Is Xylitol Bad for Your Heart? What the New Study Does and Doesn't Show

September 1, 2026

If you chew sugar-free gum, brush with a sweetened toothpaste, or keep keto-friendly candy in a drawer, you probably saw a headline last week telling you it might give you a stroke. The story ran on Newsweek, in the Washington Times, and across a few hundred radio station websites over a single weekend. Coverage like that travels a great deal faster than the study behind it, and the question tends to arrive before the paper does.

The study is real and the researchers are serious people. The finding is weaker than the headline, and there is a scientific argument underneath it that almost none of the coverage mentioned. That argument is the part worth your attention, and one piece of it points fairly strongly the other way.

What was presented

At the European Society of Cardiology meeting in Munich on August 29, Dr. Marco Witkowski of Charité University Hospital in Berlin reported an analysis of two long-running population studies. Together they included 17,710 people, one group followed in Canada and one in the United Kingdom.

The researchers measured xylitol in stored blood samples, sorted people into four groups from lowest to highest, and counted how many went on to die, have a heart attack, or have a stroke. In the Canadian cohort, followed about six years, the highest quarter had roughly 57 percent more of those events than the lowest quarter after accounting for the usual risk factors. In the British cohort, followed about thirty years, the gap was about 18 percent. Risk climbed step by step across the middle groups rather than jumping only at the top.

Witkowski’s own summary was not a warning. He said the findings show how little is known about the cardiovascular safety of xylitol and that further study is warranted. A member of the ESC communications committee added the standard caution that causality is hard to pin down in a study of this design. Neither of those lines made the headlines.

The study before this one

This is not the first time xylitol has come up. In 2024 the same researcher, working with Dr. Stanley Hazen’s group, published a paper in the European Heart Journal that did three things at once.

They screened blood from 1,157 stable patients coming in for cardiac testing and found a polyol that tracked with heart attacks, strokes, and death over three years. They confirmed it was xylitol using a more precise method in a separate group of 2,149 patients, where the top third carried about a 57 percent higher risk than the bottom third after adjustment. They then ran laboratory work showing xylitol made platelets, the cells that start a clot, more reactive. Finally they gave ten healthy volunteers a xylitol-sweetened drink and found that blood levels rose sharply within half an hour, with measurable changes in platelet behavior in every subject.

Laid out that way it sounds close to airtight. An association in people, a mechanism in the lab, and a human experiment showing the mechanism switches on after you drink the stuff. That is the shape of a convincing argument.

Why the measurement is contested

Your body makes xylitol on its own. It is a normal intermediate in a metabolic pathway that runs in everyone, whether or not they have ever chewed a stick of gum. So a blood level is a mix of what you made and what you ate, and the two cannot be told apart in a stored sample.

Which source dominates is disputed, and not as a matter of politeness. The Witkowski group’s position is that levels reached after eating polyol-sweetened products run more than a thousand times higher than what the body produces on its own, so a high reading should mostly reflect diet. Critics writing to the same journal argued the opposite for these particular cohorts, since the blood was drawn fasting and many participants were enrolled before sugar alcohols became common in processed food. On that reading, the study would be telling us that people who make more xylitol internally have more heart attacks, which is a finding about metabolism rather than about the candy aisle.

The fair summary is that fasting levels probably capture both, and that none of these studies measured what anyone actually ate. Unmeasured diet is the central limitation, and it applies to every result in this line of work.

The critics raised other points. The ten-volunteer experiment had no placebo group and measured a single time point. Sugar alcohols given intravenously to critically ill patients, at doses far above anything in a diet, have not produced a documented wave of clotting events. And at least one 2025 laboratory study found xylitol reduced oxidative stress in immune cells exposed to LDL, which is the opposite of a harmful effect.

What the genetic evidence says

There is a way to test causation without running a trial, and it has been done for the closely related sweetener erythritol.

The method uses gene variants that nudge a person’s lifelong levels of a substance up or down. Because those variants are assigned at conception and do not shift with diet, income, or illness, they sidestep most of the confounding that observational studies struggle with. If higher levels of a substance cause heart disease, people carrying the variants for higher levels should get more of it.

For erythritol, they did not. A 2023 study in Diabetes using this approach found no support for a causal effect on coronary artery disease. That is the single strongest piece of counter-evidence in this area, and a 2025 review in Cardiovascular Research leaned on it in framing the whole question as unresolved, titling the piece “friend or foe.”

Nobody has run the equivalent analysis for xylitol itself. Erythritol is not xylitol. The two behave similarly enough, and were flagged by the same laboratory using the same design, that a negative causal test for one is worth knowing about when you read the headlines about the other.

Where the whole body of evidence sits

A systematic review published this year pooled eleven studies of blood polyol levels and found about a 26 percent higher rate of cardiovascular events comparing the highest exposure category to the lowest. Two things about that result deserve equal billing. The studies disagreed with each other a great deal, and the authors found signs of publication bias, which is the pattern you see when studies showing nothing quietly fail to get published. The same review found no clear link between how much sweetener people reported eating and cardiovascular death.

So the association shows up repeatedly in blood levels and does not show up in diet. That is exactly the pattern you would expect if blood polyols were partly a marker of something else going on in the body. It is also, to be fair, what you would see if food-frequency questionnaires are simply too crude to capture sweetener intake, which they probably are.

What this means for your gum

A few practical points, in the order I would raise them.

The dose in dental products is small. A piece of chewing gum carries roughly 1.3 grams of xylitol, a mint or lozenge about 1 gram, a mouthrinse about 1 gram, and toothpaste around 0.1 gram per brushing, most of which is spat out. The cardiovascular experiments used a single large drink, in the range of 30 grams, enough to spike blood levels hard and fast. Someone chewing a couple of pieces of gum a day is nowhere near that.

The exposure worth thinking about is processed food. Keto baking mixes, sugar-free syrups, protein bars, and sugar-free candy eaten by the handful are where grams add up quickly. Xylitol also turns up as an inactive filler in tablets, in small and mostly unavoidable amounts.

The dental benefit is real and more modest than the marketing suggests. A Cochrane review of ten studies in 5,903 people rated most of the evidence low quality. The clearest finding was that a toothpaste with 10 percent xylitol added to fluoride reduced cavities by about 13 percent over two and a half to three years compared with fluoride alone. Most other comparisons were inconclusive. So there is something there, and it is not the sweeping benefit implied on the packaging. Worth noting on the other side, the most common problem xylitol actually causes is gastrointestinal, meaning bloating, gas, and diarrhea at higher intakes.

What would settle this is a study that tracks what people eat over years and follows their hearts, or a randomized trial with cardiovascular outcomes. Neither exists. Regulators in the United States and Europe still treat xylitol as safe, it carries the additive number E967 in Europe, and no cardiology or nutrition society has issued a position restricting it. Some editorial writers have argued that its safety designation deserves another look, and I think that request is reasonable.

Until then, xylitol sits in the same category as calcium supplements, where a signal appeared in observational data and the right response was to think about food first and not to panic. The coffee question followed a similar arc and settled in a similar place.

If you have already had a heart attack or stroke, or you take a blood thinner, raise it at your next visit, whether that is with me here in Encinitas or with your own cardiologist. I am not telling you the risk is established. You are simply the person for whom a small clotting effect would be worth avoiding while the question stays open, and you should be reviewing the whole diet anyway. A Mediterranean pattern has evidence behind it that no sweetener can match.

For everyone else, the reasonable move is the boring one. Cut back on the products where sugar alcohols show up by the gram, keep the gum if you like it, and do not let a sweetener question distract from the things that actually drive coronary artery disease, which are blood pressure, LDL cholesterol, blood sugar, smoking, and how much you move.

Frequently Asked Questions

Should I throw out my sugar-free gum?

No. A piece of gum contains about 1.3 grams of xylitol and toothpaste about 0.1 gram per brushing, far below the roughly 30 grams used in the experiments that produced the clotting effects. If you want to reduce exposure, start with keto baking mixes, sugar-free syrups, and sugar-free candy eaten in quantity, where the amounts are much larger.

Does this study prove xylitol causes heart attacks?

No. It is an observational study, which can show that two things travel together and cannot show that one causes the other. The two groups studied also disagreed considerably on the size of the effect, 57 percent higher risk over six years in one and 18 percent over thirty years in the other. The presenting researcher called for further study rather than for people to stop using it.

Why do some experts say the blood test does not measure what you eat?

The body produces xylitol on its own as part of normal metabolism, so a blood level combines what you made with what you ate. The researchers argue that eating polyol-sweetened products raises levels more than a thousandfold above what the body makes, so diet should dominate. Critics counter that these samples were drawn fasting, in cohorts recruited before sugar alcohols were common in food, so the readings likely reflect internal production. None of the studies recorded what participants actually ate, which is the central limitation.

Has anyone tested whether this is cause or coincidence?

For the related sweetener erythritol, yes. A 2023 study used inherited gene variants that raise or lower lifelong levels, an approach that avoids most of the confounding in ordinary observational research, and found no support for a causal effect on coronary artery disease. The equivalent analysis has not been published for xylitol.

Is erythritol the same situation?

It is a closely related story from the same research group, with the same design. Blood erythritol was associated with heart attacks and strokes in two validation groups, and a study in healthy volunteers found that 30 grams of erythritol, but not the same amount of glucose, raised blood levels sharply and increased platelet activity. The genetic analysis described above is the main reason for caution about reading those findings as cause and effect.

What about xylitol in my toothpaste or my medications?

Toothpaste carries around 0.1 gram per brushing and is mostly spat out. Xylitol also appears as an inactive filler in many tablets, where the quantities are small and generally unavoidable. Neither is where a person concerned about this should start.

What should I do while this gets sorted out?

Reduce the large-dose sources if it is easy to do. Keep the attention on the risk factors with settled evidence behind them, meaning blood pressure, LDL cholesterol, blood sugar, tobacco, and physical activity. If you have had a heart attack or stroke or you take a blood thinner, mention it at your next appointment.

References

1. Witkowski, Marco, Ina Nemet, Xinmin S. Li, et al. “Xylitol Is Prothrombotic and Associated with Cardiovascular Risk.” European Heart Journal 45, no. 27 (2024): 2439-2452.

2. European Society of Cardiology. “Xylitol May Increase the Risk of Cardiovascular Events.” Press release, ESC Congress 2026, Munich, August 29, 2026.

3. Gimeno-Ruiz, Sandra, Carmen Torrijo-Belanche, Ainara Muñoz-Cabrejas, et al. “Artificial Sweeteners and Cardiovascular Disease: Systematic Review and Meta-Analysis.” Nutrition Reviews (2026).

4. Khafagy, Rana, Satya Dash, and Andrew D. Paterson. “Erythritol as a Potential Causal Contributor to Cardiometabolic Disease: A Mendelian Randomization Study.” Diabetes 72, no. 12 (2023).

5. Wölnerhanssen, Bettina K., Anne Christin Meyer-Gerspach, Arduino Arduini, et al. “Sweeteners: Erythritol, Xylitol and Cardiovascular Risk, Friend or Foe?” Cardiovascular Research (2025).

6. Witkowski, Marco, Ina Nemet, Hassan Alamri, et al. “The Artificial Sweetener Erythritol and Cardiovascular Event Risk.” Nature Medicine 29 (2023): 710-718.

7. Witkowski, Marco, Jennifer Wilcox, Valentin Province, et al. “Ingestion of the Non-Nutritive Sweetener Erythritol, but Not Glucose, Enhances Platelet Reactivity and Thrombosis Potential in Healthy Volunteers.” Arteriosclerosis, Thrombosis, and Vascular Biology (2024).

8. Riley, Philip, Deborah Moore, Farooq Ahmed, Mohammad O. Sharif, and Helen V. Worthington. “Xylitol-Containing Products for Preventing Dental Caries in Children and Adults.” Cochrane Database of Systematic Reviews (2015).

9. Lif Holgerson, Pernilla, Christina Stecksén-Blicks, Ingegerd Sjöström, and Marie Öberg. “Xylitol Concentration in Saliva and Dental Plaque after Use of Various Xylitol-Containing Products.” Caries Research 40, no. 5 (2006): 393-397.

10. Miller, Michael, Monica Aggarwal, Kathleen Allen, et al. “A Clinician’s Guide for Trending Cardiovascular Nutritional Controversies in 2026.” JACC: Advances (2026).

11. Huang, Zhiwei, Ang Li, Rui Huang, et al. “Effect of Xylitol on Low-Density Lipoprotein-Stimulated Oxidative Stress in THP-1 Cells.” Molecular Medicine Reports (2025).

12. Debras, Charlotte, Eloi Chazelas, Laury Sellem, et al. “Artificial Sweeteners and Risk of Cardiovascular Diseases: Results from the Prospective NutriNet-Santé Cohort.” BMJ 378 (2022): e071204.

Published on damianrasch.com. The above information was composed by Dr. Damian Rasch, drawing on individual insight and bolstered by digital research and writing assistance. The information is for educational purposes only and does not constitute medical advice.