10-year study: Having one or more diet sodas a day nearly triples the risk of having a stroke or Alzheimer's; overall risk is still low

A study suggests a connection between diet soda and both stroke and dementia, "with people drinking diet soda daily being almost three times as likely to develop stroke and dementia as those who consumed it weekly or less," Fred Barbash reports for The Washington Post.

The lead researcher, Matthew Pase of Boston University, said the findings “included a higher risk of ischemic stroke, where blood vessels in the brain become obstructed, and Alzheimer’s disease dementia, the most common form of dementia.”

Pase stressed that the study, published in the journal Stroke, showed only correlation, not causation, and a low overall risk of stroke and dementia, but said diet drinks “might not be a healthy alternative” to sugary ones. And he cautioned that diet-soda drinkers shouldn't go back to sugared drinks.

"They have been associated not only with obesity and its consequences, such as diabetes, but with poorer memory and smaller overall brain volumes," Barbash notes. "A parallel study of sugary drinks did not find an association with stroke or dementia."

The 10-year study looked at 2,888 people 45 and over for the development of a stroke, and 1,484 older than 59. It “found that those who reported consuming at least one artificially sweetened drink a day, compared to less than one a week, were 2.96 times as likely to have an ischemic stroke, caused by blood vessel blockage, and 2.89 times as likely to be diagnosed with dementia due to Alzheimer’s disease,” the American Heart Association said.

“So, the bottom line is, ‘Have more water and have less diet soda,” Christopher Gardner, director of Nutrition Studies at the Stanford Prevention Research Center, said in the AHA news release.

Barbash writes, "The artificial sweeteners consumed by those in the study included saccharin, acesulfame-K, and aspartame. Other sweeteners, including sucralose, neotame and stevia have been approved by the FDA since, the study said."

The American Beverage Association replied:  “Low-calorie sweeteners have been proven safe by worldwide government safety authorities as well as hundreds of scientific studies and there is nothing in this research that counters this well-established fact. . . . 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.”