and underage college drinking are significant public health problems, and they exact an enormous toll on the intellectual and social lives of students on campuses across the United States.”

Alcohol is the common name for ethanol, a potentially intoxicating ingredient found in beer, wine, and liquor. Alcohol is not a nutrient, but does provide energy in the form of calories (7 kcal per gram). It has potent druglike effects, acting as a central nervous system depressant. Microscopic yeast obtain energy from simple sugars in grains or fruit via a metabolic pathway called fermentation, which produces alcohol and carbon dioxide. The carbon dioxide may be released into the air, or the carbon dioxide may be trapped in the beverage causing it to be carbonated, as when beer is brewed. Beer is made by the fermentation of grains; wine is made from grapes or other fruit. Gin, rum, vodka, and whiskey are distilled, which involves heating a fermented mixture and then cooling it to condense the alcohol content into a more concentrated liquid form.

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A standard alcoholic drink is comprised of 14 grams (0.6 fluid ounces) of pure alcohol (ethanol), which can typically be found in 12 ounces of beer, 5 ounces of wine, or 1.5 ounces (a “shot”) of 80-proof distilled spirits or liquor. The alcohol content of liquor is half the proof, so 80 proof means 40% alcohol. While defining a “standard” drink is useful for establishing and following health guidelines, in practice, the alcohol content in a typical serving varies significantly. Many cocktails may contain the alcohol equivalent of three or more standard drinks. (INFOGRAPHIC 19.5)

Question 19.4

Alcohol is readily absorbed into the bloodstream through diffusion and then is transported to the body’s cells and tissues and dispersed throughout the water-containing portions of the body. About one-fifth of all alcohol consumed is absorbed through the stomach; the rest is absorbed in the small intestine. When consumed in moderate amounts, alcohol is metabolized primarily in the liver by a two-step process to form acetate. In the first step, the enzyme alcohol dehydrogenase converts alcohol to acetaldehyde, which is a highly reactive and toxic compound that can damage cellular components, including DNA. Acetaldehyde is then converted to acetate by the enzyme acetaldehyde dehydrogenase, and acetate then disperses to tissues throughout the body where it is converted to acetyl-coenzyme A, which can be used as a source of energy in the liver and elsewhere in the body. With higher levels of alcohol intake, the excessive amount of acetyl-coenzyme A that is produced in the liver results in high levels of fat synthesis that can cause a fatty liver, and eventually cause liver damage. Most alcohol is metabolized to acetate in the liver, but a small amount can also be metabolized in the stomach by the same two-step process, while even smaller amounts are excreted through our breath, sweat, and urine. (INFOGRAPHIC 19.6)

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Question 19.5

Alcohol stays in the blood and body fluids until the liver is able to detoxify all the alcohol that has been consumed. In general, the liver can only metabolize about an ounce of alcohol per hour, regardless of how much has been consumed. Thus it is important to limit intake to prevent excessive alcohol accumulation in the blood. But many factors above and beyond the amount and rate of alcohol consumption can influence how intoxicated a person gets while drinking. These factors include the person’s sex, body weight, food intake before or during alcohol consumption, his or her use of drugs or prescription medications, and even genes.

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Women, for instance, experience a more rapid rise in their blood alcohol levels than do men of the same size with similar alcohol intakes. This heightened effect is primarily a result of differences in body composition. Alcohol disperses in body water, and women—who have proportionally more body fat than men—have lower levels of total body water, causing alcohol to be more concentrated in the smaller volume of water. It is also often stated that the metabolism of alcohol in the stomach—before it ever reaches the blood—is faster in men than in women. However, more recent studies generally find no evidence for this. The presence of food in the stomach can serve to slow alcohol’s absorption by the stomach and its passage into the small intestine, thereby reducing the rate at which the alcohol appears in the bloodstream.

The concentration of alcohol in breath and urine mirrors the concentration of alcohol in the blood, so the blood alcohol concentration (BAC) of an individual can be determined by measuring the amount of alcohol in the breath. The BAC is the standard means of assessing the extent of a person’s alcohol impairment; a BAC of 0.08% is the legal limit for intoxication in the United States for drivers 21 years and older. A woman weighing 130 pounds easily exceeds the legal limit after consuming the equivalent of two alcoholic drinks. (INFOGRAPHIC 19.7)

Question 19.6

Alcohol consumption can provide potential health benefits. However, it is important to recognize that the evidence for the beneficial effects of alcohol is not as strong as the evidence for its harmful effects. Also, the risk-to-benefit ratio of light to moderate drinking is more favorable in those older than 50 years than it is for those who are younger than 50.

In healthy adults, moderate alcohol consumption—defined by the Dietary Guidelines for Americans as having up to one drink per day for women and up to two for men—is associated with a reduced risk of several chronic diseases and conditions, including heart disease, stroke, diabetes mellitus, abdominal obesity, and dementia, as well as a reduction in overall mortality risk. The most significant health benefits of light to moderate drinking seem to be on the cardiovascular system, with the risk of heart disease typically being reduced by 30% to 35%, with increases in high-density lipoprotein cholesterol contributing significantly to this reduction in risk. It is important to note, however, that excessive alcohol consumption causes hypertension and impairs cardiac function. And binge drinking, even in those who typically drink only lightly, increases the incidence of heart attacks and death. Even just an occasional binge-drinking episode virtually eliminates the protective effects seen with otherwise light to moderate intakes.

And although not depicted in the U.S. MyPlate, many national food guides from around the world include moderate alcohol consumption as a component of a healthful diet in adults. (Note that the definition of moderate consumption refers to the amount consumed on any single day and not the average over several days.) The most beneficial drinking pattern associated with a decrease in the risk of cardiovascular disease seems to be the consumption of one to two glasses of red wine immediately before or during the evening meal, as is practiced in many Mediterranean countries. However, it is not known if the benefits result from the alcohol itself, or from the social bonding or the avoidance of excess consumption that is promoted by this tradition. It is important to consider that the demonstrated benefits may also relate to the lifestyle habits and practices of people who consume moderate amounts of alcohol.

The Dietary Guidelines for Americans emphasize, however, that people should not begin drinking or drink more frequently because of these potential health benefits, because it is not possible to predict in which individuals alcohol abuse will become a problem. Also, alcohol consumption can have harmful effects on our health as well. Alcohol consumption is associated with an increased risk of some types of cancer, and excessive intake is associated with violent crime, drowning, and injuries from falls and motor vehicle crashes. Recent studies actually conclude that there is no safe level of alcohol consumption with regard to one’s risk of cancer. Even light drinking is associated with increased risk of cancers of the mouth, throat, esophagus, and breast. And the more alcohol one drinks, the greater the risk. Also, there are many confounding variables and unanswered questions as to the effect of moderate alcohol intake on overall health, chief among them the lifestyle characteristics of moderate drinkers that can contribute to reduced risk. In other words, people who drink moderately may have other healthy lifestyle habits that contribute to the reduction in disease and mortality risk. (INFOGRAPHIC 19.8)

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Question 19.7

Alcohol can have other adverse long-term effects on health. Alcohol affects every single cell in the body, so chronic use and abuse can have widespread detrimental effects on organs and body systems including the brain, cardiovascular system, liver, digestive system, and immune system. Excessive alcohol use is the third leading cause of death for people in the United States each year, and it is the single strongest risk factor for death among males 15 to 59 years of age. Intoxication, too, can lead to impaired brain function because alcohol disrupts the production and function of neurotransmitters. This leads to impaired judgment, reduced reaction time, and loss of balance and motor skills, all of which increase the risk of motor vehicle crashes, violence, and other injuries. Alcohol also increases blood flow to skin and accelerates the loss of heat from the body, greatly increasing the risk of hypothermia if intoxication results in a loss of consciousness while in a cold environment. Finally, alcohol use can lead to alcohol dependence, coma, and death, if the alcohol is consumed too rapidly and in large amounts. (INFOGRAPHIC 19.9)

Question 19.8

Certain people should never consume any alcohol. These include children and adolescents—yet underage drinking, though illegal, is nevertheless a huge public health issue. People aged 12 to 20 years drink 11% of all alcohol consumed in the United States, and more than 90% of this alcohol is consumed in excessive amounts in relatively short periods. Alcohol consumed during years of critical brain development can cause permanent impairment of cognitive function and increase the risk of fatal and nonfatal injuries. Plus, children who consume alcohol before the age of 15 are five times more likely to become alcohol dependant than are adults who begin drinking at age 21. Kids who drink alcohol are also more likely to engage in risky sexual behaviors, have poorer school performance, and are at higher risk for suicide as well as more likely to commit homicide than other kids.

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Pregnant women, and women planning to become pregnant, should also abstain from drinking alcohol, as there is no known safe level of alcohol use during pregnancy. Several conditions, including fetal alcohol spectrum disorders (FASDs), have been linked to alcohol use during pregnancy. FASDs represent a group of conditions that can occur in a person whose mother drank alcohol during pregnancy. The effects range in severity and can include physical as well as behavioral and learning problems. Even moderate drinking (one to six alcoholic drinks per week) in pregnant women has been shown to decrease the IQ of their child when tested at eight years of age.

Individuals who plan to drive, operate machinery, or take part in other activities that require attention, skill, or coordination, as well as individuals who have medical conditions or take certain medications, should not consume alcohol. It is also wise for people with a personal or family history of alcohol use disorder, alcohol abuse, or who are unable to limit their alcohol intake to moderate levels, to abstain from alcohol use.

Among college students in particular, binge drinking, a pattern of alcohol consumption that brings the BAC to 0.08% or higher, is a big problem. This pattern of drinking usually corresponds to consuming five or more drinks on a single occasion for men or four or more drinks on a single occasion for women, generally within about two hours. As many as 17% of the U.S. population reports binge drinking, but as many as 40% of college-aged students have engaged in binge drinking in the past month. Even college students who don’t drink can still be affected by the drinking of others. (INFOGRAPHIC 19.10)

Question 19.9

Alcohol abuse, also common among college students, is a pattern of drinking that has negative consequences for one’s health, relationships, and academic and work performance. Signs of alcohol abuse include a failure to fulfill responsibilities, drinking despite dangers or consequences, aggressive or violent behavior while intoxicated, legal issues related to alcohol, and increasing dependency on alcohol. Frequent heavy drinking can increase alcohol tolerance by ramping up the activity of an alternate pathway of alcohol metabolism in the liver (not involving alcohol dehydrogenase). As a result, the rate at which alcohol is metabolized is increased, thereby requiring a person to drink more and more alcohol to produce the same effects. In addition, this alternative pathway produces highly reactive chemical compounds (reactive oxygen species) that cause widespread damage to tissues throughout the body. Ongoing alcohol abuse can lead to alcohol use disorder, too. Alcohol use disorder is a medical diagnosis given to individuals who have severe problems with alcohol and meet certain diagnostic criteria.

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People can determine if they or their friends or loved ones have a problem with alcohol by checking for common signs and symptoms. (INFOGRAPHIC 19.11)

Question 19.10

A common consequence of alcohol consumption is the development of a hangover as the BAC falls following an episode of excessive drinking. Although individuals exhibit large differences in hangover susceptibility, the characteristic symptoms include headache, tiredness, impaired cognitive function, thirst, dizziness, nausea, and altered mood. The underlying causes of hangover are not well-understood. However, research suggests that alterations in immune system function resulting in the production of a variety of hormone-like molecules (cytokines) and an increase in inflammation are the greatest contributors to a hangover’s development. Blood glucose concentrations are also often observed to decrease during a hangover, which may contribute to symptoms of weakness, fatigue, and altered mood. There is also some evidence that elevated concentrations of acetaldehyde in blood may cause tissue damage that contributes to the symptoms of hangover. Current research neither supports the notion that symptoms result from dehydration, nor that rehydration can reduce the severity of symptoms. Furthermore, the consumption of beer and wine does not have a dehydrating effect as the fluid volume of these beverages more than offsets the increased rate of water loss caused by alcohol consumption. Other factors may contribute to hangover severity, including the type of alcohol consumed (darker beverages tend to produce more severe symptoms) and disrupted sleep patterns.

There are also nutritional considerations associated with alcohol use. As alcohol contains seven calories per gram, it is a fairly dense source of energy. Yet because it lacks overall nutrient value, alcohol is considered a source of “empty calories.” (INFOGRAPHIC 19.12) The Dietary Guidelines for Americans recommend that less than 5% of total calorie intake should come from alcohol. Chronic alcohol abuse can compromise nutrition by reducing the secretion of digestive enzymes, impairing nutrient absorption and utilization, contributing to potential nutrient deficiencies. In addition, alcohol often displaces more nutrient-dense foods, resulting in dietary inadequacies.

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College drinking can have multiple potential adverse and dangerous consequences, both short term and long term. Even if students are unwilling to consider abstaining, they should strive to drink responsibly by moderating intake, not drinking and driving, and not contributing to excessive intake by others. Awareness is the first step: Individuals should track their alcohol consumption patterns, as doing so can not only help them recognize a problem, but it can also help them set goals and come up with strategies for cutting down. Virtually all college campuses have resources and services that can support students in more responsible alcohol use. One national program that can help is the NIAAA’s Rethinking Drinking program.