Scientists discover a hidden problem with this popular sugar substitute

Sorbitol, a sugar alcohol commonly used in sugar-free candy, gum, and other low-calorie foods, may not be as harmless as it seems. Researchers at Washington University in St. Louis found that the body can convert sorbitol into a form of fructose in the liver, potentially triggering some of the same harmful metabolic effects linked to fructose.

Scientists discover a hidden problem with this popular sugar substitute. Science News from research organizations Scientists discover a hidden problem with this popular sugar substitute Date: September 6, 2026 Louis Summary: Sorbitol, a sugar alcohol commonly used in sugar-free candy, gum, and other low-calorie foods, may not be as harmless as it seems. Common examples include aspartame, the sweetener used in Equal packets, sucralose (Splenda), and sugar alcohols such as sorbitol.

But growing research is complicating the idea that these alternatives are automatically healthier. A new study suggests that sorbitol, in particular, may have metabolic effects that make it less harmless than many people assume. Sorbitol May Be One Step Away From Fructose The research, published recently in Science Signaling, builds on a line of research from Gary Patti's laboratory at Washington University in St.

Louis examining how fructose affects the liver and other parts of the body. Patti, the Michael and Tana Powell Professor of Chemistry, in Art & Sciences, and of genetics and medicine, at WashU Medicine, has previously investigated what happens when fructose is processed by the liver. His earlier work showed that the products of fructose metabolism can be exploited by cancer cells to promote their growth.

Other research has identified fructose as an important contributor to steatotic liver disease, a condition involving excess fat accumulation in the liver that affects about 30% of adults worldwide. The new findings raise concerns about sorbitol because of how closely it is connected to fructose metabolically.

Patti described sorbitol as being essentially "one transformation away from fructose," meaning the body can convert it into a closely related form that may produce similar effects. From the Gut to the Liver The researchers performed experiments in zebrafish to trace what happens to sorbitol inside the body.

Sorbitol is commonly added to "low-calorie" candy and chewing gum, but it also occurs naturally in stone fruits. The team found that sorbitol does not have to come directly from food.

Enzymes in the intestine can also produce it from glucose after a meal. Once sorbitol is present, its eventual fate can depend on how much glucose and sorbitol has been consumed and on the types of bacteria living in the gut.

That creates several possible routes through which fructose-related compounds can ultimately appear in the liver. Much of the previous research on sorbitol metabolism has centered on diseases such as diabetes.

Under those conditions, unusually high glucose levels can drive the body to produce larger amounts of sorbitol. The enzyme responsible for making sorbitol has a relatively low affinity for glucose.

In simple terms, it generally does not become very active until glucose concentrations rise substantially. For that reason, sorbitol production has historically been associated with diabetes, where blood glucose can reach high levels.

The zebrafish experiments, however, showed that diabetes is not required. Even under healthy conditions, glucose concentrations inside the gut can become high enough after eating to trigger significant sorbitol production in the intestine.

"It can be produced in the body at significant levels," said Patti. "But if you have the right bacteria, turns out, it doesn't matter." Gut Bacteria Can Act as a Protective Filter Certain bacteria appear to prevent sorbitol from becoming a problem.

Sorbitol-degrading Aeromonas bacterial strains can consume the sugar alcohol and convert it into a harmless bacterial byproduct. That microbial cleanup process may determine whether sorbitol stays in the gut or travels farther into the body.

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with qualified healthcare professionals for medical decisions and treatment options.