The common sugar-free sweetener sorbitol may damage your liver in the same way as the older sweetener fructose, researchers found.
Fructose, coming in at four calories per gramme, is popularly used in soft drinks and processed foods because it does not interact with blood insulin.
However, it was previously found to trigger processes linked to fatty liver disease in people without a history of drinking alcohol, affecting up to a quarter of adults and a growing number of younger people.
The most surprising finding from the current work is that because sorbitol is essentially “one transformation away from fructose”, it can induce similar effects, said study senior author and Washington University School of Medicine professor of chemistry, genetics and medicine Dr Gary Patti in a university press release.
Gut microbes play a key role.
“If you have the right bacteria, turns out, it doesn’t matter,” he said.
“However, if you don’t have the right bacteria, that’s when it becomes problematic.
“Because in those conditions, sorbitol doesn’t get degraded, and as a result, it is passed on to the liver.”
While examining zebrafish, whose digestive processes resemble those of humans, the researchers found that the fishes with gut biota depleted by antibiotics converted sorbitol into fructose in the liver, leading to an unhealthy build-up of fat in the organ.
The liver is the largest organ inside the body and is essential to digesting food, storing energy and clearing poisons from the blood.
As fatty liver has few symptoms, most people aren’t diagnosed with this condition until it has advanced towards cirrhosis or liver cancer, according to MedlinePlus.
People with type 2 diabetes or prediabetic conditions are most at risk, along with factors like obesity, age, and high cholesterol and blood pressure.
Symptoms can include being excessively tired or having pain in the upper right part of your abdomen.
The research suggests that sorbitol and fructose can be as bad for your liver as excessive drinking – the other main cause of fatty liver disease – while a healthy gut biome helps protect your liver.
Regular, low levels of sorbitol – touted for its low-calorie count and marketed as diabetes-friendly – are not likely to cause harm, the researchers said.
However, excessive amounts could overwhelm the gut bacteria that convert it into a harmless byproduct, causing it to be processed by the liver into a form of fructose instead.
Consuming excessive amounts of sugar can also cause glucose to be converted into large amounts of sorbitol in the body, leading to the same situation.
The study was published in last October’s (2025) issue of the journal Science Signaling. – By Karl Hille/The Baltimore Sun/Tribune News Service
