Drinking lots of artificially sweetened beverages, such as diet sodas, comes with a 20% higher risk of an irregular heartbeat, a new study finds.
The research also revealed that consuming similar amounts of sugar-sweetened drinks was linked to a 10% bump in risk. Adults who reported drinking at least 2 liters, or roughly 67 ounces, of sweetened drinks a week saw these jumps in risk, compared to people who drank none.
However, the study found only an association between these beverages and irregular heartbeats — it can't say that sugar or artificial sweeteners actually cause the heart condition.
Related: Is Diet Coke bad for you?
In the study, published Tuesday (March 5) in the journal Circulation: Arrhythmia and Electrophysiology, researchers reviewed self-reported diet data from about 202,000 people in the U.K. Biobank, a repository of genetic and health data from half a million U.K.-based participants.
Over an average of nearly 10 years for each participant, the researchers checked to see who developed atrial fibrillation, or AFib for short.
This type of arrhythmia occurs when the upper chambers of the heart beat irregularly. AFib can cause blood clots and heart failure, and it's the leading cause of stroke, CNN reported.
People who consumed the equivalent of one 12-ounce artificially sweetened drink a day saw the greatest risk of AFib, compared to those who drank no sweetened beverages. These drinks were sweetened with ingredients such as sucralose, aspartame, saccharin and acesulfame.
However, adults who drank 1 liter (34 ounces) or less of pure juice with no added sugars, such as 100% orange or vegetable juice, had an 8% lower risk of the condition than those who drank artificially sweetened beverages, according to an American Heart Association (AHA) statement.
"This is the first study to report an association between no- and low-calorie sweeteners and also sugar-sweetened beverages and increased risk of atrial fibrillation," Penny Kris-Etherton, a member of the AHA's nutrition committee who was not involved in the study, said in the statement.
"While there is robust evidence about the adverse effects of sugar-sweetened beverages and cardiovascular disease risk, there is less evidence about adverse health consequences of artificial sweeteners," she said.
Some evidence has linked beverages made with sugar substitutes to an increased risk of heart attack and stroke.
In addition, in 2023, an arm of the World Health Organization (WHO) declared aspartame a "possible carcinogen," although the organization's process of identifying possible cancer-causing agents is fraught with problems. But the U.S. Food and Drug Administration (FDA) disagrees with the WHO's stance, stating that it hasn't found any link between aspartame and cancer.
Because the new study only observed people's beverage consumption habits, it could not demonstrate that artificial sweeteners or sugar actually cause AFib. For instance, it's possible that some underlying factors predispose people to both drink more diet soda and have the heart condition.
"Although the mechanisms linking sweetened beverages and atrial fibrillation risk are still unclear, there are several possible explanations, including insulin resistance and the body's response to different sweeteners," lead study author Dr. Ningjian Wang, a researcher at the Shanghai Ninth People's Hospital and Shanghai Jiao Tong University School of Medicine in China, said in the AHA statement.
"We still need more research on these beverages to confirm these findings and to fully understand all the health consequences on heart disease and other health conditions," Kris-Etherton added. "In the meantime, water is the best choice, and, based on this study, no- and low-calorie sweetened beverages should be limited or avoided."
This article is for informational purposes only and is not meant to offer medical advice.
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