A study in the journal Stroke showed a correlation between drinking diet soda and both stroke and dementia: people who drank at least one diet soda a day were three times as likely to have a stroke or develop dementia as those who avoided the beverages. Previous research had already uncovered a possible link with higher stroke risk. The findings in this study add some support to those results. The link with dementia, however, is new, and at minimum is enough cause for concern that it's worth studying further. Why might diet sodas contribute to these risks? Diet sodas are designed to trick the brain into thinking it's getting an extra dose of glucose (the brain's fuel), but eventually the trick is on us because the brain adapts to not receiving the added glucose by overcompensating in other ways (leading to a variety of effects still under investigation). Diet sodas could imbalance the bacterial jungle in our guts - the microbiome - causing unpredictable results. Since there's a bacterial superhighway from gut to brain, which we know interacts with key neurotransmitters, this theory may eventually tell us more of a much bigger brain story. This study didn't narrow down the exact types of artificial sweeteners that were consumed, so it's an open question how one may have affected the brain differently than another. In the meantime, curtailing how much of any artificial sweetener you ingest, along with added sugar, is a reasonable position to take.