Sweetener xylitol linked to higher risk of heart attacks and strokes

A sweetener called xylitol that is commonly used in sugar-free drinks, chewing gum and toothpaste has been linked to a higher risk of heart attacks and strokes.

Often marketed as “low-carb”, “natural” and “keto-friendly”, xylitol is a sugar alcohol that is found in fruits and vegetables, but at about 1000 times lower levels than those added to commercial products. It can also be artificially prepared via chemical reactions from plant materials.

Last year, Stanley Hazen at the Cleveland Clinic in Ohio and his colleagues found that the sweetener erythritol was associated with an increased cardiovascular risk. Wondering if xylitol may also affect heart health, Hazen led a investigation of 3306 adults in the US and Europe.

The researchers analysed a one-off blood sample from the participants to check their xylitol levels after they fasted overnight. Over a three-year follow-up period, the team found that a third of those who had the highest levels of circulating xylitol were more likely to experience a cardiovascular event, such as a heart attack or stroke.

To better understand this trend, the researchers examined the effects of xylitol on human blood cells called platelets in the laboratory and on platelet activity in mice. Platelets cluster together at the site of an injury to prevent bleeding, but they can also clot inside blood vessels. This can affect blood supply to the heart and brain, raising the risk of cardiovascular events.

The researchers found that the human platelets showed signs of being more prone to clotting when incubated with xylitol, compared with a saline incubation. The mice also had significantly faster clot formation in their veins after receiving xylitol injections.

Finally, the team tracked platelet activity in 10 people after giving them water that had been sweetened with the same amount of xylitol. Within 30 minutes, they showed a 1000-fold jump in levels of xylitol in their blood plasma and every measure supporting the readiness of platelet clotting increased, especially for those who had the highest levels of xylitol in their blood.

“This study again shows the immediate need for investigating sugar alcohols and artificial sweeteners,” says Hazen. “It does not mean throw out your toothpaste if it has xylitol in it, but we should be aware that consumption of a product containing high levels could increase the risk of blood clot-related events.”

Combined with the previous findings on erythritol, the findings “highlight the need for systematic studies into the effects of artificial sweeteners on cardiovascular risks”, says Silvia Radenkovic at University Medical Center Utrecht in the Netherlands.