Scientists at Boston University School of Medicine followed around 4,500 people for ten years and discovered that people who drank sugary drinks were more likely to have a poor memory and a smaller brain, although there wasn’t a link with stroke or dementia. So just a shrinking brain (or brain atrophy as the scientists call it) as measured by MRI scans.
They also found that having one diet drink or more a day appeared to raise the risk of stroke threefold and there was also a link with dementia.
It doesn’t prove causation so whether people who thought they might be at risk of dementia chose artificially sweetened drinks deliberately is one possibility.
And not everyone is convinced by the results. One researcher at Glasgow University suggested that it might be reverse causality in the case of the artificially sweetened drinks. i.e. being ill forces you to give up things like alcohol or sugary drinks.
He did concede however that sugary drinks were bad for you on several levels being a source of refined sugar and harmful to your teeth.
So while there are risks with artificially sweetened drinks the answer is not to switch to full sugar varieties but to drink water.
Don’t forget that diet drinks can actually help you put on weight