_A preliminary study raised concern about diet soda and stroke risk. Researchers surveyed about 2,500 adults in the New York City area at the start of the study and followed their health for nearly 10 years afterward. Researchers found that people who said they drank diet soda every day had a 48 percent higher risk of stroke or heart attack than people who drank no soda of any kind. Researchers adjusted for differences in other risk factors, such as smoking and high blood pressure.
Lead researcher Hannah Gardener of the University of Miami had no explanation for the findings but said that for those trying to cut calories, "diet soft drinks may not be an optimal substitute for sugar-sweetened beverages."