A common sugar substitute found in protein bars and diet drinks may not be as harmless as once believed. New laboratory research suggests erythritol could interfere with the blood-brain barrier, a protective layer that shields the brain from harmful substances while allowing nutrients to pass through. Disruption of this barrier may increase vulnerability to stroke.
In the study, researchers exposed human blood-brain barrier cells to levels of erythritol similar to those seen after consuming a sweetened beverage. The cells showed signs of oxidative stress and reduced antioxidant defenses. The sweetener also altered molecules that regulate blood vessel widening and narrowing, changes that could limit blood flow and raise the risk of clot-related stroke.
The findings build on earlier observational research linking higher blood levels of erythritol to increased rates of heart attack and stroke. However, the experiments were conducted in isolated cells rather than in people, and more advanced studies are needed to confirm real-world effects. Health agencies currently consider erythritol safe, but the new data add to ongoing debate about the long-term impact of sugar substitutes on cardiovascular health.
SOURCE:
Science Alert, February 10, 2026