Diet Soda and Dementia: What You Need to Know

A recent study found that drinking even one diet soda a day may triple your risk for developing dementia. But there's a lot more to the story. Nutrition Diva explains.

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #428

A study published last week in the journal Stroke found that drinking even one can of diet soda a day triples your risk of dementia. Not surprisingly, this caused quite an uproar.

Sharyn posted her concerns on the Nutrition Diva facebook page:

“I'm disturbed by a report I heard yesterday about a possible link between artificial sweeteners and dementia. I'm reluctant to stop using artificial sweeteners on the basis of a single study. I'm in my 60's and use artificial sweeteners daily. So sure, I'm concerned. Are there other studies that support this?”

As a matter of fact, Sharyn, there don’t seem to be any other studies linking artificial sweeteners to dementia. And I think your reluctance to change your behavior based on a single isolated finding is very reasonable—especially when we take a closer look at what this particular study actually found.

However, there may be other, more compelling arguments against daily consumption of artificial sweeteners. I’ll get back to those in a moment. For now, let’s take a look at what this most recent study does (and doesn’t) tell us about the relationship between artificial sweeteners and dementia risk.

Do artificial sweeteners cause dementia?

This is the first study to find a link between artificial sweeteners and dementia, mostly because this seems to be the first time researchers have looked for a connection between the two. I predict that this provocative finding will now prompt more researchers to ask the same question, which will shed a lot more light on the situation.

As it stands, the evidence that drinking diet soda may contribute to dementia risk is circumstantial, at best. This study simply observed that people who drink diet soda regularly are a lot more likely to eventually be diagnosed with Alzheimer’s disease or dementia.

However, further analysis found that those who drink diet soda are also more likely to be obese or have diabetes or heart disease. All of these conditions significantly increase your risk of developing Alzheimer’s disease. And if you are overweight or have diabetes, you might be more likely to drink diet soda because you’re trying to reduce your sugar or calorie intake. 

So the real question here is: Does drinking diet soda increase your risk of dementia any more than having diabetes or being overweight already does?

And sure enough, when the researchers adjusted the analysis to account for these other risk factors, the link between diet soda consumption and dementia essentially disappeared.

So, in this case, Sharyn’s skepticism is absolutely the right impulse. There’s very little in this study to suggest that drinking diet soda affects your risk of dementia. However, there are several other good reasons to reconsider your diet soda habit.

3 Reasons to Think Twice about Diet Soda

Reason #1: Artificial sweeteners may increase your risk of diabetes. This is pretty ironic because—as I just mentioned—people with diabetes often choose artificial sweeteners in order to reduce their consumption of sugar. Although the sweeteners themselves don’t cause an increase in your blood sugar, research has found that they may impair your body’s ability to process carbohydrates from other foods you eat.

You can read more about this research in episode #390 Do Artificial Sweeteners Promote Diabetes?

As I explained in that show, having a diet soda with your meal is not the same as having water with your meal. Even though both have zero sugar and calories, your blood sugar is likely to be higher after the meal with the diet soda. Over time, those higher blood sugar and insulin spikes can increase your risk of developing Type 2 diabetes, as well as lead to weight gain.


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.