The carbohydrate sweetener erythritol can pose a risk to cells in the brain

The popular zero-calorie sweetener, erythritol, can damage cells lined with blood vessels in the brain, new laboratory studies suggest.

This raises concerns about whether sweeteners increase the risk of stroke, but experts warn that more research is needed to know how these results actually affect human health.

“This study was conducted in a controlled environment of isolated cells, not entirely, rather than in the organism,” said Amy Reicherd, a nutritional neuroscientist at the University of Adelaide, Australia, who was not involved in the study. “The actual physiological impact on human health in the context of everyday diet remains uncertain,” Reicherd told Live Science via email.

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Erythritol is a sugar alcohol that is often found in sugar-free carbohydrate products. It also naturally occurs in fruits such as grapes, and although commercially available erythritol comes from fermented corn, it is produced by the body. It’s almost as sweet as sugar, but has no calories and has no effect on blood sugar levels, making it a long-term turn to people who manage their sugar intake.

However, some studies suggest that sweeteners may be risk-free. A 2023 study published in Nature Medicine, which includes more than 4,000 people in the US and Europe, linked high levels of erythritol in blood at high risk for blood clots, strokes and heart attacks. In the same year, the World Health Organization (WHO) advised against the long-term use of non-sugar sweeteners, citing evidence that it could increase the risk of certain conditions, including type 2 diabetes and cardiovascular disease.

However, due to 2023 research and data limitations, some have flagged scientists not fully understand potential health risks. A new study published in the Journal of Applied Physiology on June 16th has delved into this further.

Related: Non-sugar sweeteners can help you lose weight and may have health risks

The researchers grew human brain endothelial cells lined with blood vessels in the brain in the laboratory and exposed them to erythritol for three hours. They used as much of a 30 grams of sweetener as they do in a pint of sugar-free ice cream.

Three hours later, they observed signs of stress. Cells produced reactive molecules that produced more free radicals, damaged and senescent cells compared to cells that were not exposed to sweeteners. They also noticed a decline in nitric oxide, compounds that help dilate blood vessels, and elevated endothelin-1, which narrows blood vessels.

They also tested the cell’s response to thrombin, an enzyme involved in the formation of thrombus. Cells exposed to sweeteners released less proteins called tissue-type plasminogen activator (T-PA), which degrades thrombus than exposed cells. If this thrombolytic protein “severely blunted” in the body, it can interfere with blood flow and increase the chances of a stroke.

“In our experiment, senior research author Christopher Desousa, professor of integrated physiology at the University of Colorado Boulder University, told Live Science in an email, “In our experiment, we cultured human brain endothelial cells. “Our findings provide additional insight into how elevated levels of erythritol contribute to an increased risk of stroke and help uncover potential underlying mechanisms.”

However, Desouza warned that the study tested only one dose under laboratory conditions when cells were exposed directly to the substance for a long period of time. This may not reflect the actual use of the sweetener. “More research is needed to see if these effects can be tolerated with repeated or long-term exposures or other types of cells,” he said.

Reicherd agrees, adding that while laboratory research provides valuable insights, cautiousness is required to translate these findings into actual effects.

Nevertheless, Reichelt added that “observed cell changes raise effective concerns about long-term vascular health,” so those with existing cardiovascular problems may want to ease their intake. “Erythritol is generally considered safe by regulators, but some people and over-intakes can pose a risk,” she said.

Desouza highlighted the need for more research to determine the amount of erythritol that can be consumed without causing any harm.

“At this stage, we cannot define a specific safe limit,” emphasized Desouza. “However, if you regularly consume sugar-free or diet products, it’s wise to look at the amount of erythritol you’re consuming.”