For two years, Finnish scientists asked a group of folks to do something pretty extreme...
They replaced virtually all of the sugar in their diet with something else... xylitol.
You know it as the sugar substitute that's in everything from breath mints and chewing gum to baked goods.
University of Turku researchers wanted to know how the sweetener would affect participants' teeth. And what happened seemed almost like magic... It appeared to improve some of the participants' cavities.
The experiment was one of several in what are now called the Turku Sugar Studies, published in 1975. This research helped turn xylitol into a darling of the dental-health world.
Xylitol's reputation still holds up... According to a 2025 systematic review in BMC Oral Health, xylitol chewing gum reduced levels of cavity-causing bacteria in 12 out of 14 studies, compared with sorbitol gum. It also reduced plaque buildup in 6 out of 10 studies and cavity occurrence in 3 out of 5 trials.
And just this past July, another systematic review focused on older folks and people with disabilities found that xylitol gum or candies significantly reduced dental plaque. In frail older adults, chewing xylitol gum was also found to help with dry-mouth symptoms by increasing saliva production.
But don't dump a spoonful in your coffee just yet... That's because, more than 50 years after those original Finnish experiments, scientists have started asking an entirely different question about xylitol...
Xylitol Could Be Harming Your Heart
That question is what xylitol could be doing to the heart...
In a June 2024 study published in the European Heart Journal, researchers measured fasting blood-xylitol levels in more than 3,000 participants who were undergoing evaluation of cardiovascular health. Folks with the highest blood-xylitol levels were more likely to suffer a major adverse cardiovascular event ("MACE") like a heart attack, a stroke, or death over the next three years.
That was only using levels already circulating in the blood. But the researchers also wanted to account for the fact that the human body can make xylitol on its own. (Basically, when your body processes glucose, or blood sugar, a small amount gets converted into xylitol.)
Participants had fasted overnight for at least 12 hours before blood was drawn. This suggested that much of the xylitol levels measured came from participants' own naturally produced xylitol.
To check the impact of consuming xylitol, researchers included a separate, small experiment where 10 healthy volunteers drank water sweetened with 30 grams of xylitol. Blood-xylitol levels soared and then dropped back near baseline levels within about four to six hours.
Also concerning was that after downing their xylitol waters, participants' blood platelets (which are important for blood clotting) became more reactive.
Fast-forward to last month, and xylitol made headlines again...
A study presented at the European Society of Cardiology's annual meeting found another connection between xylitol and heart health. The study measured blood-xylitol levels in 17,710 Canadian and European participants.
In the Canadian group, participants with the highest blood-xylitol levels had a 57% higher risk of suffering a MACE like a heart attack, a stroke, or death over a six-year time frame. That was compared with those who had the lowest blood-xylitol levels. And in the European group, the highest-level group had an 18% greater risk over 30 years.
In short, the higher the xylitol levels, the higher the MACE rate... And that association held up even after accounting for other variables like age, smoking status, diabetes, high blood pressure, and cholesterol.
Now, keep in mind... This study measured the levels of xylitol circulating in the blood, not dietary consumption. Plus, these findings have not yet been published in a peer-reviewed journal.
My take? It's a warning signal worth keeping an eye on, but no reason to panic. Here's what I recommend you do...
It's All About Moderation
Longtime readers know I'm no fan of eating lots of added sugars. At the same time, loading up on sugar-free foods isn't the answer, either.
If you chew xylitol gum for your teeth – and especially if you're prone to cavities – I wouldn't chuck it out just yet. It definitely does have well-studied oral-health benefits.
Plus, you really don't need all that much xylitol to reap the rewards for your teeth... According to the BMC review, about 5 to 6 grams of xylitol a day, spread over at least three doses, seems to be effective in reducing those cavity-causing bugs and plaque. So, no need to shovel spoonfuls of it into your coffee or bake with a ton of it.
P.S. One of my favorite events of the year is coming up fast... the 24th annual Stansberry Conference & Alliance Meeting. This is no ordinary conference. It's a place to hear from world-class speakers and discover new investment opportunities from top experts. And for a limited time, you can get a discounted livestream ticket – so you can experience the most powerful financial event of 2026 without leaving your living room.
What We're Reading...
- Did you miss it? Artificial sweeteners aren't the "healthy" answer to sugar.
- Something different: The best – and award-winning – way to blow your nose.
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
September 10, 2026