Alcohol Risks and Benefits to Health

Introduction

Over the course of approximately 10,000 years, humans have been consuming fermented drinks while simultaneously debating their pros and cons. This ongoing discussion persists today, with the question of whether alcohol is beneficial or harmful still sparking lively discourse.

It is fair to assert that alcohol can be both a restorative and a toxin. The primary distinction lies in the quantity consumed. Moderate alcohol consumption appears to have positive effects on the cardiovascular system and may offer protection against type 2 diabetes and gallstones. On the other hand, excessive drinking is a significant cause of avoidable mortality in many countries. In the U.S., alcohol plays a role in around 50% of fatal traffic collisions. [1] Heavy alcohol use can lead to liver and heart damage, harm to unborn children, increased risk of developing breast and certain other cancers, as well as exacerbating depression, aggression, and relationship issues.

The dual nature of alcohol should not be unexpected. Ethanol, the primary active component in alcoholic beverages, is a simple molecule that impacts the body in a multitude of ways. It directly influences the stomach, brain, heart, gallbladder, and liver. Moreover, it affects blood lipid (cholesterol and triglyceride) levels, insulin, inflammation, and coagulation processes. Ethanol also alters mood, concentration, and coordination.

What Constitutes Moderate Alcohol Consumption and a Standard Drink?

Ambiguity surrounding the terms "moderate" and "a drink" has contributed to the ongoing debate about alcohol's effects on health.

In certain studies, "moderate drinking" is defined as consuming less than one drink per day, while in others, it refers to 3-4 drinks per day. The concept of "a drink" is also somewhat vague, and even among alcohol researchers, there is no universally accepted definition for a standard drink.

In the U.S., a drink is typically considered to be 12 ounces of beer, 5 ounces of wine, or 1½ ounces of spirits (hard liquor such as gin or whiskey). On average, each of these contains around 12 to 14 grams of alcohol, although there is now a broader range due to the production of microbrews and wines with higher alcohol content.

Is Red Wine Superior?

Some experts have proposed that red wine offers unique benefits, but other research indicates that the choice of beverage appears to have minimal impact on cardiovascular advantages. Determining the definition of moderate drinking requires striking a balance, as it lies at the point where alcohol's health benefits clearly surpass the risks.

Current consensus places this threshold at no more than 1-2 drinks per day for men and no more than 1 drink per day for women. This definition is adopted by the U.S. Department of Agriculture and the Dietary Guidelines for Americans 2020-2025, and is widely used in the United States.

There are risks and benefits, and it’s important to have the best information about all of those and come to some personal decisions, and engage one’s health care provider in that process as well.

Dr. Walter Willett, Harvard

The Adverse Effects of Alcohol

While many individuals consume alcohol in moderation, not everyone limits themselves to just one drink, and excessive consumption can have serious consequences.

Excessive alcohol consumption can significantly impact one's health. It can cause liver inflammation (alcoholic hepatitis) and lead to liver scarring (cirrhosis), which can be fatal. Additionally, it can elevate blood pressure and damage heart muscles (cardiomyopathy).

Heavy alcohol use has also been associated with several types of cancer: The World Cancer Research Fund and American Institute for Cancer Research have identified strong evidence linking alcohol to cancers of the mouth, pharynx, larynx, esophagus, breast, liver, colon, and rectum. The International Agency for Research on Cancer has concluded that both ethanol in alcohol and acetaldehyde, a byproduct of ethanol breakdown, are carcinogenic to humans when consumed in large quantities. The risk is further increased for drinkers who also smoke tobacco or maintain an unhealthy diet.

The issue of excessive alcohol consumption extends beyond the drinkers themselves, affecting their families, friends, and communities. According to the National Institute on Alcohol Abuse and Alcoholism and other sources:

• In 2014, approximately 61 million Americans were classified as binge alcohol users (consuming 5 or more drinks on the same occasion at least once a month) and 16 million as heavy alcohol users (consuming 5 or more drinks on the same occasion on 5 or more days in one month).
• Alcohol is involved in one out of three violent crime cases.
• In 2015, over 10,000 people lost their lives in automobile accidents involving alcohol.
• The annual cost of alcohol abuse is estimated at around $249 billion.

Even moderate drinking is not without risks. Alcohol can interfere with sleep and impair judgment. It can also interact dangerously with various medications, including acetaminophen, antidepressants, anticonvulsants, painkillers, and sedatives. Furthermore, alcohol can be addictive, particularly for those with a family history of alcoholism.

In 2015, over 10,000 people lost their lives in automobile accidents involving alcohol.

Alcohol Raises the Risk of Developing Breast Cancer

There is substantial evidence indicating that alcohol consumption elevates the risk of breast cancer, with the risk increasing in correlation with the amount of alcohol consumed.

A comprehensive prospective study that followed 88,084 women and 47,881 men for 30 years discovered that even one drink a day raised the risk of alcohol-related cancers (including colorectal, female breast, oral cavity, pharynx, larynx, liver, and esophagus) in women, primarily breast cancer, among both smokers and nonsmokers. For nonsmoking men, consuming 1-2 drinks a day was not associated with an increased risk of alcohol-related cancers.

In a combined analysis of six large prospective studies involving over 320,000 women, researchers found that consuming 2-5 drinks a day compared to no drinks increased the likelihood of developing breast cancer by up to 41%. The type of alcohol—wine, beer, or hard liquor—made no difference. This does not imply that about 40% of women who have 2-5 drinks a day will develop breast cancer. Rather, it represents the difference between approximately 13 out of every 100 women developing breast cancer during their lifetime—the current average risk in the U.S.—and 17 to 18 out of every 100 women developing the disease. This modest increase would result in a significant number of additional breast cancer cases annually.

Folate and Breast Cancer

A deficiency of folate in one's diet, or its supplement form folic acid, further increases the risk of breast cancer in women. Folate is necessary for new cell production and DNA change prevention. Folate deficiency, which can occur with heavy alcohol use, can cause gene alterations that may lead to cancer. Alcohol also elevates estrogen levels, which stimulate the growth of certain breast cancer cells. Consuming at least 400 micrograms of folate daily, alongside at least one alcoholic drink, appears to mitigate this heightened risk.

A strong association was found among three factors—genetics, folate intake, and alcohol—in a cohort from the Nurses' Health Study II involving 2,866 young women with an average age of 36 who were diagnosed with invasive breast cancer.

Women with a family history of breast cancer, who consumed 10 grams or more of alcoholic beverages daily (equivalent to one or more drinks), and had a daily intake of less than 400 micrograms of folate nearly doubled their risk (1.8 times) of developing the cancer. Women who consumed this amount of alcohol but did not have a family history of breast cancer and consumed at least 400 micrograms of folate daily did not experience an increased breast cancer risk.

Alcohol and Weight Gain

A single serving of alcohol typically contains 100-150 calories, so even a moderate consumption of three drinks per day can contribute over 300 calories. Mixed drinks that incorporate juice, tonic, or syrups further increase the calorie count, elevating the risk of weight gain over time.

Nonetheless, a prospective study that followed nearly 15,000 men in four-year intervals discovered only a slightly heightened risk of weight gain associated with higher alcohol intakes. Compared to participants who did not alter their alcohol consumption, those who increased their intake by two or more drinks per day gained slightly more than half a pound. It's worth noting that calorie intake (excluding calories from alcohol) tended to rise alongside alcohol consumption.

Alcohol Use Disorder or Alcoholism

Alcoholism, also known as alcohol use disorder (AUD), is a chronic and progressive disease characterized by an individual's inability to control their alcohol consumption, despite its negative impact on their health, relationships, and social life. Alcoholism not only affects the individual but also their loved ones and society as a whole.

Alcoholism can manifest in various ways, and its symptoms can range from mild to severe. Common signs include:

1. Increased tolerance to alcohol, requiring more to feel its effects.
2. Experiencing withdrawal symptoms, such as tremors, anxiety, or nausea, when not drinking.
3. Drinking in secret or lying about the amount consumed.
4. Neglecting personal, professional, or social responsibilities due to alcohol use.
5. Inability to control or reduce alcohol consumption, even when it leads to negative consequences.

Prolonged alcohol abuse can cause severe damage to the body, impacting both physical and mental health. Some of the potential health risks associated with alcoholism include:

1. Liver damage, such as cirrhosis or alcoholic hepatitis.
2. Increased risk of cardiovascular diseases, such as heart attack or stroke.
3. Weakening of the immune system, making the body more susceptible to infections.
4. Nutritional deficiencies and gastrointestinal problems.
5. Cognitive decline, memory loss, and increased risk of developing dementia.

Potential Health Benefits of Alcohol

What are some potential health benefits associated with moderate alcohol consumption?

Cardiovascular Disease

Over 100 prospective studies indicate an inverse relationship between light to moderate drinking and the risk of heart attack, ischemic (clot-caused) stroke, peripheral vascular disease, sudden cardiac death, and death from all cardiovascular causes. The effect is relatively consistent, with a 25-40% reduction in risk. However, increasing alcohol consumption to more than four drinks a day can raise the risk of hypertension, abnormal heart rhythms, stroke, heart attack, and death.

Alcohol and Heart Disease: Prospective Studies

The link between moderate drinking and a lower risk of cardiovascular disease has been observed in both men and women. This applies to individuals without heart disease, as well as those at high risk for heart attack, stroke, or death from cardiovascular disease, including people with type 2 diabetes, high blood pressure, and existing cardiovascular conditions. The benefits also extend to older individuals.

The idea that moderate drinking protects against cardiovascular disease is biologically and scientifically plausible. Moderate amounts of alcohol increase levels of high-density lipoprotein (HDL, or "good" cholesterol), and higher HDL levels are associated with greater protection against heart disease.

Moderate alcohol consumption has also been linked to beneficial changes, such as better insulin sensitivity and improvements in factors that influence blood clotting, including tissue type plasminogen activator, fibrinogen, clotting factor VII, and von Willebrand factor. These changes would likely prevent the formation of small blood clots that can obstruct arteries in the heart, neck, and brain, ultimately causing many heart attacks and the most common type of stroke.

Beyond the Heart

The benefits of moderate drinking aren't limited to the heart. In the Nurses' Health Study, the Health Professionals Follow-up Study, and other studies, gallstones and type 2 diabetes were less likely to occur in moderate drinkers than in non-drinkers. The emphasis here, as elsewhere, is on moderate drinking.

In a meta-analysis of 15 original prospective cohort studies that followed 369,862 participants for an average of 12 years, a 30% reduced risk of type 2 diabetes was found with moderate drinking (0.5-4 drinks a day), but no protective effect was found in those drinking either less or more than that amount.

The social and psychological benefits of alcohol can't be ignored. A drink before a meal can improve digestion or offer a soothing respite at the end of a stressful day; the occasional drink with friends can be a social tonic. These physical and social effects may also contribute to health and well-being.

Drinking Patterns Matter

It appears that the specific beverage consumed (beer or wine) isn't as vital as the manner in which it is consumed. Having seven drinks on a Saturday night and abstaining for the rest of the week doesn't equate to the same health implications as consuming one drink daily, even though the weekly total is identical.

In the Health Professionals Follow-up Study, drinking alcohol on at least three or four days per week was inversely correlated with myocardial infarction risk. The amount consumed, whether under 10 grams or over 30 grams daily, seemed less significant than the regularity of consumption. A similar trend was observed among Danish men.

An analysis of alcohol consumption in women from Nurses' Health Study I and II showed that lower amounts of alcohol (approximately one drink per day) spread across four or more days per week resulted in the lowest death rates from any cause, compared to women who consumed the same amount in one or two days.

The most conclusive method to study alcohol's effect on cardiovascular disease would involve a large trial in which participants are randomly assigned to consume one or more alcoholic beverages daily, while others receive drinks that look, taste, and smell like alcohol but are alcohol-free. Several trials have been conducted for weeks, months, and even up to two years to examine blood changes, but a long-term experimental trial on alcohol's effects on cardiovascular disease has not been performed.

A recent attempt in the U.S. to initiate an international study was funded by the National Institutes of Health. The proposal underwent peer review, and initial participants were randomized to either moderate drinking or abstinence. However, the NIH decided to halt the trial due to internal policy concerns after the fact. Regrettably, a future long-term trial on alcohol and clinical outcomes may never be attempted again. Nevertheless, the association between moderate drinking and cardiovascular disease likely represents a cause-and-effect relationship based on all available evidence to date.

Genetics and Alcohol Consumption

Research involving twins, families, and adoption demonstrates the crucial role of genetics in shaping an individual's alcohol preferences and susceptibility to alcoholism. Unlike the straightforward inheritance rules established by Gregor Mendel, alcoholism is influenced by multiple genes that interact with one another and environmental factors.

Furthermore, evidence suggests that genetic factors also impact how alcohol influences the cardiovascular system. An enzyme known as alcohol dehydrogenase is responsible for metabolizing alcohol. A particular variant of this enzyme, alcohol dehydrogenase type 1C (ADH1C), exists in two forms. One form rapidly breaks down alcohol, while the other does so more gradually. Moderate drinkers with two copies of the gene for the slower enzyme face a significantly lower risk of cardiovascular disease compared to those with two copies of the rapid enzyme gene. Individuals with one gene for each form lie somewhere in between.

The rapid enzyme variant may break down alcohol before it can positively affect HDL and clotting factors. Intriguingly, variations in the ADH1C gene don't impact heart disease risk in non-drinkers, providing compelling indirect evidence that alcohol itself contributes to heart disease risk reduction.

Evolving Advantages and Disadvantages

As we age, the pros and cons of moderate alcohol consumption shift. Generally, the risks are greater than the benefits until middle age, when the impact of cardiovascular disease becomes more significant in terms of morbidity and mortality.

• For expectant mothers, their unborn babies, individuals in recovery from alcoholism, people with liver disease, and those taking medications that interact with alcohol, moderate drinking presents minimal advantages and considerable hazards.
• For a 30-year-old man, the heightened risk of accidents related to alcohol use surpasses the potential cardiovascular benefits of moderate drinking.
• In the case of a 60-year-old man, consuming a daily alcoholic beverage may provide protection against heart disease, with the benefits likely outweighing any potential risks (assuming he is not susceptible to alcoholism).
• For a 60-year-old woman, assessing the balance between benefits and risks is more complex. Heart disease claims the lives of ten times more women annually (460,000) than breast cancer (41,000).

Nevertheless, research indicates that women tend to be more fearful of developing breast cancer compared to heart disease, which must be taken into account in the decision-making process.

The Crucial Balance: Weighing Pros and Cons

As alcohol affects each individual uniquely and people have diverse backgrounds and health histories, it is impossible to offer general recommendations about alcohol consumption. Each person must weigh the potential advantages and drawbacks of alcohol use, particularly when considering its potential medicinal properties.

Your healthcare professional can assist you in evaluating these factors, taking into account your overall health and the risk of alcohol-related conditions.

• For those who are slender, physically active, non-smokers, maintain a nutritious diet, and have no family history of heart disease, consuming alcohol may not significantly reduce the risk of cardiovascular disease.
• If you abstain from alcohol, there is no need to start drinking. You can achieve similar benefits through increased physical activity (either starting or enhancing your exercise routine) or adopting healthier eating habits.
• If you are a man with no history of alcoholism and at moderate to high risk of heart disease, a daily alcoholic beverage might help lower that risk. Moderate drinking can be particularly advantageous if you have low HDL cholesterol levels that do not improve with diet and exercise.
• For women with no history of alcoholism and at moderate to high risk of heart disease, the potential advantages of daily alcohol consumption must be weighed against the slightly increased risk of breast cancer.
• If you currently consume alcohol or plan to do so, maintain moderation—no more than 2 drinks per day for men or 1 drink per day for women. Additionally, ensure you consume sufficient folate, at least 400 micrograms daily.