Can Diet Soda Lead to Disease?

With regular sweetened soda containing up to 40 grams of sugar, many people switch to diet soda in hopes of reducing the harmful impact it has on their health. According to a new study, however, drinking diet soda may lead to its own problems, some of which are arguably worse than those of regular sweetened soda.

Researchers from the Boston University School of Medicine analyzed more than 2,800 men and women over the age of 44 and 1,400 plus men and women over the age of 59 for a period of 10 years. These participants were part of the Framingham Heart Study, which has been conducted since the 1970s. The purpose of this study was to determine whether or not the consumption of diet soda increased the risk of dementia and stroke.

So, what did they find? Researchers found that participants who consumed at least one diet soda per day were almost three times as likely to have a stroke caused by a blood vessel blockage. Furthermore, these same diet soda-drinkers were almost three times as likely to be diagnosed with dementia caused by Alzheimer's disease.

Commonly used artificial sweeteners in diet soda and other foods and beverages include saccharin, sucralose, neotame, acesulfame-K, and aspartame. However, the only artificial sweeteners used in this study were saccharin, acesulfame-K, and aspartame. Therefore, the others may not yield the same effects when consumed on a regular basis.

Does this mean that consuming diet soda will lead to stroke and/or dementia? Of course not, though these findings should certainly raise concern for "heavy drinkers" of artificially sweetened beverages.

"We need to be cautious in the interpretation of these results. It doesn't prove cause and effect. When you see these kinds of associations, you want to always ask what is the biological plausibility, what is the mechanism that might be causing this?" said Rachel K. Johnson, professor of nutrition at the University of Vermont.

What's even more interesting is that a separate study -- not conducted by these same researchers or in this same setting -- found no correlation between the consumption of regular sweetened soda and dementia and stroke. Therefore, only diet soda seems to trigger these health problems. The exact reason behind this phenomenon, however, remains to be seen. Researchers stress that these findings simply create a link between the two; there's no way of understanding how diet soda leads to stroke or dementia (not through this study at least).

This study was published in the journal Stroke.