Numerous studies have suggested that consuming a daily glass of wine or beer can decrease the risk of heart disease and mortality. However, a recent review of evidence suggests that these studies are flawed and that the potential health benefits of moderate alcohol consumption disappear when considering these flaws and biases.

According to the researchers, moderate alcohol intake, at most, has no discernible positive or negative effect on an individual’s health. On the other hand, consuming three or more drinks daily substantially elevates the risk of premature death.

One drink per week up to two drinks per day is considered moderate drinking. It is the amount of alcohol that several papers imply lowers your chance of dying early

However, once the researchers accounted for the study’s flaws and biases, co-author Tim Stockwell noted that the perceived benefits of moderate drinking substantially diminish, and in some instances, disappear entirely.

According to the US National Institutes of Health, a typical American beverage contains around 14 grams of pure alcohol. That’s about the same as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of hard liquor.

Stockwell and coworkers reviewed 107 papers that looked at the correlation between alcohol use and mortality. Nearly 5 million people from many different countries took part in these studies.

And this is what the authors found:

Ex-drinkers don’t stay sober

For instance, Stockwell noted that several studies often mix past drinkers together with lifelong abstainers, calling them all “non-drinkers.”

Yet according to Stockwell, most former drinkers have stopped or reduced alcohol intake due to health issues. According to the latest research, former drinkers actually have a 22% greater mortality risk than those who abstain from alcohol.

Their inclusion in the “non-drinker” group skews the findings, giving the impression that occasional light drinking is beneficial, according to Stockwell.

In the new study, the researchers combined the data and made adjustments to account for issues such as the “former-drinker bias.”

“We’ve put Band-Aids on all of these bad studies,” comments Stockwell, “to try and explore how these different characteristics result in the appearance of health benefits.”

The pooled adjusted study data revealed that neither low-volume drinkers (up to 24 grams per day, or almost two drinks) nor infrequent drinkers (less than 1.3 grams of alcohol, or one drink per two weeks), had a substantially lower chance of dying.

The researchers discovered that people who used 25 grams to 44 grams of alcohol daily, or about three drinks, had a marginally but not significantly higher chance of dying.

The findings also revealed a considerably elevated risk of mortality for those who consumed 45 grams or more of alcohol per day.

Those who use 65 grams or more of alcohol each day, or more than four drinks, are at the greatest risk. Compared to infrequent drinkers, their risk of mortality was around 35% greater.

Catherine Lesko, an assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore, commented, “There’s this question about whether low-level drinking is beneficial, and I think I’d take this to mean that it’s really not particularly beneficial. I don’t know that it’s harmful, very low-level drinking. But a lot of the results are reinforcing the harmful effects of even moderate to high level drinking.”

The analysis also revealed that alcohol has a more pronounced impact on women’s risk of death at lower amounts.

The increased risk of death associated with alcohol consumption consistently appeared higher for women compared to men. For instance, women who consume 65 grams or more daily face a 61% higher risk of death, which is almost twice the risk faced by men who drink the same amount.

Pat Aussem, Associate Vice President of Consumer Clinical Content Development for the Partnership to End Addiction, explained, “Women experience alcohol differently than men because of biological factors. Even when drinking the same amount of alcohol, women will have higher blood alcohol levels, feel intoxicated more quickly and take longer to metabolize it.”

Given that alcohol usage has been connected to at least 22 distinct causes of mortality, Stockwell said these findings make sense.

According to Stockwell, drinking alcohol raises the risk of heart disease, stroke, several malignancies, and liver illness. It also makes people more likely to die from car accidents, falls, homicides, and suicides.

Stockwell stated that other research, which considers genetic factors, “confirm our conclusion” that moderate drinkers don’t have protection against heart disease or early death.

“So our results are consistent with other studies using stronger design.”

According to Aussem, research has identified a “continuum of risk” based on weekly alcohol consumption. The associated risk of harm is as follows:

• Consuming 2 or fewer standard drinks per week is likely to prevent alcohol-related consequences for yourself or others.
• Consuming between 3 to 6 standard drinks per week increases the risk of developing various types of cancer, such as breast and colon cancer.
• Consuming 7 or more standard drinks per week significantly increases the risk of heart disease or stroke.

According to Aussem, the risk of alcohol-related consequences significantly rises with each standard drink consumed. This risk increases in direct proportion to the amount of alcohol consumed, as repairing the damage to cell tissue in the body and brain becomes more challenging. Therefore, it is advisable to consume less alcohol as even small steps towards reducing alcohol intake can be beneficial in lowering the risk of alcohol-related diseases such as cancer and cardiovascular disease.

The researchers acknowledged some shortcomings in their study. They noted that the measurement of alcohol consumption in most studies was not entirely accurate and that self-reported alcohol consumption was likely underreported in many instances.

To obtain a more precise assessment of the risks associated with alcohol, future studies should focus on specific drinking-related diseases and connect them with specific demographic groups, as suggested by Stockwell. For instance, studies could analyze the differences in cancer risk from alcohol consumption between men and women.

Moreover, the researchers recommended that future studies use occasional drinkers as the reference group because they tend to possess more typical health characteristics than abstainers.

The findings of the study were published in JAMA Network Open.

Image Credit: Getty