Researchers at Washington University in St. Louis have released a new study that questions the safety of one of the most popular sugar-free sweeteners. They found that sorbitol, which is often used in “diet” and “sugar-free” foods, might play a role in causing fatty liver disease in some situations.
Sorbitol is a sugar alcohol that is commonly added to products like chewing gum, protein bars, toothpaste, cough syrups, and snacks for people with diabetes because it has fewer calories than regular sugar. It also occurs naturally in fruits like apples, pears, peaches, and prunes. For a long time, it has been seen as a safer choice than regular sweeteners, especially for those watching their blood sugar.
But the new research shows that the situation might not be so simple.
The study, which appeared in the journal Science Signaling, found that sorbitol can cause effects in the body similar to fructose. Fructose is a sugar already linked to metabolic dysfunction-associated steatotic liver disease, or MASLD. This condition, once called fatty liver disease, affects millions of people worldwide and is becoming more common in younger adults.
The researchers did their experiments on zebrafish, which are often used in medical studies because their metabolism is similar to that of humans. They found that when the fish had fewer gut bacteria, they showed signs of fatty liver disease even though they ate a normal diet.
The scientists traced the problem to sorbitol. The study explains that our bodies can naturally produce sorbitol after we eat glucose. Normally, healthy gut bacteria break down most of the sorbitol before it gets to the liver. But if gut bacteria are disrupted, sorbitol can reach the liver and be metabolised into compounds related to fructose metabolism, which can cause fat to build up and affect how the liver works.
Senior author Gary Patti said the team was surprised to find that sorbitol acts a lot like fructose in the body. He also said that certain gut bacteria seem to be important in preventing potential harm.
The researchers found that some types of Aeromonas bacteria can safely break down sorbitol in the gut. When these bacteria were put back into the zebrafish, the fish’s liver health got much better. However, experts warn that these results are early, and more studies in humans are needed before making any strong claims.
It’s important to note that the researchers are not telling people to stop eating sorbitol or to worry about having sugar-free foods once in a while. Their experiments used high amounts and were done in animals, not people. Still, the study adds to the idea that artificial sweeteners and sugar substitutes might not always be as safe as we once thought.
The results also show that gut health has a big impact on how our bodies handle food. More and more, scientists think that two people eating the same foods can have very different health results because of the bacteria in their guts.
As sugar-free products become more popular around the world, this new research might spark more conversations about how artificial sweeteners affect our long-term health and whether some so-called healthier options need closer scrutiny.
