Sorbitol, a Common Sugar Alcohol, may Contribute to Liver Disease
A recent study from Washington University in St. Louis has revealed a potential link between sorbitol, a widely used sugar alcohol found in “low-calorie” foods and naturally occurring in fruits, and the development of steatotic liver disease – a condition affecting approximately 30% of adults globally. The research challenges the assumption that choice sweeteners are necessarily healthier than customary sugar.
The surprising finding centers on sorbitol’s close chemical relationship to fructose. Researchers, led by Dr. Maurizio Patti, discovered that as sorbitol is only “one conversion away from fructose,” it can trigger similar detrimental effects in the liver.
Experiments utilizing zebrafish demonstrated that sorbitol can be produced in the gut from glucose after a meal, even in individuals without diabetes. While the enzyme responsible for sorbitol production requires relatively high glucose levels to function, these levels are commonly reached in the gut following food intake. Sorbitol can also be directly consumed through foods like candy, gum, and stone fruits.
The fate of sorbitol within the body depends heavily on the composition of an individual’s gut microbiome. Certain Aeromonas bacterial strains effectively degrade sorbitol into harmless byproducts. Though, if these beneficial bacteria are absent or overwhelmed, sorbitol remains intact and is transported to the liver, where it is indeed converted into a fructose derivative.
While gut bacteria can typically manage modest levels of sorbitol, problems arise when consumption – either from glucose-derived sorbitol or direct dietary intake - exceeds their capacity. Even individuals with the beneficial bacteria may experience issues with excessive sorbitol loads.
The study highlights the complexity of finding truly “sugar-free” alternatives, as many processed foods contain multiple sweeteners. Dr. Patti noted his own surprise at discovering high levels of sorbitol in a commonly consumed protein bar.
further research is planned to fully elucidate the mechanisms by which gut bacteria clear sorbitol and to determine the extent to which sorbitol accumulates in tissues throughout the body. The findings underscore the idea that avoiding negative metabolic consequences requires a nuanced approach, as “there is no free lunch” when seeking sugar alternatives.
This research was supported by the National Institutes of Health.
