Among that "high intake" group, they found multiple signs of accelerated brain aging, including smaller overall brain volume, poorer episodic memory, and a shrunken hippocampus, all risk factors for early-stage Alzheimer's disease.
The US study found those who drank a can of artificially-sweetened pop - such as Diet Coke or Pepsi Max - daily were at three times the risk of suffering the most common form of stroke compared to non-drinkers.
While sugared drinks have already been linked with increased risk of serious diseases, the study has prompted renewed debate over whether artificially sweetened drinks also pose a serious risk to health. A new study finds it may risk you to stroke and dementia even though many believe the can is healthier compared to sweetened drinks.
"These studies are not the be-all and end-all, but it's strong data and a very strong suggestion", said Sudha Seshadri, Professor at Boston University School of Medicine (MED) in the US.
Matthew Pase from Boston University School of Medicine said it is highly recommended to drink water instead of sweetened beverages.
In addition to being an observational study which can not prove cause and effect, the authors note the study several other limitations, including that the overwhelming majority of participants were white.
"In fact, based on the evidence, Public Health England is actively encouraging food and drink companies to use low-calorie sweeteners as an alternative to sugar and help people manage their weight". Some of those in the diet drinks were likely saccharin, acesulfame, aspartame, neotame, or sucralose, the researchers said.
"In our study, 3% of the people had a new stroke and 5% developed dementia, so we're still talking about a small number of people developing either stroke or dementia".More news: North Korea fails in new missile test: Seoul
"To our knowledge, our study is the first to report an association between daily intake of artificially sweetened soft drink and increased risk of both all-cause dementia and dementia because of Alzheimer's disease", the co-authors added.
Heather Snyder, senior director of medical and scientific operations at the Alzheimer's Association, called the new study "a piece of a larger puzzle" when it comes to better understanding how your diet and behaviors impact your brain.
"We know that sugary and artificially sweetened beverages are not great for us".
Yet another study showed that artificial sweeteners alter bacteria in the gut, which might also have a negative effect, Pase said.
"We have a robust body of literature on the adverse effects of sugary drinks".
"They may have a role for people with diabetes and in weight loss, but we encourage people to drink water, low-fat milk, or other beverages without added sweeteners".
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 can not - prove cause and effect.