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There have been a lot of hue and cry about the risk of artificial sweeteners causing every thing from bladder cancer to brain hemorrhages, bipolar disorders etc.
However there is no scientific proof for most of these allegations, and the 'evidence' usually ranges from half baked conspiracy theories to "expert testimony" without scientific basis.
The American Heart Association states that NONE of the artificial sweeteners causes any serious long term problems for most healthy adults
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On the other hand, while there is NO direct link to stroke and artificial sweeteners, studies do indicate that daily drinkers of diet soda (containing artificial sweeteners) are 36 percent more likely to develop metabolic syndrome and had an elevated risk of 67 percent for type 2 diabetes in comparison to those who don't drink it, according to a study authored by Jennifer A. Nettleton of the Division of Epidemiology at the University of Texas Health Sciences Center. Metabolic syndrome is a group of health conditions that put you at higher risk for diabetes, stroke and heart disease.
So there is an indirect connection between excessive artificial sweetener intake and stroke, though no direct one