There’s nothing sweet about this. 

Recent research indicates that a widely used sugar substitute, commonly found in items such as protein bars and low-calorie ice creams, might negatively impact the blood vessels in the brain.

This adds to the mounting evidence connecting this prevalent ingredient to an elevated risk of stroke and other significant cardiovascular issues.

Erythritol is classified as a sugar alcohol, a type of carbohydrate. It occurs naturally in minimal amounts in fruits and vegetables, and our bodies also generate it in small quantities during regular metabolic processes, as per the Mayo Clinic.

But the version added to foods is commercially manufactured by fermenting corn — and it shows up in tons of “keto,” “diabetes-friendly” and “zero sugar” products.

With only 6% of the calories of regular sugar and about 70% of the sweetness, erythritol is marketed as a smart choice for weight control. It also doesn’t raise blood sugar or insulin levels, and even helps fight tooth decay by targeting cavity-causing bacteria.

“We decided to study erythritol because it is widely marketed and consumed as a ‘safe’ sugar alternative,” Auburn Berry, lead study author and a graduate student at the University of Colorado Boulder, told Women’s Health.

“However, emerging evidence has linked erythritol intake to an increased risk of cardiovascular and cerebrovascular events, particularly ischemic stroke,” she added — noting that how exactly it causes harm hasn’t been fully understood until now.

To get a clearer picture, researchers exposed human brain blood vessel cells to an erythritol solution containing about 30 grams — roughly the amount in one can of artificially sweetened soda.

Within just three hours, they saw troubling effects: oxidative stress spiked by 75%, which can harm both the cells and nearby tissue.

The cells also produced 20% less nitric oxide, a key compound that helps blood vessels relax. Erythritol also triggered more vessel-constricting compounds and reduced a protein that helps break up clots.

Researchers concluded the sweetener “potentially contributes to [an] increased risk of ischemic stroke,” in which blood flow to the brain is blocked.

The CDC estimates that nearly 9 out of 10 strokes are of this type. Ischemic strokes can cause permanent brain damage or death, and are a leading cause of long-term disability in the US.

“This study offers valuable insights into the potential risks of erythritol on brain blood vessel health, especially for people seeking to improve or protect their vascular and cognitive function,” Dr. Thomas M. Holland, a physician-scientist who wasn’t involved in the study, told Medical News Today.

“The findings challenge the perception of erythritol as a harmless sugar substitute and underscore the need for moderation, particularly in those with risk factors for vascular disease,” he added.

The study was conducted in a lab, not in humans, so more research is needed to understand exactly how it plays out in real life. Still, the findings echo prior research that has raised serious concerns.

In 2023, researchers at the Cleveland Clinic studied more than 4,000 adults and found those with the highest erythritol levels in their blood were more likely to suffer heart attacks or strokes within the next three years.

And in 2024, the same group of scientists found that erythritol consumption made participants’ platelets stickier, potentially increasing the risk of blood clots. 

“It’s very troubling,” said Dr. Stanley Hazan, a specialist in preventive cardiovascular medicine and lead author of the 2023 and 2024 studies.

“We know that people buying these products are trying to do something good for their health by eating foods that are promoted as better for them. But in reality, they may be inadvertently increasing their risk for harm,” he told the Cleveland Clinic.

The FDA considers erythritol safe, largely because it occurs naturally in small amounts. But as a food additive, it’s used at concentrations up to 1,000 times higher than what’s found in fruits or our bodies.

“Naturally occurring erythritol isn’t the problem,” Hazan explained. “It’s the high doses of erythritol from packaged foods that we’re seeing have very adverse effects.”

To make things murkier, erythritol isn’t always easy to spot. It falls under the broader “sugar alcohols” category on nutrition labels, which aren’t required to name specific ingredients.

Still, there are clues: erythritol often hides in products labeled as “keto-safe,” “diabetes-safe,” “no sugar,” “low sugar,” “naturally sweetened” or “zero-calorie.”

It’s also a key ingredient in popular sugar substitutes like Truvia and Splenda Naturals Stevia — and often turns up in sugar-free ice cream, gum, candy, baked goods, protein bars and even fruit spreads.