WASHINGTON (NBC News) — People who drink diet sodas daily have three times the risk of stroke and dementia compared to people who drink one less than once a week, researchers reported Thursday.
It’s yet another piece of evidence that diet drinks are not a healthy alternative to sugary drinks, and suggests that people need to limit both, doctors said.
While the findings do not prove that diet drinks damage brains, they support other studies that show people who drink them frequently tend to have poorer health.
The researchers, led by Matthew Pase of the Boston University School of Medicine and colleagues, studied more than 4,000 people for their report, published in the journal Stroke.
“We found that those people who were consuming diet soda on a daily basis were three times as likely to develop both stroke and dementia within the next 10 years as compared to those who did not consume diet soda,” Pase told NBC News.
“Our study provides further evidence to link consumption of artificially sweetened beverages with the risk of stroke,” the team wrote. “To our knowledge, our study is the first to report an association between daily intake of artificially sweetened soft drink and an increased risk of both all-cause dementia and dementia because of Alzheimer’s disease.”
The team did not ask people which artificial sweetener they used. Some of those in the diet drinks were likely saccharin, acesulfame, aspartame, neotame, or sucralose, the researchers said.
To their surprise, the team did not find the same risk for sugar-sweetened beverages. But they found other troubling signs.
“In our first study we found that those who more frequently consume sugary beverages such as fruit juices and sodas had greater evidence of accelerated brain aging such as overall smaller brain volumes, they had poorer memory function and they also had smaller hippocampus, which is an area of the brain important for memory consolidation,” Pase said.
The researchers accounted for age, sex, education, overall how many calories people ate, diet quality, physical activity, and smoking. But they note that there may be others things that are also different about people who drink diet sodas.
Pase also noted that the risks are still low and people who love their daily fix of diet soda do not need to panic.
“Even if someone is three times as likely to develop stroke or dementia, it is by no means a certain fate,” Pase said. “In our study, three percent of the people had a new stroke and five percent developed dementia, so we’re still talking about a small number of people developing either stroke or dementia.”
The American Beverage Association, the lobbying group for the soda industry, said its products are safe. “The Alzheimer’s Association points out that the greatest risk factors for Alzheimer’s are increasing age, family history of Alzheimer’s, and genetics — not sugar intake, from any source,” it said in a statement.