Could xylitol be less heart-friendly than we thought?

Xylitol has long enjoyed a fairly wholesome reputation. The low-calorie sweetener turns up in everything from sugar-free chewing gum and sweets to yoghurt, jam and toothpaste, and is often marketed as an alternative to ordinary sugar.

But recent research has added to concerns that its effects on the cardiovascular system may be more complicated than previously thought.

According to The Guardian, researchers studying more than 17,700 people found that those with the highest levels of xylitol in their blood were more likely to suffer a heart attack, stroke or death than those with the lowest levels.

Over six years, people in the highest quarter were 57% more likely to experience one of these major cardiovascular events. Even after 30 years, their risk remained 18% higher.

The findings were recently presented at the European Society of Cardiology congress in Munich.

What is xylitol?

Xylitol is a sugar alcohol that occurs naturally in small amounts in some fruits and vegetables. In manufactured form, it is added to foods and other products in much larger quantities to provide sweetness with fewer calories than sugar.

It has also become popular in sugar-free and low-carbohydrate products.

The latest study found that the higher the xylitol level in the blood, the higher the rate of cardiovascular events tended to be, even after researchers accounted for factors such as age, sex, body mass index, high blood pressure, diabetes and cholesterol levels.

Notably, the pattern does not prove xylitol caused the events, even if it raises questions worth investigating.

The new findings build on a 2024 study led by Cleveland Clinic researchers, which found that people with higher circulating xylitol levels had a greater risk of heart attack, stroke or death over three years.

Laboratory and animal experiments also suggested xylitol could make platelets more reactive and promote clot formation.

In a small experiment involving healthy volunteers, consuming a xylitol-sweetened drink increased several measures of platelet activity compared with glucose. That matters because overly reactive platelets can contribute to blood clots that block arteries, potentially triggering a heart attack or stroke.

Still, researchers are careful not to overstate the finding: observational studies can identify patterns, but they cannot establish that one factor directly caused another.

Blood xylitol levels may also be influenced by the body’s own metabolism, not just by how much xylitol a person consumes.

So, should you avoid it?

The research does not mean everyone needs to throw out every packet of sugar-free gum or tube of toothpaste containing xylitol.

Indeed, researchers have specifically cautioned that oral-care products are not the main concern; the bigger question is repeated consumption of foods or drinks containing relatively large amounts of the sweetener.

It is also not a reason to switch back to large amounts of sugar. Experts quoted by The Guardian stressed that excess sugar remains a health concern in its own right, and the broader lesson is to be cautious about assuming that a “sugar-free” label automatically makes a product healthier.

For now, the most sensible approach is the least dramatic one: limit highly processed foods, pay attention to what is in them, and aim for an overall balanced diet rather than relying heavily on any one sugar substitute.

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