Many people try to avoid sugar for health reasons. They may choose sugar-free foods that contain sweeteners like aspartame (found in Equal), sucralose (Splenda), or sugar alcohols such as sorbitol.
These are often seen as healthier options. But new research suggests that some of these sweeteners may not be as safe as we once thought—especially sorbitol.
A new study from Washington University in St. Louis raises concerns about the sugar alcohol sorbitol. The research comes from Professor Gary Patti and was published in the journal Science Signaling. Patti’s team found that sorbitol may act very much like fructose, a type of sugar that has been linked to liver problems and even cancer growth.
Sorbitol is very close in structure to fructose. The body can even convert sorbitol into fructose. In their study, the researchers used zebrafish to understand what happens when people eat foods that contain glucose and sorbitol.
They found that the gut can produce sorbitol after a meal, and this sorbitol travels to the liver, where it becomes a type of fructose. This is worrying because fructose has already been linked to liver damage in many other studies.
For years, scientists believed that sorbitol was only a problem for people with diabetes. In those cases, high blood sugar could cause the body to make too much sorbitol. But this new study shows that even healthy people can produce large amounts of sorbitol after eating, especially if they eat a lot of glucose at the same time.
One important part of this research focuses on gut bacteria. The researchers discovered that certain types of bacteria, such as Aeromonas, can break down sorbitol into harmless byproducts. If someone has enough of these good bacteria in their gut, they may not have any problems with small amounts of sorbitol.
However, if these bacteria are missing or overwhelmed, sorbitol can build up and go to the liver, where it may cause harm.
The study also warns that even people with healthy gut bacteria might be at risk if they eat too much sorbitol or glucose. At some point, the body and the bacteria can no longer keep up. This overload may lead to liver stress, especially in people who eat many processed or “sugar-free” foods.
Even the study’s lead researcher was surprised by how common sorbitol is in everyday foods. He discovered that one of his favorite protein bars had a high amount of it. Today, many packaged foods contain more than one type of sweetener, making it hard for people to avoid these ingredients.
This research shows that sugar alcohols like sorbitol may not be as harmless as we once believed. Instead of being removed easily by the body, sorbitol can end up in tissues throughout the body and may cause problems, especially in the liver.
The big takeaway is that there is no perfect substitute for sugar. Many of the body’s systems are connected, and changing one part can have effects elsewhere. As Professor Patti put it, “There is no free lunch” when it comes to using sugar replacements.
This study was supported by the National Institutes of Health. More research is needed to understand exactly how gut bacteria interact with sorbitol and how different diets affect this process. But for now, it may be wise to think twice before assuming that sugar-free always means safe.
If you care about liver health, please read studies that refined fiber is link to liver cancer, and the best and worst foods for liver health.
For more health information, please see recent studies about how to boost your liver naturally, and simple ways to detox your liver.
The study is published in Science Signaling.
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