Xylitol, erythritol: Artificial sweeteners carry real health risks

It's just as sweet as table sugar but has 40% fewer calories, and studies show it may help prevent tooth decay. This is why many people value the artificial sweetener xylitol, also known as birch sugar.

Chemically classified as a sugar alcohol, it can be used to sweeten baked goods, coffee and tea, and is found in sweets, chewing gum, fizzy drinks and oral care products. The same goes for erythritol, another sugar alcohol used as an artificial sweetener, and which has hardly any calories at all.

But although they're promoted as healthy sugar alternatives, health and nutrition experts are warning they should be consumed only in moderation. Here are three reasons:

Reason 1: Risk of flatulence and diarrhoea

Consumed in large amounts, sugar alcohols can cause gastrointestinal problems such as flatulence and diarrhoea. "This is why products with a proportion of sugar alcohols greater than 10% are required to display the warning that excessive consumption may induce laxative effects," says Silke Restemeyer, spokeswoman of the German Nutrition Society (DGE).

There's no general risk threshold for these symptoms since individual tolerance to sugar alcohols varies.

Reason 2: Lack of scientific findings

Germany's Federal Institute for Risk Assessment (BfR), whose remit is the protection of human health, said in a statement last year that study findings on sugar alcohols' adverse health effects remained spotty.

However, a recent study by Cleveland Clinic in the US state of Ohio, published in the European Heart Journal, found xylitol consumption to be associated with a higher risk of thrombosis and "major adverse cardiovascular events" such as a heart attack and stroke.

The research team analysed blood samples from more than 3,300 cardiovascular patients and observed the patients over a three-year period.

In a 2023 study, Dr Marco Witkowski, lead author of the Cleveland Clinic study and a cardiologist at the German Heart Centre of Charité university hospital in Berlin, found erythritol to be associated with similar risks. Researchers say further studies of the cardiovascular safety of these sugar alcohols are warranted.

Reason 3: Habituation hard to break

Be it sugar or artificial sweeteners, high intake leads to habituation that can be very difficult to break. This, says Restemeyer, is why they should be consumed only in moderation - especially by children.

"Diet" or "light" beverages, in particular, can increase habituation to sweet flavours. While generally sugar-free and with few or no calories, "they contain food additives such as artificial sweeteners, and often artificial colouring and flavourings as well, making them less recommendable," she remarks.

So if you want to live healthier, it's important to accustom yourself to foods and drinks that are less sweet. Take heart - your appetite for sweetness will gradually diminish.