Erythritol, a sugar substitute found in everything from low-carb ice creams to keto-friendly snacks and "sugar-free" sodas, has long been celebrated as a guilt-free sweetener. With nearly zero calories, 80% of sugar's sweetness, and minimal impact on blood sugar or insulin, it's a favourite for those managing obesity, diabetes, or low-carb diets. But a new study from the University of Colorado Boulder, published on June 16, 2025, in the Journal of Applied Physiology, suggests this popular sweetener may come with unexpected health risks, specifically, an increased likelihood of stroke.
The Study: Erythritol's Impact on Brain Cells
Led by Professor Christopher DeSouza and graduate student Auburn Berry, the study explored how erythritol affects human brain microvascular endothelial cells, which line blood vessels in the brain and play a critical role in vascular health. The researchers exposed these cells to erythritol at levels equivalent to a single sugar-free beverage for three hours. The results were concerning:
Reduced Nitric Oxide: This molecule helps relax and widen blood vessels. Lower levels can lead to vessel constriction, increasing cardiovascular strain.
Increased Endothelin-1: This protein constricts blood vessels, further raising the risk of impaired blood flow.
Blunted t-PA Production: Tissue plasminogen activator (t-PA) dissolves blood clots. Erythritol-treated cells produced less t-PA, suggesting a reduced ability to prevent clots, a key factor in strokes.
Elevated Free Radicals: The cells showed higher levels of reactive oxygen species (ROS), which can damage cells, promote inflammation, and accelerate aging.
These cellular changes align with an earlier epidemiological study of 4,000 people in the U.S. and Europe, which found that higher blood erythritol levels were linked to a greater risk of heart attack or stroke within three years. The Boulder study offers a possible explanation: erythritol may directly impair vascular function, setting the stage for cardiovascular events.
Why This Matters
Erythritol, approved by the FDA in 2001, is derived from fermented corn and is a staple in countless diet-friendly products. Its appeal lies in its low-calorie profile and minimal metabolic impact, making it a go-to for those on keto or low-carb diets. However, the study suggests that even a single serving could trigger harmful changes in brain blood vessels. For those consuming multiple erythritol-containing products daily, think a sugar-free soda, a keto protein bar, and low-carb dessert, the risks could be even higher.
Professor DeSouza cautions, "Our study adds to the evidence suggesting that non-nutritive sweeteners, generally purported to be safe, may not come without negative health consequences." This challenges the "healthy" label often attached to erythritol and similar sweeteners.
Limitations and Cautions
While the findings are alarming, the study has limitations. It was conducted in a lab on isolated cells, not in humans, so it doesn't directly prove that erythritol causes strokes. The three-hour exposure time also doesn't reflect long-term dietary habits, and the epidemiological data can't confirm whether high erythritol levels come from diet or the body's own production. Larger human studies are needed to solidify these findings.
Still, the results are a wake-up call. As Berry notes, "If your vessels are more constricted and your ability to break down blood clots is lowered, your risk of stroke goes up." This mechanistic insight makes the case for caution, especially for those with existing cardiovascular risks.
What Can You Do?
The researchers urge consumers to check product labels for erythritol or "sugar alcohols" and consider cutting back. This may be easier said than done, given erythritol's prevalence in processed foods. Here are some practical steps:
Read Labels: Look for erythritol or sugar alcohols in ingredient lists, especially in "sugar-free" or "low-carb" products.
Limit Intake: If you consume multiple erythritol-containing items daily, try reducing to one or two servings.
Choose Whole Foods: Opt for naturally low-sugar foods like fresh fruits or unsweetened teas to reduce reliance on processed products.
Stay Informed: Keep an eye on emerging research, as more studies may clarify erythritol's risks and benefits.
The Bigger Picture
This study adds to growing scepticism about non-nutritive sweeteners. While erythritol has been marketed as a safe, natural alternative to sugar, these findings suggest it's not risk-free. Other sweeteners, like aspartame and sucralose, have faced similar scrutiny, highlighting the need for ongoing research into food additives. The fact that erythritol's potential risks are only now emerging, over 20 years after its approval, underscores the importance of post-market surveillance.
For individuals managing diabetes or obesity, erythritol's benefits, low calories and minimal blood sugar impact, are significant. But these must be weighed against potential risks. Nutrition science is complex, and "healthy" alternatives aren't always as safe as they seem.
Final Thoughts
The University of Colorado Boulder study is a compelling reminder to approach dietary choices with caution. While erythritol may still have a place in moderation, its potential to harm brain blood vessels and increase stroke risk can't be ignored. Until larger studies confirm these findings, it's wise to monitor your intake, opting for whole foods, and stay updated on new research. In the world of nutrition, even the sweetest deals can come with a sour catch.
Reference: Berry, A. R., et al. (2025). The non-nutritive sweetener erythritol adversely affects brain microvascular endothelial cell function. Journal of Applied Physiology. DOI: 10.1152/japplphysiol.00276.2025
https://scitechdaily.com/scientists-warn-popular-sugar-substitute-linked-to-brain-cell-damage/
"New research indicates that erythritol, a sugar substitute commonly recommended for individuals with obesity or diabetes, may carry unexpected health risks.
From low-carb ice creams and keto-friendly protein snacks to "sugar-free" sodas, erythritol is a widely used sweetener found in countless diet and specialty food items.
However, new findings from the University of Colorado Boulder suggest that this commonly used sugar substitute may carry unexpected health risks. According to the research, erythritol can affect brain cells in ways that may increase the likelihood of stroke.
The study was published in the Journal of Applied Physiology
"Our study adds to the evidence suggesting that non-nutritive sweeteners that have generally been purported to be safe, may not come without negative health consequences," said senior author Christopher DeSouza, professor of integrative physiology and director of the Integrative Vascular Biology Lab.
Erythritol, a sugar alcohol that was first approved by the Food and Drug Administration in 2001, is typically made by fermenting corn. It is found in hundreds of products and is popular for several reasons. It contains nearly no calories, delivers about 80 percent of the sweetness of regular sugar, and has little effect on blood sugar or insulin levels. These traits make it especially appealing to people focused on weight loss, low-carb diets, or blood sugar management.
But recent research has begun to shed light on its risks.
Linking Erythritol to Cardiovascular Events
One recent study involving 4,000 people in the U.S. and Europe found that men and women with higher circulating levels of erythritol were significantly more likely to have a heart attack or stroke within the next three years.
DeSouza and first author Auburn Berry, a graduate student in his lab, set out to understand what might be driving that increased risk.
Researchers in the lab treated human cells that line blood vessels in the brain for three hours with about the same amount of erythritol contained in a typical sugar-free beverage.
They observed that the treated cells were altered in numerous ways: They expressed significantly less nitric oxide, a molecule that relaxes and widens blood vessels, and more endothelin-1, a protein that constricts blood vessels. Meanwhile, when challenged with a clot-forming compound called thrombin, cellular production of the natural clot-busting compound t-PA was "markedly blunted." The erythritol-treated cells also produced more reactive oxygen species (ROS), a.k.a. "free radicals," metabolic byproducts which can age and damage cells and inflame tissue.
Why Stroke Risk May Increase
"Big picture, if your vessels are more constricted and your ability to break down blood clots is lowered, your risk of stroke goes up," said Berry. "Our research demonstrates not only that, but how erythritol has the potential to increase stroke risk."
DeSouza notes that their study used only a serving-size worth of the sugar substitute. For those who consume multiple servings per day, the impact, presumably, could be worse.
The authors caution that their study was a laboratory study, conducted on cells, and larger studies in people are needed.
That said, De Souza encourages consumers to read labels, looking for erythritol or "sugar alcohol" on the label.
"Given the epidemiological study that inspired our work, and now our cellular findings, we believe it would be prudent for people to monitor their consumption of non-nutrient-sweeteners such as this one," he said."