Sugar-Free Gum Linked to Heart Risk
- A study of 17,710 people presented at the ESC congress in Munich found high blood xylitol levels associated with a 57% rise in heart attack, stroke, and cardiovascular death risk
- The observational study cannot prove causation; researchers say metabolic confounders may partly explain the link, and xylitol retains its regulatory classification as safe.
- Study author Dr Marco Witkowski says further research is urgently needed as xylitol appears in an increasing number of food and diet products.
Millions of people who reach for a sugar-free chewing gum after a meal may be unknowingly exposing themselves to elevated cardiovascular risk, according to research presented on Saturday at the European Society of Cardiology congress in Munich — described as the world's largest cardiology conference. The study, conducted by scientists from Germany, Canada, and the United Kingdom, analysed data from 17,710 participants across two large long-term studies and found a significant association between high blood levels of xylitol and an increased risk of heart attack, stroke, and cardiovascular death.
What the data show
Xylitol — commonly known as birch sugar — is widely used as a sweetener in sugar-free chewing gums, sweets, and a broad range of so-called sugar-free fitness and diet products. In the Canadian arm of the research, participants with elevated xylitol levels faced a 57 per cent higher risk of suffering a heart attack, stroke, or cardiovascular death over six years. A separate European long-term study spanning 30 years found the associated risk to be 18 per cent higher among those with elevated xylitol readings.
Study author Dr Marco Witkowski of the Charité Berlin noted that earlier work had already indicated xylitol could promote blood clot formation. "In earlier studies we were able to show that xylitol can promote the formation of blood clots," he said, suggesting the sweetener may influence the clotting process. Professor Christina Magnussen of the Universitätsklinikum Hamburg-Eppendorf elaborated on a plausible mechanism: "There are indications that xylitol makes platelets more active. This can make it easier for blood clots to form, which can trigger heart attacks or strokes." Such clots are frequently the direct cause of both conditions.
Crucial caveats: association, not causation
Both researchers were careful to distinguish between association and proof. The study is observational in design, meaning it cannot establish that xylitol directly causes cardiovascular disease. Professor Magnussen stated explicitly: "The researchers found a link between high xylitol levels in the blood and cardiovascular disease. But they cannot say with certainty whether xylitol is actually the cause." An alternative explanation is that people with certain metabolic disorders may coincidentally present with both elevated xylitol levels and a higher baseline cardiac risk — a confounding variable the study cannot rule out.
Dr Witkowski also acknowledged that xylitol remains classified as safe by regulatory authorities. Nevertheless, he argued the findings reveal a significant knowledge gap: "Our long-term data from the general population show how little we still know about the effects of xylitol on the heart and blood vessels. Further studies are urgently needed, especially as more and more food products contain xylitol."
Practical guidance
In the absence of definitive causal evidence, health professionals are not calling for xylitol to be avoided altogether, but are urging moderation. The German Nutrition Society recommends consuming no more than approximately 50 grams of free sugar per day — the equivalent of ten to twelve sugar cubes or half a litre of cola — and the same principle of restraint applies to sweetener alternatives. Neither sugar nor sugar substitutes, the research community broadly advises, should be consumed in large quantities.
The findings add to a growing body of evidence suggesting that the long-term cardiovascular effects of commonly used food additives remain poorly understood, underscoring the need for further large-scale, controlled research before definitive public health guidance can be issued.
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