We are a species that loves our fermented grapes. We've been making and drinking wine since 6000 B.C. Even as far back as 2,000 years ago there were wine bars on every street in Roman cities. In 2014, Americans consumed an estimated 893 million gallons of wine. That's a lot of quaffing.
But is a glass of wine a good thing? Studies are released all the time promoting the health benefits of wine in moderate consumption. A daily glass of wine might boost antioxidants, increase "good" cholesterol and lower the risk of heart disease. However, other research highlights health risks including an increased chance of some cancers and some heart concerns.
So with that in mind, here's a look at all the different things science says about what can happen at wine o’clock — the good, the bad and the ugly all in their fermented glory.
To start things off, just what is moderate consumption? A standard drink is equal to 14.0 grams (0.6 ounces) of pure alcohol, which generally equates to 5 ounces of wine (and is roughly equivalent to 1.5 ounces of liquor or 12 ounces of beer, though variations in strength will throw that off). According to the Dietary Guidelines for Americans, moderate alcohol consumption means having up to one drink per day for women and up to two drinks per day for men. Most studies quantify amounts used in research.
The benefits of drinking a glass of wine a day
1. Boosts antioxidants
Much of the research interest in wine has to do with antioxidants. Known as polyphenols, and especially flavonoids and resveratrol, these antioxidants are believed to work to protect the cells and tissues against harm that can lead to various diseases like cancer and heart disease. Wine, especially red wine, is loaded with them.
2. May limit atherosclerosis
According to the American Heart Association (AHA), a number of studies suggest that the polyphenolic compounds in red wine may play an active role in limiting the start and progression of atherosclerosis, a disease in which plaque builds up inside the arteries.
3. Increases 'good' cholesterol
Having one to two drinks per day has been shown to boost HDL cholesterol by about 12%, reports the AHA. This “good” cholesterol can help clean up the bad low-density lipoprotein (LDL) cholesterol from the system and lessen the amount of material available to clog up the arteries.
4. Decreases risk of heart disease
When the data from 51 epidemiological studies were analyzed together for this AHA report, they revealed that the risk of coronary heart disease decreased by approximately 20% when up to two alcoholic drinks were consumed per day.
5. Lessens risk of heart attack
Meanwhile, in the comprehensive longitudinal study known as the Health Professionals Follow-Up Study, 38,077 male health professionals who were free of heart disease were observed over the course of 12 years. Among the crew, drinking one to two drinks per day, three to four days per week decreased the risk of having a heart attack by as much as 32%.
6. May reduce risk of stroke
The AHA also notes that light to moderate drinking was found to be associated with around a 20% reduction in the risk for ischemic stroke and possibly helps to prevent subsequent strokes.
7. Good for your gut
A study published in Gastroenterology found that people who drink red wine have a greater diversity of bacteria living in their guts than people who drink beer, white wine, cider or spirits. A diverse gut microbiome is a sign of good gut health. Researchers believe the good microbe mix is due to the many polyphenols in red wine.
8. Lowers stress and anxiety
A study published in the journal Neuropharmacology found that a compound in red wine called resveratrol might offer protection from symptoms of depression and anxiety. The compound appears to block the expression of an enzyme that is linked to the control of stress in the brain, researchers say.
9. Lessens likelihood of gallstones
In the famed Nurses’ Health Study as well as the Health Professionals Follow-up Study (and other studies) gallstones were less likely to occur in moderate drinkers than in non-drinkers.
10. Decreases diabetes risk
A meta-analysis of observational studies, published in Diabetes Care, found a 30% reduced risk of Type 2 diabetes in moderate alcohol consumers. Another large study found the risk of drinking even less than one drink a day five times a week offered a 36% lower risk of diabetes.
Possible health risks of drinking wine
1. Might not play nicely with medications
Alcohol interacts in possibly dangerous ways with a number of medications, including acetaminophen, antidepressants, anticonvulsants, painkillers and sedatives.
2. Messes with your folate
Alcohol blocks the absorption of folate, the important B vitamin that, among other things, helps build DNA, and is essential for accurate cell division. Alcohol also inactivates folate in the blood and tissues. It’s possible that this interaction may be how alcohol consumption increases the risk of cancer, see below.
3. Increases risk of fast heartbeat
Frequently drinking small amounts of alcohol could increase your risk of atrial fibrillation or an abnormally fast heartbeat. Researchers in Korea looked at data from more than 9.7 million patients to see how many of them developed the heart condition. They found that those who drank every day had the highest risk, compared to those who drank alcohol once or twice a week. There was no connection between the condition and binge drinking.
4. May boost breast cancer risk
When someone begins to exceed the amount defined as moderate, all kinds of things can start to go wrong. Numerous studies have shown that too much alcohol can contribute to cardiovascular disorders, high blood pressure, and certain electrical disturbances of the heartbeat. Excessive alcohol use can lead to liver cirrhosis, a plethora of cancer types, pancreatitis, neurological disorders, motor vehicle accidents and addiction.
But even moderate alcohol seems to increase the risk of breast cancer. More than 100 epidemiologic studies have shown that the risk of breast cancer rises with increasing alcohol intake. A meta-analysis of 53 of those 100 studies showed that women who drank more than around three drinks a day had 1.5 times the risk of developing breast cancer as nondrinkers. In general, researchers found that for every 10 grams of alcohol consumed per day (slightly less than one drink), there was a corresponding 7% increase in the risk of breast cancer.
5. But may reduce the risk of other cancers
Just to keep things totally confusing, however, numerous studies have shown that alcohol consumption is associated with a decreased risk of renal cell (kidney) cancer and non-Hodgkin lymphoma. In a meta-analysis of non-Hodgkin lymphoma studies including 18,759 participants, there was a 15% lower risk of the disease among alcohol drinkers compared with nondrinkers.
6. To drink or not to drink?
The Centers for Disease Control and Prevention (CDC) says that it's not recommended that anyone start drinking or drink more frequently just because of potential health benefits since moderate alcohol intake also is associated with “increased risk of breast cancer, violence, drowning, and injuries from falls and motor vehicle crashes.”
Moderation is key
The Harvard School of Public Health points out that alcohol is both a tonic and a poison. "The difference lies mostly in the dose. Moderate drinking seems to be good for the heart and circulatory system, and probably protects against Type 2 diabetes and gallstones. Heavy drinking is a major cause of preventable death in most countries. In the U.S., alcohol is implicated in about half of fatal traffic accidents." And clearly, drinking too much is a problem; while those with a personal or family history of alcohol abuse or liver disease should avoid drinking alcohol altogether.
We all have unique personal and family histories, so the bottom line is that a glass of wine offers each of us a different array of benefits and risks. Whether or not to have a drink at the end of the day requires careful balancing of these benefits and risks, a job that may be best accomplished by knowing the science and having a chat with your health care provider.
To your health!
Editor's note: This story has been updated with new information since it was published in December 2015.