Scientists Warn Popular ‘Sugar-Free’ Sweetener May Trigger Deadly Liver Disease

S Scientists have issued a major health warning after new research linked a widely used “sugar-free” sweetener to a potentially fatal liver condition. The sweetener, sorbitol—commonly found in chewing gum, diet drinks, sugar-free snacks and a wide range of low-calorie foods—may increase the risk of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease.

The study suggests that sorbitol can accumulate in the liver when the gut microbiome is weakened or disrupted, leading to dangerous levels of fat buildup. MASLD is already one of the most common liver diseases globally. While estimates show that around one in five people in the UK may have the condition, some experts warn that the true figure could be as high as 40 percent, with many cases going undiagnosed.

Published in Science Signalling, the research investigated how sorbitol behaves in the body using zebrafish as a model. Scientists focused on the gut microbiome—the network of beneficial bacteria responsible for digestion and nutrient breakdown—which plays a crucial role in shielding the liver from harmful substances.

The findings revealed that when these protective gut bacteria were depleted, sorbitol produced naturally during glucose processing bypassed the gut’s usual breakdown process and travelled directly to the liver. This unexpected accumulation triggered fatty liver disease, despite the fish being fed a normal, healthy diet.

Under typical conditions, gut bacteria efficiently break down sorbitol before it enters the bloodstream, preventing harm. But when the microbiome is weakened—due to illness, medication, poor diet or other factors—this safeguard collapses, allowing sorbitol to reach the liver unprocessed.

Researchers say the results provide important insight into how diet, sweeteners and gut health interact, and raise urgent questions about the safety of commonly consumed sugar-free products. They warn that the findings could have significant implications for public health, especially as more people turn to low-calorie and sugar-free alternatives in efforts to reduce sugar intake.