One Common Sweetener May Increase Stroke Risk by Damaging The Brain's Protective Barrier - ScienceAlert

Add ScienceAlert on Google (Myriams-Fotos/Pixabay) The blood-brain barrier surrounds the blood vessels that run through the brain, letting in oxygen and nutrients while keeping out toxins and pathogens. It's an absolutely essential line of defense that protects the brain from damage. Researchers now believe they have discovered a significant threat to this barrier and its stability – and from something we're willingly putting into our bodies. Erythritol has been used as an artificial sweetener for decades. It's a favorite with consumers and food producers because it has almost zero calories, is 60–80 percent as sweet as table sugar, and doesn't impact insulin levels. However, in a study published in the Journal of Applied Physiology, a team from the University of Colorado, Boulder found that it had damaging effects on blood-brain barrier cells (brain endothelial cells) grown in the lab. Past studies have suggested a link between higher erythritol levels and a greater risk of heart attack or stroke, and this additional research could explain why, if the same effects occur in the body. "The results presented herein support and experimentally extend epidemiological studies reporting a link between erythritol and increased stroke risk," write the researchers in their published paper. "Additional clinical studies are warranted on the potential long-term health effects of erythritol consumption." The experiments led by the researchers found that adding erythritol to endothelial cells caused them to produce less nitric oxide, which makes blood vessels wider and more relaxed. It also created more endothelin-1, a protein that constricts blood vessels – so a double strike for keeping blood vessels clear. The cells' stimulated release of an important clot-busting compound called tissue plasminogen activator (t-PA) was reduced, and the number of byproducts called free radicals – reactive oxygen species molecules that can damage tissues – increased. These are all worrying effects, and may explain why more erythritol in the blood has been linked to an increased risk of clots forming and causing strokes. The chemical is restricting the normal function of endothelial cells, leaving the brain exposed. "Big picture, if your vessels are more constricted and your ability to break down blood clots is lowered, your risk of stroke goes up," says physiologist Auburn Berry. "Our research demonstrates not only that, but how erythritol has the potential to increase stroke risk." The researchers only tested brain endothelial cells here, linking their findings to ischemic strokes (where a clot blocks blood flow to the brain). It's possible that erythritol is affecting endothelial cells around blood vessels in other parts of the body, potentially contributing to heart attack risk, but that wasn't the focus here. Also of concern is how the damage done to endothelial cells could leave the brain exposed to further harm — but again that's not something this study covered. The findings detailed here are worrying enough for the researchers to suggest that erythritol consumption should be cut down. "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," says physiologist Christopher DeSouza. The biggest caveat to emphasize here is that this is a lab cell test, not a study of living people. The mechanics and dosage of erythritol don't necessarily match up with real-world scenarios. It's also worth pointing out that the human body naturally produces erythritol. It may be that higher levels of it aren't directly due to food and drink consumption, but a sign of something else going wrong. In addition, some research has found erythritol can boost vascular health, not harm it. All of these considerations need to be carefully weighed up – but the potentially negative impacts of erythritol certainly need to be investigated further, especially as its classification as a sugar alcohol has excluded it from other warnings around artificial sweeteners. Related: A Single Molecule May Explain How Blood Flow in The Brain Triggers Dementia "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," says DeSouza. The research has been published in the Journal of Applied Physiology. This article was fact-checked and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.