New research suggests a potential link between gender, alcohol consumption, and the risk of developing atrial fibrillation—a serious condition that can lead to stroke or heart failure.

Analyses conducted by Australian and Swedish researchers examined previous studies and revealed that while consuming one standard drink daily poses a similar risk for both men and women, drinking between one and four standard drinks a day increases the risk of atrial fibrillation for men alone.

In contrast, women face a significantly higher risk to their heart health when their alcohol intake reaches six standard drinks per day, compared to their male counterparts.

The study was co-authored by Mohammad Hossein Hadi, a research fellow at the University of Melbourne.

“The sex-specific pattern we observed might be influenced by various factors, including biological differences such as alcohol metabolism, hormonal influences, and body composition,” Hadi explained to SBS News.

Australian health guidelines recommend no more than 10 standard drinks a week for men and women, while other experts have told SBS News there is “no safe amount” of alcohol consumption.

There is a daily recommended limit of no more than four standard drinks a day.

What is atrial fibrillation?

Alcohol consumption can lead to a range of health issues, including atrial fibrillation, a common heart rhythm disorder.

Hadi described it as a “major heart condition” that presents similar symptoms in men and women.

“Some people are asymptomatic, while others have persistent symptoms that affect daily functioning,” he said.

“Some people notice palpitations, shortness of breath, fatigue, dizziness, or reduced exercise tolerance, while others have no symptoms and are diagnosed incidentally.”

He said that atrial fibrillation can increase a person’s morbidity and mortality, often requiring ongoing management.

“It is associated with a substantial health burden.”

While the relative risk of atrial fibrillation differed between men and women based on intake, risk increased across the board among people who drink more frequently.

Differences in men and women

Rachel Visontay, a postdoctoral research fellow at the University of Sydney, explained that different groups of people break down alcohol at varying rates.

Men are more efficient at metabolising alcohol for a few reasons, according to Visontay.

“One, they’ve got a higher amount of water, which is what disperses alcohol,” she said.

“And they’ve also got higher concentrations of the enzymes in the stomach that do the first part of breaking down the alcohol, which means you’ve got less of it going into the liver and less of it going into the bloodstream.”

Typically, this means men are less likely to experience the short and long-term health impacts of drinking when compared to women consuming a comparable amount.

Visontay explained that Australia has a set guideline — recommending no more than 10 standard drinks a week for men and women — whereas in some countries, the threshold for men is higher, reflecting a greater ability to tolerate alcohol.

Generic variations in different ethnicities can also affect a person’s capacity to break down alcohol.

One group that is often less able to break down acetaldehyde — one of the first byproducts the body makes when processing alcohol — is people of East Asian background, who can be more likely to experience what is colloquially termed ‘Asian flush’.

“They’ll start to get quite red quite quickly, and they might get some uncomfortable side effects like heart palpitations and nausea,” she said.

“That will not just cause problems in the short term, like making drinking unpleasant, but in the long term as well.”

Long-term harms of alcohol are “numerous” and include an increased risk of cancers, dementia and cognitive impairment.

“There’s really strong evidence for the relationship between alcohol and increased risk for cancers, and in particular the parts of the body where alcohol is making contact,” she said.

No safe amount of alcohol

Claire Gardner, manager of food and nutrition at the Australian Heart Foundation, told SBS News that following the Australian guidelines helps lower the risk of alcohol-related harm, but it does not remove all risk.

“There is no completely safe level of alcohol consumption,” she said.

“High-quality studies, including those looking at just one standard drink, have found that even low levels of alcohol can raise the risk of heart disease.

Even small amounts of alcohol increase the risk of developing neck, throat, colorectal or liver cancer.

Gardner and Visontay also explained that past studies saying alcohol like red wine can be good for heart health are now outdated, and have been disproved by newer research.

“The supposed benefits of light drinking were likely influenced by the fact that light drinkers often have healthier lifestyles overall, not because alcohol itself is protective,” Gardner said.

“Alcohol is not a defining feature of heart‑healthy eating patterns, even in the Mediterranean diet, where benefits come from the overall diet, not the wine.”

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