A popular sweetener could be damaging your brain’s defences, says recent study

Found in everything from protein bars to energy drinks, erythritol has long been considered a safe alternative to sugar. But new research suggests this widely used sweetener may be quietly undermining one of the body’s most crucial protective barriers – with potentially serious consequences for heart health and stroke risk.

A recent study from the University of Colorado suggests erythritol may damage cells in the blood-brain barrier, the brain’s security system that keeps out harmful substances while letting in nutrients. The findings add troubling new detail to previous observational studies that have linked erythritol consumption to increased rates of heart attack and stroke.

In the new study, researchers exposed blood-brain barrier cells to levels of erythritol typically found after drinking a soft drink sweetened with the compound. They saw a chain reaction of cell damage that could make the brain more vulnerable to blood clots – a leading cause of stroke.

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Erythritol triggered what scientists call oxidative stress, flooding cells with harmful, highly reactive molecules known as free radicals, while simultaneously reducing the body’s natural antioxidant defences. This double assault damaged the cells’ ability to function properly, and in some cases killed them outright.

But perhaps more concerning was erythritol’s effect on the blood vessels’ ability to regulate blood flow. Healthy blood vessels act like traffic controllers, widening when organs need more blood – during exercise, for instance – and tightening when less is required. They achieve this delicate balance through two key molecules: nitric oxide, which relaxes blood vessels, and endothelin-1, which constricts them.

The study found that erythritol disrupted this critical system, reducing nitric oxide production while ramping up endothelin-1. The result would be blood vessels that remain dangerously constricted, potentially starving the brain of oxygen and nutrients. This imbalance is a known warning sign of ischaemic stroke – the type caused by blood clots blocking vessels in the brain.

Even more alarming, erythritol appeared to sabotage the body’s natural defence against blood clots. Normally, when clots form in blood vessels, cells release a “clot buster” called tissue plasminogen activator that dissolves the blockage before it can cause a stroke. But the sweetener blocked this protective mechanism, potentially leaving clots free to wreak havoc.

The laboratory findings align with troubling evidence from human studies. Several large-scale observational studies have found that people who regularly consume erythritol face significantly higher risks of cardiovascular disease, including heart attacks and strokes. One major study tracking thousands of participants found that those with the highest blood levels of erythritol were roughly twice as likely to experience a major cardiac event.

However, the research does have limitations. The experiments were conducted on isolated cells in laboratory dishes rather than complete blood vessels, which means the cells may not behave exactly as they would in the human body. Scientists acknowledge that more sophisticated testing – using advanced “blood vessel on a chip” systems that better mimic real physiology – will be needed to confirm these effects.

The findings are particularly significant because erythritol occupies a unique position in the sweetener landscape. Unlike artificial sweeteners such as aspartame or sucralose, erythritol is technically a sugar alcohol – a naturally occurring compound that the body produces in small amounts. This classification helped it avoid inclusion in recent World Health Organization guidelines that discouraged the use of artificial sweeteners for weight control.

Erythritol has also gained popularity among food manufacturers because it behaves more like sugar than other alternatives. While sucralose is 320 times sweeter than sugar, erythritol provides only about 80% of sugar’s sweetness, making it easier to use in recipes without creating an overpowering taste. It’s now found in thousands of products, especially in many “sugar-free” and “keto-friendly” foods.

Trade-off

Regulatory agencies, including the European Food Standards Agency and the US Food and Drug Administration, have approved erythritol as safe for consumption. But the new research adds to a growing body of evidence suggesting that even “natural” sugar alternatives may carry unexpected health risks.

For consumers, the findings raise difficult questions about the trade-offs involved in sugar substitution. Sweeteners like erythritol can be valuable tools for weight management and diabetes prevention, helping people reduce calories and control blood sugar spikes. But if regular consumption potentially weakens the brain’s protective barriers and increases cardiovascular risk, the benefits may come at a significant cost.

The research underscores a broader challenge in nutritional science: understanding the long-term effects of relatively new food additives that have become ubiquitous in the modern diet. While erythritol may help people avoid the immediate harms of excess sugar consumption, its effect on the blood-brain barrier suggests that frequent use could be quietly compromising brain protection over time.

As scientists continue to investigate these concerning links, consumers may want to reconsider their relationship with this seemingly innocent sweetener – and perhaps question whether any sugar substitute additive is truly without risk.

Havovi Chichger does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.