A: Sometimes it seems like people trying to choose a healthy diet and watch their weight can’t catch a break.
Past studies have linked the consumption of sugar-sweetened drinks with cardiovascular disease, high blood pressure and obesity. So it’s easy to understand the appeal of diet soft drinks and other artificially sweetened beverages. If you drink two cans of Coke per day, switching to diet sodas could reduce your calorie intake by 8,400 calories each month.
But a new study has raised the possibility that artificial sweeteners in diet beverages may increase the risk of dementia and stroke.
Researchers analyzed health data from nearly 3,000 adults who had filled out diet surveys, and determined their incidence of stroke or dementia over 10 years. Compared with people who said they didn’t consume diet drinks, those who had at least one per day suffered three times more strokes, and were three times more likely to develop dementia.
Before you despair or give up your favorite diet beverage forever, keep in mind that a study of this sort has some major limitations that can lead to faulty conclusions. For example, the researchers may have missed an important factor that influenced the results. Perhaps the people who chose sugar-free soft drinks because they had pre-diabetes or a genetic predisposition to having a stroke or dementia.
In addition, this type of study cannot establish cause and effect. Even if there is a higher rate of brain disease in people who drink more diet soft drinks, we can’t be sure that the diet soft drinks were the cause.
This study did not look at the overall health effects of diet soft drinks. It’s possible they are still a healthier choice than sugar-sweetened beverages.
It’s also important to note that the study was based on surveys done a while back and did not look at the specific artificial sweeteners used in the beverages. So it’s possible that drinks with newer artificial sweeteners, such as sucralose, might lead to different results.
I have to admit, this study has made me rethink my own habits. Would it be better if I started adding sugar to my coffee rather than my current routine of adding sucralose? I’m not sure. And this study gives me no guidance.
But if you drink a lot of diet soft drinks, this study should give you pause — maybe moderation is in order. Or maybe drinking plain water wouldn’t be such a bad idea.
(Robert H. Shmerling, M.D., is Associate Professor of Medicine at Harvard Medical School and Clinical Chief of Rheumatology at Beth Israel Deaconess Medical Center in Boston. For additional consumer health information, please visit www.health.harvard.edu.)
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Erin O’Donnell is a freelance health and science writer, parent, and graduate of Northwestern’s Medill School of Journalism. Walks by Lake Michigan make her happy.