People with the highest blood levels of the sugar substitute xylitol had a 57% higher rate of death, heart attack or stroke over six years than people with the lowest levels, according to research announced by the European Society of Cardiology on 26 August 2026 and presented at ESC Congress 2026. The analysis, led by Dr. Marco Witkowski of Charité University Hospital in Berlin, pooled 17,710 people from two long-running population studies and found the risk climbed step by step as blood xylitol rose.
Key takeaways
- In the Canadian cohort, the top quarter for blood xylitol had a 57% higher rate of death, heart attack or stroke over 6 years than the bottom quarter. In the British cohort, the gap was 18% over 30 years.
- The link held after accounting for age, sex, smoking, cholesterol, diabetes and high blood pressure.
- Xylitol was measured in blood, not on a food questionnaire, and the body makes its own xylitol from glucose. This is an unpublished conference abstract.
What the study found
The team analyzed data from the Canadian Longitudinal Study on Aging (CLSA) and the European Prospective Investigation into Cancer (EPIC)-Norfolk. Both are observational cohorts, meaning researchers tracked what happened to people rather than assigning anyone to consume xylitol.
The outcome was what cardiologists call a major adverse cardiovascular event, defined here as death, heart attack or stroke.
In CLSA, over six years of follow-up, people in the highest quarter of blood xylitol had a 57% higher rate of that combined outcome than people in the lowest quarter, after correcting for known cardiovascular risk factors including age, sex, smoking status, lipid levels, diabetes and high blood pressure. In EPIC-Norfolk, over 30 years, the gap was 18%. These are comparisons between the top and bottom quarters, not counts of events per 100 people.
Adding in the middle quartiles, the ESC said the pattern was dose-dependent: “the higher the xylitol blood levels, the higher the cardiovascular event rate.” The team reported the same direction of effect across age and sex.
Witkowski’s group has published earlier work showing xylitol can make platelets, the cells that start blood clots, more likely to clump, which gives the finding a plausible mechanism.
Dr. Kumar’s take
Every headline is running this as a sugar substitute story. The study did not measure sugar substitutes. It measured a molecule in blood.
That distinction carries a lot of weight, because your body manufactures xylitol on its own. The ESC release says it plainly: xylitol “occurs naturally in the body as a byproduct of glucose metabolism.” The route it takes is the polyol pathway, the same side road that converts excess glucose into sorbitol and related sugar alcohols. That pathway runs hardest when blood sugar is high and insulin is not working well. It is one of the mechanisms behind diabetic nerve and eye damage.
So a high blood xylitol level has two possible explanations. One is that a person is consuming a lot of it in gum, mints, protein bars, toothpaste and sugar-free baked goods. The other is that their own metabolism is churning it out because their glucose control is poor. Those two people have very different problems, and a blood test cannot tell them apart.
The researchers did adjust for diabetes, body mass index, blood pressure and lipids, which is a real point in the study’s favor. But a diabetes checkbox is a crude stand-in for insulin resistance. Plenty of people with rising blood sugar and high insulin never get the label. On that point Witkowski was direct: the association was independent of body mass index, hypertension, diabetes and lipid levels, the same measures that might push someone toward low-calorie products in the first place.
Two more things worth holding onto. This is a conference abstract, not a peer-reviewed paper, so the full methods are not yet available for scrutiny. And it is observational. As ESC Communication Committee member Professor Dan Atar put it, “causalities are difficult to infer.”
What it means for you
Nothing here justifies panic about your toothpaste. Xylitol has real dental benefits, and the amount you swallow from brushing is small.
If you eat a lot of xylitol-sweetened candy, gum or “keto” baked goods, moderating that is a low-cost decision while better evidence develops.
The more useful response is upstream. If the polyol pathway is part of this story, the intervention is better glucose control: less refined starch and sugar, more muscle, more walking after meals, and enough sleep. Those moves lower cardiovascular risk through channels that do not depend on this abstract holding up. Along the same lines, home blood pressure monitoring cut heart attacks by a third in one large analysis, and muscle quality, not size, predicts heart attack and death.
Swapping a sweetener is an easy action. Fixing the metabolism that may be generating the signal is the harder one, and probably the one that matters.