Sorbitol may convert to fructose in the liver, posing metabolic risks
Researchers at Washington University found that the sugar alcohol sorbitol can be converted into a form of fructose in the liver, potentially triggering harmful metabolic effects similar to those of fructose. The study, conducted in zebrafish, suggests that sorbitol is essentially one transformation away from fructose. This raises concerns about the safety of sorbitol, commonly used in sugar-free products.
The investigation, published in *Science Signaling*, utilized zebrafish to track sorbitol's metabolic pathway. Contrary to earlier assumptions that significant sorbitol generation only occurs under diabetic conditions, the researchers observed that normal post-meal glucose levels within the gut are sufficient to stimulate its production. This endogenous synthesis adds a new dimension to dietary intake.
The study also highlighted the role of gut microbiota as a potential safeguard. Specific bacterial strains can degrade sorbitol, acting as a biological filter that may mitigate its conversion to fructose. This finding suggests that individual variations in gut flora could influence metabolic risk, while prior work has already linked fructose processing to liver fat accumulation and cancer cell proliferation.
The findings could reshape dietary recommendations for individuals relying on sugar-free products to manage weight or diabetes. If sorbitol is metabolized into fructose, it may contribute to liver strain and metabolic syndrome in susceptible populations, particularly those lacking protective gut bacteria. Consumers might need to scrutinize ingredient labels more carefully, while food manufacturers could face pressure to reassess the safety of this common sweetener. However, the implications remain preliminary, requiring human studies to confirm the zebrafish results.