For many years, non-sugar sweeteners – whether made artificially or from natural sources – have been considered beneficial to health.
With zero or minimal calories, substituting them for added sugars has been thought to help people control weight and, in so doing, prevent weight-related health problems.
Over recent years, however, potential health risks of non-sugar sweeteners have been surfacing.
In 2023, the World Health Organization warned against using non-sugar sweeteners for weight loss or preventing unhealthy weight gain. According to WHO, the evidence wasn’t strong that doing so offered such benefits.
What’s more, there was data to suggest that long-term use of non-sugar sweeteners may increase the risk of type 2 diabetes and cardiovascular disease.
Now, a low-calorie sweetener called xylitol is being called out for its potential to harm cardiovascular health. Here’s what to know.
What is xylitol?
Xylitol is a sugar alcohol, or polyol, a type of carbohydrate that occurs naturally in low amounts in certain fruits and vegetables. The body also produces it in small quantities.
For use as a sweetener, xylitol is produced commercially from corn cob or birch bark. It can be used to sweeten “low-sugar” candies, baked goods, frozen desserts, fruit spreads and condiments such as ketchup and barbecue sauce.
In smaller amounts, xylitol may be added to sugar-free chewing gums, chewable vitamin supplements, breath mints, throat lozenges and cough syrups.
Xylitol is also sold in bulk as a sweetener for cooking and baking.
The sweetness of xylitol is comparable to table sugar but because sugar alcohols are only partly absorbed by the body, it provides fewer calories, 2.4 calories per gram versus four.
Other sugar alcohols permitted in Canada for use as food additives include erythritol, mannitol, sorbitol, maltitol, lactitol and isomalt.
The latest findings
The research, conducted at Cleveland Clinic and published June 6 in the European Heart Journal, involved a series of studies.
First, the researchers examined saved fasting plasma samples from 3,306 participants who had taken part in one of two earlier clinical trials in the U.S. and Europe. All were undergoing elective cardiac tests.
They found that those with the highest plasma xylitol levels had a significantly greater risk of heart attack, stroke or death over three years compared to those who had the lowest levels, regardless of gender.
Next, the researchers found that xylitol accelerated platelet activity when they added it to human blood in a test tube and when they fed it to mice.
Platelets are small cells in our bloodstream that form sticky clots to stop bleeding when blood vessels are damaged. Blood clots can also cause heart attack and stroke.
Finally, the researchers had 10 healthy volunteers drink water sweetened with 30 grams of xylitol, an amount found in two cups of xylitol-sweetened ice cream, a xylitol-sweetened baked good or several pieces of xylitol-sweetened candy.
Within 30 minutes, plasma xylitol levels increased 1000-fold and the researchers observed a marked increase in platelet activity in all volunteers.
In 2023, the researchers found similar results for the sugar alcohol erythritol, which is more prevalent than xylitol in low-sugar products. Erythritol is also mixed with stevia and monk fruit tabletop sweeteners.
Limitations
While these findings are compelling, there are limitations to consider.
The findings from the 3,306 clinical trial participants showed only an association between high xylitol plasma levels and increased risk of heart attack, stroke and death. This does not prove that xylitol was a direct cause.
As well, since dietary information was not collected from these participants, it is possible that other diet components contributed to the increased risk.
The results also don’t prove that increased platelet activity was responsible for these cardiovascular events.
The researchers acknowledged that further study is needed to assess the long-term safety of xylitol and other sugar alcohols.
In the meantime…
These new findings add to an accumulating body of research suggesting that artificial sweeteners are not harmless substances. They should serve as a warning bell.
To limit your intake of xylitol and other sugar alcohols, read labels. If these sweeteners are added to a food product, the grams of sugar alcohols or polyols must be declared on the nutrition label.
The names of individual sugar alcohols must also be stated on the ingredient list.
If artificial sweeteners are very much a part of your regular diet, make a plan to gradually cut back. That goes for added sugars too.
What to do instead
Replace artificially- and sugar-sweetened drinks with water or unsweetened flavoured carbonated water.
Incrementally reduce the amount of sweetener you add to coffee, tea, hot cereal and other foods.
Use whole fruit to sweeten meals. Add berries to unsweetened yogurt or stir chopped dates into oatmeal. Serve fruit for dessert.
Reducing your intake of ultra-processed foods, many of which are high in sweeteners, is another smart way to reduce your intake of sugar and sugar substitutes.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD