Erythritol may damage the blood-brain barrier and raise stroke risk

Erythritol, which appears in products ranging from protein bars to energy drinks, has long been viewed as a safe replacement for sugar.

However, research indicates that this commonly used sweetener could quietly impair one of the body’s most important protective barriers, potentially affecting heart health and the risk of stroke.

A University of Colorado study indicates that erythritol could harm cells within the blood-brain barrier, the brain’s protective system that blocks damaging substances while allowing nutrients to enter.

These results provide worrying additional detail to earlier observational research associating erythritol intake with higher incidences of heart attack and stroke.

Erythritol and blood-brain barrier damage

For the latest study, scientists treated blood-brain barrier cells with erythritol concentrations commonly reached after consuming a soft drink sweetened with the compound. They observed a sequence of cellular damage that could leave the brain more susceptible to blood clots, one of the principal causes of stroke.

Erythritol caused oxidative stress, as scientists describe it, filling cells with damaging and highly reactive molecules called free radicals while also lowering the body’s own antioxidant defences. This two-pronged effect impaired the cells’ normal function and, in certain cases, killed them completely.

More worryingly, perhaps, erythritol affected how blood vessels control blood flow. In healthy vessels, this works rather like traffic management: they expand when organs require increased blood supply, such as during exercise, and narrow when demand falls.

This finely tuned process depends on two important molecules: nitric oxide, which causes blood vessels to relax, and endothelin-1, which makes them contract.

Effects on blood flow and clots

The research showed that erythritol interfered with this essential system, lowering nitric oxide production and increasing endothelin-1. Consequently, blood vessels could remain excessively constricted, potentially depriving the brain of oxygen and nutrients.

Such an imbalance is an established warning sign for ischaemic stroke, the form of stroke in which blood clots obstruct blood vessels in the brain.

Erythritol also seemed to undermine the body’s own protection against blood clots, which is even more concerning. Ordinarily, when clots develop in blood vessels, cells release a “clot buster” known as tissue plasminogen activator, which breaks down the obstruction before it can trigger a stroke.

Yet the sweetener prevented this safeguarding process, potentially allowing clots to cause damage unchecked.

The laboratory results are consistent with concerning evidence from studies in people. Several large observational studies have reported that regular erythritol consumers have substantially greater risks of cardiovascular disease, including heart attacks and strokes.

One significant study that followed thousands of people found that participants with the greatest erythritol levels in their blood were approximately twice as likely to have a major cardiac event.

There are limitations to this research, however. The tests used individual cells in laboratory dishes rather than whole blood vessels, so the cells might not respond precisely as they do in the human body. Researchers recognise that more advanced experiments, using “blood vessel on a chip” systems that more accurately reproduce real physiology, will be necessary to verify these effects.

Erythritol’s place among sweeteners makes these findings particularly notable. Rather than being an artificial sweetener like aspartame or sucralose, erythritol is technically a sugar alcohol: a naturally occurring compound produced by the body in small quantities.

That categorisation meant it was not included in recent World Health Organization guidance advising against artificial sweeteners for weight control.

Food manufacturers have also increasingly adopted erythritol because it behaves more similarly to sugar than many other alternatives.

Sucralose is 320 times sweeter than sugar, whereas erythritol delivers around 80% of sugar’s sweetness. This makes it simpler to include in recipes without producing an overwhelmingly sweet flavour. It is now present in thousands of products, particularly “sugar-free” and “keto-friendly” foods.

Trade-off

Regulators, including the European Food Standards Agency and the US Food and Drug Administration, have approved erythritol as safe to consume. Nonetheless, this new research contributes to growing evidence that even “natural” alternatives to sugar can bring unforeseen health risks.

For consumers, the findings prompt challenging questions about the compromises involved in replacing sugar. Sweeteners such as erythritol may assist with weight management and diabetes prevention by enabling people to cut calories and manage spikes in blood sugar.

However, if consuming it regularly may weaken the brain’s protective barriers and raise cardiovascular risk, those advantages could carry a considerable price.

The research highlights a wider difficulty for nutritional science: determining the long-term consequences of comparatively recent food additives that are now widespread in modern diets.

Although erythritol might help people avoid the immediate harm linked to consuming too much sugar, its impact on the blood-brain barrier indicates that frequent use may gradually erode the brain’s protection.

While scientists continue examining these troubling associations, consumers may wish to rethink their use of this apparently harmless sweetener, and perhaps consider whether any added sugar substitute is genuinely risk-free.

Havovi Chichger, Professor, Biomedical Science, Anglia Ruskin University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.

An earlier version of this article was published in July 2025.