Does drinking diet soda raise the risk of a stroke?

Julie Corliss
Julie Corliss, Executive Editor, Harvard Heart Letter

For diet soda fans, recent news reports linking these popular drinks to higher risk of stroke may have been alarming. A closer look at the study behind the headlines suggests there’s no need to panic. But beverages naturally low in calories are probably a healthier option than artificially sweetened drinks.

The study included 2,888 people ages 45 and older from the long-running Framingham Heart Study, all of whom filled out diet questionnaires up to three times over a seven-year period. People who said they drank at least one artificially sweetened soda a day were about twice as likely to have a stroke over the following decade when compared to those who drank less than one a week. Drinking regular, sugar-sweetened sodas or beverages did not appear to raise stroke risk.

However, these types of studies can’t prove cause and effect, only an association. Also, only 97 people (3%) had strokes during the follow-up, which means only two or three of those strokes could possibly be attributed to drinking diet soda, says Dr. Kathryn Rexrode, an associate professor of medicine at Harvard-affiliated Brigham and Women’s Hospital who co-authored an earlier, larger study looking at soda consumption and stroke risk.

Stroke risk from all sodas?

That study detected a slightly higher risk of stroke in people who drank more than one soda per day, regardless of whether it contained sugar or an artificial sweetener. Although the latest study didn’t detect a higher stroke risk from sugary beverages, that certainly doesn’t suggest they are a better choice than diet sodas. Many studies have already shown that drinking sugary beverages on a regular basis can lead to weight gain, diabetes, high blood pressure, heart disease, and stroke, she notes.

Possible explanations

In fact, one possible explanation why sugary beverages weren’t linked to stroke in the recent study might be a phenomenon known as survival bias. In this case, that would mean that people who drank a lot of sugar-sweetened beverages may have died earlier from other illnesses such as heart disease.

Conversely, diet beverages may have shown a link to stroke because of a different issue, called reverse causation. In an attempt to be healthier, people who are overweight or have diabetes may be more likely to choose diet drinks over sugary ones. Their heightened stroke risk may result from their health problems rather than their beverage choice. “We might just be measuring the residual impact of obesity and diabetes,” says Dr. Rexrode.

Artificial sweeteners: Other shortcomings

Another conundrum: researchers don’t have any plausible explanation for why artificial sweeteners might increase stroke risk. Still, there may be other reasons to ditch them.

If you use artificial sweeteners to control your weight, you should know that the support for that strategy is pretty shaky. Some evidence suggests that artificial sweeteners make people crave sugary, high-calorie foods, thereby negating the sweetener’s potential to cut your overall calorie intake. And some experts believe that people who use these high-intensity sweeteners (which are hundreds of times sweeter than sugar) may come to find naturally sweet foods, such as fruit, less appealing and less-sweet foods, such as vegetables, downright unpalatable. If so, those people might be missing out on the many heart-protecting nutrients found in fresh, natural foods.

But Dr. Rexrode isn’t a stickler when it comes to diet soda. “I encourage my patients to eliminate regular soda and other sugar-sweetened drinks to avoid empty calories,” she says. “But if someone says they can’t do without a Coke in the morning to wake up, I’ll encourage them to switch to coffee or diet Coke.” Water is an even better choice, however. “There are a lot of ways to make it more appealing, both visually and taste-wise.” she adds. Try flavoring flat or sparkling water with a splash of fruit juice, or add frozen fruit, cucumber, or crushed mint.

Comments:

  1. Michael Crayne

    Though circumstances might be overwhelming, they can be overcome with diligent effort and a little bit of elbow grease. MC.

  2. mary Stephanie nix

    You guys are awesome! Being me and having to deal with me, I raise my glass of water with a slice of orange in it to you awesome creatures who possess self control when confronted with unlimited 0 calorie drinks that taste terrific😆

  3. mary Stephanie nix

    My Dad, a BC grad, used to say, “Everything! In moderation!” My Dad left the earth in 1959 after a fight with cancer. But his words are always in my brain. My question is this: Having become totally enamored with a certain diet drink which has no calories but plenty of caffeine! I found I was glugging down can after can after can especially when I could buy lots of cartons on sale! FREE I thought! But ah, beware, there is a price methinks, a tad worse than my usual caffeine from coffee, as there is a pairing with plenty of sodium! So, at 73, and still working, I am cutting out ALL sodas and most coffee and switching to water and an occasional orange and am already feeling better! Any compatriots out there?

  4. Stephanie

    I often see the claim that artificial sweeteners “make people crave” more sweets. Is there any scientific basis for this claim?

    It does not agree with my personal experience at all. I drink a diet soda almost daily during the summer (and perhaps monthly other times of year). I notice no such “cravings” when I drink a lot of diet soda. I’ve maintain a healthy weight for 30 years by counting calories, and sugar sweetened soft drinks aren’t worth the 150 calories to me. I’d rather eat something with those calories. But I do enjoy diet sodas when its hot out, with no perceptible ill effects.

  5. joe

    science has shown artificial sweetners are fine in moderate amounts

  6. Osei Bright Steve

    OK, so that means drinking soda is not a major cause of stroke but it’s rather associated with it some how.