Do Diet Sodas Increase the Risk of Heart Disease and Stroke?

Do Diet Sodas Increase the Risk of Heart Disease and Stroke?

(Last Updated On: April 14, 2019)

diet sodas

Diet sodas sound like a healthier alternative to soft drinks. These fizzy beverages lack the sugar and high-fructose corn syrup that makes soft drinks so harmful. Instead, they’re sweetened with artificial sweeteners of various types, including aspartame and sucralose. So, what’s not to love about them? You sometimes hear that artificial sweeteners, like those used to sweeten soft drinks, increase the risk of cancer. Although there is no compelling evidence that they increase the risk of cancer in humans, you still might want to skip the diet soda. One concern is drinking them may increase the risk of cardiovascular disease.

Diet Sodas and Heart Disease: Is There a Link?

Where did the idea that sugar-free soft drinks are linked with cardiovascular disease come from? A new study conducted by the Australian Heart Foundation looked at the issue. During the study, they followed more than 80,000 women for 12 years. What they found was women who drank 2 or more servings of soft drinks daily had a 16% higher risk of stroke and cardiovascular disease.

The strengths of the study are that they followed a large number of women going forward rather looking back at their soft drink consumption habits in the past. The downside is this study doesn’t necessarily show that drinking sugar-free soft drinks caused a higher risk of stroke and cardiovascular disease. For example, people who drink sugar-free sodas may have some other trait in common that places them at higher risk. Still, it raises questions about the safety of drinking sugar-free soft drinks on a regular basis.

Drinking sugar-sweetened soft drinks is also linked with cardiovascular disease and stroke. In fact, drinking only one soda daily is associated with a 20% higher risk of having a heart attack. One explanation might be the added sugar in non-diet sodas. A diet high in sugar raises blood sugar and increases the risk of type 2 diabetes and obesity. Sugar-sweetened sodas also increase blood triglycerides and inflammatory markers, both of which are harmful to the heart and blood vessels.

But, why would diet soft drinks be linked with cardiovascular disease? Some studies suggest that diet sodas might increase the risk of obesity by causing people to eat more. When you drink a soft drink, your body expects calories to follow. If they don’t, your body still senses an energy deficit, and this triggers the desire to consume more calories. Some research also suggests that artificial sweeteners change the gut microbiome in a way that makes obesity more likely. But further scrutiny of these studies shows that other factors like lifestyle and dietary habits weren’t well controlled for. It’s not clear whether diet soft drinks trigger overeating or increase weight gain as sugar-sweetened soft drinks do.

So, how can you explain a possible link between diet sodas and cardiovascular disease? Although sugar-free soft drinks don’t cause the same rise in blood sugar that sugar-sweetened beverages do, a number of studies suggest they increase the risk of metabolic syndrome, a precursor to type 2 diabetes. Drinking diet sodas is linked with an increase in some markers of metabolic health and cardiovascular risk. In addition, a review of several studies showed that each can of diet soda individuals consumed boosted their risk of type 2 diabetes by 13%.

What complicates things is people who drink diet soft drinks often do it to compensate for a high-calorie meal or poor eating habits. Have you ever seen someone order a Big Mac, fries, and a diet cola? It’s more common than you think! People who do this are more likely to have other bad health habits and health issues that increase their risk of heart attacks and stroke. Could that be the explanation? Possibly. Yet a study published in Journal of General Internal Medicine found a higher risk of stroke and heart attack in diet soda drinkers even when they controlled for health problems, like high blood pressure, elevated cholesterol, and type 2 diabetes.

How Might Diet Sodas Cause Heart Disease?

Unfortunately, scientists don’t know why there’s a link between drinking diet sodas and heart disease. The lack of a mechanism makes it harder to say whether the association between the two is causal. Research suggests that energy drinks impair blood vessel function in a way that increases the risk of acutely experiencing heart issues, but energy drinks have higher levels of caffeine and other ingredients that cause blood vessels to constrict. You can’t say that soft drinks have the same effects on the heart and blood vessels as energy drinks since energy drinks contain other ingredients, including stimulants.

Why It’s Still Best to Stay Away

If a possible link between drinking diet sodas and cardiovascular disease doesn’t scare you, maybe this will. When researchers looked at the results of the Framingham Heart Study, they found subjects who drank at least one diet soda daily, were 2.89 times more likely to be diagnosed with Alzheimer’s dementia and 2.96 times more likely to suffer from an ischemic stroke. An ischemic stroke is due to narrowing or blockage of an artery that delivers blood to the brain. Again, this study doesn’t show cause and effect, but it does raise concerns about how artificially sweetened beverages impact heart, blood vessel, and brain health.

The Bottom Line

Diet soft drinks offer no nutritional value. Despite their lack of sugar and calories, there are concerns they may be harmful to your heart and blood vessels. Don’t drink sugar-sweetened ones either! A better alternative is to drink water flavored with slices of fruit or unsweetened tea. If you crave carbonation, try seltzer water instead. You’ll get the fizz without the artificial sweeteners!



·        Stroke. “Artificially Sweetened Beverages and Stroke, Coronary Heart Disease, and All-Cause Mortality in the Women’s Health Initiative” February 14, 2019.

·        Circulation. 2007 Jul 31;116(5):480-8. Epub 2007 Jul 23.

·        Diabetes Care. 2009 Apr;32(4):688-94. doi: 10.2337/dc08-1799. Epub 2009 Jan 16.

·        J Gen Intern Med. 2012 Sep;27(9):1120-6. doi: 10.1007/s11606-011-1968-2. Epub 2012 Jan 27.

· “Is Drinking Diet Soda a Health Risk?”

·        Science Daily. “Just one energy drink may hurt blood vessel function”

·        American Heart Association. “A diet soda a day might affect dementia risk, study suggests”


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