The sugar substitute xylitol is linked to an increased risk of heart attack and stroke

The researchers noted that while xylitol is not as commonly used in ketogenic or sugar-free foods in the U.S., it is widely used in other countries. “We were trying to discover the next cholesterol, another pathway that contributes to heart disease that occurs naturally in our bodies,” said Hazen, who is also chief of the Division of Cardiovascular and Metabolic Sciences at the Cleveland Clinic’s Lerner Research Institute. “And we think we know this: erythritol or xylitol, these sugar alcohols, are linked to the development of heart disease or at least the development of future heart problems.”

The same research team found a similar link between erythritol and cardiovascular risk last year.

The use of sugar substitutes is increasing

The results are as follows The use of sugar alcohols like xylitol is increasing as keto and low-carb diet trends lead to growth in alternative sweeteners touted as “natural.” In 2021, $1.19 billion worth of xylitol products were sold, and that market is expected to grow to about $1.48 billion by 2030, according to research firm Custom Market Insights.

“Over the last decade or two, there has been this unusual situation where people have been confronted with levels of xylitol that have never been seen before in our evolution,” Hazen said.

The findings challenge the common perception that sugar alcohols like xylitol and erythritol are healthy, natural sugar alternatives. People think of them as natural because our bodies produce them as part of our energy metabolism; however, our cells produce them in much smaller amounts. These sugar alcohols are manufactured industrially, with bacteria or yeast undergoing brewing and fermentation processes to create a chemical that tricks our taste buds, Hazen said.

“Even though it’s a natural compound, it’s being used in a very unnatural way, at a level that’s massively, massively higher than could ever occur in our bodies under normal conditions,” Hazen said.

Researchers also found that elevated xylitol levels may be worse for the heart than cholesterol. A high-cholesterol diet can increase our blood cholesterol levels by 10 to 30 percent, Hazen said.

The researchers found that consuming a product high in xylitol increased the chemical’s levels in the blood by 1,000 times — or 100,000 percent — and remained elevated for four to six hours.

Put another way, among the thousands of people Hazen treats in his preventive cardiology clinic, those whose cholesterol levels are in the top quartile have a 30 percent higher risk of cardiovascular disease than those whose cholesterol levels are in the bottom quartile. But those whose blood xylitol levels are in the top quartile have a 200 percent higher risk of cardiovascular disease than those whose blood xylitol levels are in the bottom quartile.

“This study adds to a growing body of literature on the potential physiological problems caused by artificial sweeteners,” Marion Nestle, professor emeritus of nutrition at New York University, wrote in an email. “Researchers are discovering problems with one substance after another, now including xylitol.”

Although she believes the study should be repeated, it does suggest that xylitol may not be harmless. The benefits of artificial sweeteners in general are uncertain, she wrote.

“It’s increasingly looking like they pose risks,” she wrote. “I’d prefer to avoid them, but I don’t like the taste anyway.”

Rob van Dam, a professor of exercise and nutrition science at George Washington University, said the study’s findings were compelling and added to existing research on the risks of artificial sweeteners, but the researchers may not have been able to properly test the link between xylitol intake and heart risk because they used blood from people who had fasted. This means the blood likely contained xylitol that the body itself had produced through metabolism.

“So the question is, are these elevated xylitol levels really an indication that dietary xylitol intake is poor,” asked van Dam. “Or does it simply mean that there is something wrong with people’s metabolism that leads to higher xylitol levels?”

Recognizing this problem, the researchers conducted a follow-up experiment in which they gave ten people xylitol and water to see what happened to their platelets. They found that the platelets did indeed appear to aggregate more.

“I think in itself that wouldn’t be very concerning, but there’s a growing body of evidence that some of these artificial sweeteners may not be as harmless as we may have thought,” van Dam said. “If it was just something that people weren’t consuming in large quantities, nobody would really care. But the context is that hundreds of millions of people are exposed to this stuff, sometimes every day, so any evidence that raises concern is pretty relevant to public health.”

Given that the medical community generally recommends using sugar substitutes instead of sugar as an alternative for those who are overweight or have diabetes or metabolic syndrome, this study should be a warning sign, Hazen says.

“I hope this is a call to action and for colleagues to start looking into this matter. Because given the huge amounts of this stuff that we’re pumping into our food pyramid and thinking it’s safe, this is a major public health problem,” Hazen said.