A diet drink a day can up the odds of a stroke and dementia
People who have 'diet' drinks every day are almost three times more likely to suffer a stroke or dementia, research suggests.
However, researchers found no such trend with sugary drinks, though they warned people not to view sugary drinks as a "healthy option".
The new research, published in the American Heart Association's journal 'Stroke', is based on data for more than 4,300 people taking part in the Framingham Heart Study.
Those in the stroke arm of the study were over the age of 45, while those in the dementia arm were over 60.
All participants filled in questionnaires on their food and drink intake at three separate points during the 1990s.
Researchers then followed the group for 10 years, noting 97 cases of stroke during that period, and 81 cases of dementia - of which 63 were specifically Alzheimer's disease.
The researchers said future studies should look at the effect of diet drinks on factors known to increase the risk of stroke and dementia, such as high blood pressure.
But Dr Elizabeth Coulthard, consultant senior lecturer in dementia neurology at the University of Bristol in the UK, said: "Although interesting, this paper does not tell us that artificially sweetened drinks cause stroke or dementia."
She said "it is more likely that there is a group of people who both use artificially sweetened drinks and are at higher risk of dementia, presumably because they have a risk factor, such as diabetes, for which a low sugar diet has been recommended".
Due to the fact the study is observational and based on food questionnaires, the researchers said further studies are needed on the links.