Erythritol and the Blood-Brain Barrier: What the New Research Means for Your Sweetener Choices

Your morning protein bar promises to keep you fueled without the sugar crash. That sugar-free soda does the same. The common ingredient making it all possible is erythritol, a sugar alcohol that has become a staple of the low-carb and keto food movement. But new research is raising questions about whether this popular sweetener deserves its clean reputation.

A study published in 2025 by researchers at the University of Colorado Boulder found that erythritol may damage the cells that line the blood-brain barrier, the specialized structure that protects the brain from potentially harmful substances circulating in the bloodstream [1]. The findings add to a growing body of evidence linking erythritol consumption to cardiovascular risks, and they come just two years after a major Cleveland Clinic study drew similar concerns about the sweetener's effects on heart health [2].

What the Brain Study Found

The CU Boulder research, published in the Journal of Applied Physiology, focused on brain endothelial cells, the specialized cells that form the internal lining of blood vessels in the brain. These cells are critical components of the blood-brain barrier, controlling what substances can pass from the blood into brain tissue.

Lead researcher Christopher DeSouza and his team found that exposure to erythritol impaired the function of these cells in several ways [1]. The sweetener reduced production of nitric oxide, a signaling molecule that helps blood vessels relax and maintain healthy blood flow. Simultaneously, erythritol increased production of endothelin-1, a compound that promotes blood vessel constriction. The researchers also observed reduced activity of tissue plasminogen activator (t-PA), an enzyme that helps break down blood clots. Perhaps most concerning, erythritol exposure increased reactive oxygen species (ROS) in the cells, indicating elevated oxidative stress, a condition linked to cellular damage and accelerated aging.

The study raises the possibility that regular erythritol consumption could compromise the integrity of the blood-brain barrier over time, potentially increasing susceptibility to stroke and other neurological damage.

The Cardiovascular Evidence Builds

The CU Boulder findings resonate with earlier research from the Cleveland Clinic that drew significant attention when it was published in Nature Medicine in 2023 [2]. That large-scale study tracked patients over three years and found that those with the highest blood levels of erythritol were approximately twice as likely to experience a heart attack or stroke compared to those with lower levels. The researchers identified erythritol as an independent risk factor for major cardiovascular events.

A follow-up study from the Cleveland Clinic in 2024 provided even more direct evidence of harm [3]. In a controlled experiment with 20 healthy volunteers, researchers gave participants a drink containing roughly 30 grams of erythritol, a typical amount found in a commercial sugar-free soda or muffin. Within minutes, blood erythritol levels in the participants increased by approximately 1,000-fold. The researchers then measured platelet function and found that the volunteers' platelets became significantly more prone to clotting. Platelets that are more reactive are more likely to form dangerous blood clots that can block arteries and cause heart attacks or strokes.

How Erythritol Became Ubiquitous

Erythritol has been part of the food supply since the FDA granted it generally recognized as safe (GRAS) status in 2001 [4]. The sweetener provides about 80 percent of the sweetness of sugar but contributes almost no calories, making it attractive for weight management and blood sugar control. It does not raise blood glucose levels, which makes it popular among people with diabetes and those following low-carbohydrate eating patterns.

The compound occurs naturally in some fruits and fermented foods, but most erythritol used in processed products is manufactured through fermentation of glucose. Food manufacturers quickly adopted it for use in protein bars, keto-friendly snacks, sugar-free beverages, and low-calorie desserts. For consumers seeking to reduce sugar and calorie intake, products containing erythritol seemed like a safe choice backed by regulatory approval.

The GRAS designation means the FDA considered the available evidence sufficient to conclude that erythritol was safe for its intended uses. However, GRAS status does not require the same level of scrutiny as the full FDA approval process for food additives, and new scientific findings can change the risk assessment over time.

The Broader Sweetener Picture

Erythritol is not the only sugar alcohol drawing scrutiny from researchers. The Cleveland Clinic published additional research in June 2024 highlighting similar concerns about xylitol, another widely used sugar substitute found in sugar-free gums, mints, and baked goods [5]. Like erythritol, xylitol was associated with increased platelet reactivity and elevated cardiovascular risk in the clinical studies.

The emerging research on both sweeteners suggests that the assumption of safety based on GRAS approval may need reexamination in light of newer human study data. Both compounds appear to affect platelet function in ways that could increase thrombosis risk, and the brain endothelial cell findings for erythritol suggest potential harm to the protective barrier around the brain.

What This Means for Your Choices

This article summarizes published research on erythritol and is not intended as medical advice. Before making any dietary changes, particularly if you have existing health conditions, consult a qualified healthcare provider.

The research is still evolving, and no single study provides definitive proof that erythritol is dangerous for everyone. The cardiovascular associations observed in the patient studies do not prove causation, and the laboratory findings on brain cells require further confirmation in human trials. However, the consistency of findings across different research teams and methodologies is notable and warrants attention.

For individuals with existing cardiovascular risk factors, a history of heart disease, or concerns about clotting disorders, the emerging evidence may tip the scales toward caution. The human feeding study showing a 1,000-fold increase in blood erythritol levels after a single drink suggests that typical dietary consumption can produce concentrations that affect platelet behavior in ways the researchers characterized as clinically meaningful.

For the general population, the findings argue for moderation and thoughtful evaluation of how often sugar-free products are consumed. Reading ingredient lists and being aware of how frequently erythritol appears in your diet can help you make informed choices while the scientific community continues to investigate these concerns.

Looking Ahead

Researchers are calling for larger, longer-term human studies to clarify the relationship between erythritol consumption and cardiovascular outcomes. The current evidence, while concerning, is not yet sufficient to definitively recommend avoiding erythritol entirely. However, the biological mechanisms identified in recent studies provide plausible pathways through which regular erythritol consumption could increase risk for heart attack and stroke.

The sweetener industry continues to maintain that erythritol is safe based on its long history of use and existing regulatory approvals. The broader scientific community is not dismissing the new research but is advocating for more comprehensive investigation before drawing firm conclusions.

For now, consumers are left to weigh the available evidence against their individual health circumstances and dietary preferences. The days of assuming that zero-calorie sweeteners are automatically better choices than sugar may be numbered.