Considered for years a beneficial alternative to sugar, xylitol has found its way into chewing gum, candies, “sugar-free” products, supplements, and oral hygiene products. It contains fewer calories than sucrose and causes a smaller increase in blood glucose…
For years, xylitol was considered a beneficial alternative to sugar and has found its way into chewing gum, candies, “sugar-free” products, supplements, and oral hygiene products. It contains fewer calories than sucrose, causes a smaller increase in blood glucose, and, most importantly, is not easily used by the bacteria responsible for tooth decay.
However, more recent scientific literature has raised an unexpected question: high concentrations of xylitol in the blood could make platelets more reactive and promote clot formation, potentially increasing the risk of heart attack and stroke.
It has not yet been proven that chewing xylitol gum directly causes a cardiovascular event. But a series of international studies, culminating in a new analysis of more than 17,000 people, suggests that the long-term safety of this sweetener deserves further investigation.
It is not technically an artificial sweetener
Xylitol belongs to the family of polyols, also known as sugar alcohols. It occurs in very small amounts in some plants and is also produced by the body as a by-product of glucose metabolism.
The xylitol added to foods, identified in Europe by the designation E967, is instead produced through industrial processes and can reach quantities vastly higher than naturally occurring concentrations.
It is therefore inaccurate to simply call it an “artificial sweetener.” The concern raised by the studies does not involve the trace amounts of xylitol naturally present in fruit or produced by the body, but primarily exposure to the concentrated doses used in sugar-free products.
For a long time, attention focused mainly on its intestinal effects. High doses can draw water into the intestine and cause bloating, cramps, flatulence, and diarrhea. In recent years, however, research has shifted toward its possible relationship with thrombosis.
The first warning sign: more cardiovascular events over three years
The study that sparked the debate was published in 2024 in the European Heart Journal by Marco Witkowski, Stanley Hazen, and colleagues from the Cleveland Clinic and Charité in Berlin.
The scientists initially analyzed the blood of 1,157 people undergoing cardiac evaluations. The findings were then verified in a second, independent cohort of 2,149 participants.
In the validation group, people with the highest plasma concentrations of xylitol had a 57% higher risk of cardiovascular death, heart attack, or stroke than those with the lowest levels during three years of follow-up. The association remained significant after adjustment for several risk factors.
An observational finding alone, however, does not demonstrate a cause-and-effect relationship. People with diabetes, obesity, or cardiovascular disease may consume more sugar-free products. Moreover, the xylitol measured in the blood does not necessarily come solely from food: it can be produced by the body itself and may, at least in part, be a marker of an already altered metabolism.
The platelet experiment
To investigate causality, the researchers also conducted experiments using human platelets, whole blood, and animal models. Under these conditions, xylitol increased several measures of platelet activation and accelerated the formation of blood clots.
A small test was also conducted on ten healthy volunteers. After consuming a beverage containing 30 grams of xylitol, their plasma levels of the polyol rose rapidly, and their platelets showed increased reactivity.
The proposed mechanism is therefore biologically plausible: platelets that are more sensitive to stimuli may aggregate more easily. If a clot blocks a coronary artery, a heart attack can occur; if it blocks a blood vessel in the brain, it can cause an ischemic stroke.
The study did not, however, demonstrate that normal daily consumption produces the same effect. Thirty grams in a single dose represents a high exposure, far greater, for example, than the amount contained in a single piece of chewing gum.
The objections: blood levels could be a marker
Some members of the scientific community have urged caution in interpreting the findings. In a commentary published in the European Heart Journal in 2025, researchers noted that the initial cohorts consisted largely of people who were already at elevated cardiovascular risk.
Endogenous xylitol is produced through the pentose phosphate pathway, a metabolic pathway that can become more active in the presence of ischemia, oxidative stress, and metabolic abnormalities. Elevated concentrations could therefore be not only a consequence of dietary consumption but also a sign of an underlying disease.
In other words, “reverse causality” remains possible: it may not necessarily be xylitol that makes people ill; rather, impaired metabolism could cause circulating xylitol levels to rise.
The authors of the critique also pointed out that the amounts normally used for cavity prevention are much lower—often around 5–6 grams per day, divided into several doses. A piece of chewing gum generally contains less than one gram.
The benefits for oral health are not erased
Xylitol remains a useful ingredient in dentistry. It is not readily fermented by cavity-causing bacteria, promotes saliva production, and may help reduce the demineralization of tooth enamel.
This does not mean that every product containing xylitol automatically prevents cavities: the amount, frequency of use, formulation, and overall quality of oral hygiene all matter. However, the literature documents potential benefits, particularly for chewing gum and products used after meals.
The new cardiovascular hypothesis does not erase this evidence. Rather, it makes it important to determine whether there is a threshold beyond which a local benefit for the teeth and gums might be accompanied by undesirable systemic effects, particularly in patients who are already vulnerable.
It should also be clarified that the World Health Organization's 2023 recommendation against routinely using non-sugar sweeteners for weight control did not include polyols such as xylitol. That guideline, moreover, was not a toxicological review of individual additives and did not establish new maximum safe doses.
The new analysis of more than 17,000 people
Further support for the signal has now come from research coordinated by Marco Witkowski, which is due to be presented on August 29 at the 2026 Congress of the European Society of Cardiology in Munich.
The group examined 17,710 participants from two large prospective studies: the Canadian Longitudinal Study on Aging and the British EPIC-Norfolk study. Compared with the earlier research, the analysis involved larger populations and much longer follow-up periods.
In the Canadian cohort, over six years of follow-up, people in the quartile with the highest blood xylitol levels had a 57% higher risk of death, heart attack, or stroke than those in the lowest quartile.
In the EPIC-Norfolk study, which followed participants for up to 30 years, the relative increase in risk was 18%. Data from the intermediate quartiles also suggest a dose-response relationship: as circulating xylitol increased, so did the frequency of cardiovascular events.
The association persisted after adjustments for age, sex, smoking, body mass index, hypertension, diabetes, and blood lipid levels.
The results therefore extend the 2024 signal to a general population and over longer periods. But they do not settle the debate: these are still observational cohorts and, at present, the findings have been released ahead of a conference rather than as a complete scientific publication that has undergone the usual peer-review process.
What consumers should do
There is not enough evidence to recommend that everyone immediately eliminate every chewing gum or toothpaste containing xylitol. Exposure through an oral hygiene product, which is generally not swallowed, is different from daily consumption of beverages, sweets, powders, and heavily sweetened foods.
Greater caution may be reasonable for people who consume large amounts of “sugar-free” products, use powdered xylitol as a substitute for sugar, or already have heart disease, diabetes, a history of thrombosis, or a high cardiovascular risk. In these cases, it is advisable to check product labels and discuss regular use of concentrated sweeteners with a doctor or nutritionist.
Above all, xylitol should not become an excuse for maintaining a diet dominated by sweet flavors. The most robust strategy is not to automatically replace every gram of sugar with another sweetener, but to gradually reduce the habit of consuming very sweet foods and drinks.
The new study does not yet deliver a definitive verdict. It does, however, shift the burden of proof: after decades in which polyols have been considered primarily from metabolic, dental, and intestinal perspectives, their effects on platelets, blood clots, and arteries now also need to be evaluated.
Essential bibliography
Witkowski M. et al. “Xylitol is prothrombotic and associated with cardiovascular risk,” European Heart Journal, 2024. Original study.
European Society of Cardiology. “Xylitol may increase the risk of cardiovascular events,” communication on the ESC Congress 2026 study. New research data.
Valentine G.C. et al. “Oral health benefits and safety of xylitol and potential cardiovascular risk,” European Heart Journal, 2025. Critical commentary.
World Health Organization. “Use of non-sugar sweeteners: WHO guideline,” 2023. Guideline.
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