Scientists have issued a serious health warning concerning a popular sweetener found in many everyday items, linking it to a potentially fatal liver condition.
The Hidden Danger in Sugar-Free Products
According to a new study, sorbitol, a common ingredient used to sweeten chewing gum, diet soft drinks, toothpaste, and countless low-calorie snacks, may contribute to the development of metabolic dysfunction-associated steatotic liver disease (MASLD). This is the condition formerly known as non-alcoholic fatty liver disease.
The research, published in the journal Science Signalling, indicates that consuming sorbitol can lead to a dangerous buildup of the substance in the liver, but only when a person's gut microbiome is out of balance.
How a Disrupted Gut Leads to Liver Damage
The study examined the gut microbiome of zebrafish, which, like humans, relies on beneficial gut bacteria for proper digestion. Researchers discovered that when these gut bacteria were depleted, sorbitol—which is also naturally produced by the body when processing glucose—traveled directly to the liver.
This caused fatty liver disease even though the fish were on a normal diet. Under healthy conditions, gut bacteria break down sorbitol before it can reach the liver, preventing harm. However, this crucial protective mechanism fails when the microbiome is weakened.
Dr. Gary Patti of Washington University explained that sorbitol is chemically very close to fructose, a sugar already known to worsen liver disease. He noted, "If you don't have the right bacteria, that's when it becomes problematic," because the sorbitol bypasses the gut and reaches the liver intact, where it is converted into a harmful substance.
Widespread Implications and Silent Symptoms
This finding is particularly concerning given the prevalence of MASLD. The disease already affects up to one in five people in the UK, but experts suspect the real figure could be as high as 40 percent, with the vast majority of cases going undiagnosed.
Many people with MASLD experience no obvious symptoms, meaning the condition is often discovered by accident during routine medical tests. When symptoms do appear, they can include fatigue, abdominal discomfort, or a general feeling of being unwell. In more advanced stages, the disease can cause jaundice, swelling, easy bruising, and confusion.
The researchers warned that even people with generally healthy gut bacteria are at risk if they consume excessive amounts of either sugar or sorbitol, as this can overwhelm the system and still allow sorbitol to reach the liver.
While the study raises significant concerns, experts also urge caution. They note that the well-documented harms of excessive sugar consumption are still a major public health issue. The long-standing assumption that sugar-free alternatives are universally healthier "may not hold true," and more research is needed to fully understand the complex relationship between artificial sweeteners and metabolic diseases.
