Drinking Diet Soda Linked to Stroke, Dementia Risk, Study Says

You may want to ease up on that diet soda you're so fond of – given new research showing the habit potentially increases your chances of getting a stroke or dementia.

A link between the two is a takeaway from a new study published in Stroke, a journal of the American Heart Association.

Those who drank diet soda every day had a nearly three-times-as-likely chance of stroke or dementia development, study author Matthew Pase said in a statement. That said, the study didn't reveal a direct cause-and-effect relationship.

For the study, researchers tapped data from the Framingham Heart Study to examine 2,888 people all more than 45 years old, and 1,484 people more than 60 years old, all from Framingham, Massachusetts. They took into account the number of both sugar-laden drinks and artificially-sweetened soft drinks people drank during the 10 year period of 1991 to 2001, and studied them several times between those years, reports CNN. Researchers documented stroke (for those over 45) and dementia (for those over 60) occurrence over the following 10 years.

Drinking these artificially-sweetened soft drinks each day led to an approximately three times higher risk of having a stroke or developing dementia, respectively.

The same couldn't be said for sugary drinks like fruit juice and sodas sweetened with sugar. Research on such consumption published in Alzheimer's & Dementia found people who more frequently consume sugary beverages over time were more likely to have poorer memories and smaller brain volumes.

"I was surprised that sugary beverage intake was not associated with either the risks of stroke or dementia because sugary beverages are known to be unhealthy," Pase, of the Boston University School of Medicine, told CNN.

"Our observation that artificially sweetened, but not sugar-sweetened, soft drink consumption was associated with an increased risk of stroke and dementia is intriguing," according to the study. "Like sugar-sweetened soft drinks, artificially sweetened soft drinks are associated with risk factors for stroke and dementia, although the mechanisms are incompletely understood, and inconsistent findings have been reported," it adds.

An American Beverage Association statement defended low-calorie sweeteners in response to the study.

"While we respect the mission of these organizations to help prevent conditions like stroke and dementia, the authors of this study acknowledge that their conclusions do not – and cannot – prove cause and effect," according to the statement. "And according to the National Institutes of Health (NIH), many risk factors can increase an individual's likelihood of developing stroke and dementia including age, hypertension, diabetes and genetics. NIH does not mention zero calorie sweeteners as a risk factor."

One doctor discussed a theory of his regarding the study, though acknowledging it's unproven.

"When the authors controlled for hypertension and diabetes and obesity the effects diminish, which implies that some of the effects of artificially sweetened beverages could still be going through a vascular pathway," Dr. Ralph Sacco of the University of Miami Miller School of Medicine, who wrote an editorial that was published with the study, told CNN.