Gut bacteria digest common thickeners

New research shows gut bacteria can digest cellulose derivatives when primed with natural plant polysaccharides.

Common cellulose-based food thickeners become digestible by gut bacteria

Researchers at the University of British Columbia report that cellulose-based thickening agents used in foods like ketchup, dressings and toothpaste can be metabolized by certain gut bacteria. The work, published in the Journal of Bacteriology, found that the additives are broken down when gut microbes are exposed to plant polysaccharides that normally help digest dietary fiber. This primes enzymes on some gut bacteria, including members of Bacteroidota, to attack artificial cellulose molecules.

The study used in vitro methods. It shows that digestion requires a dietary context where natural polysaccharides activate enzymes produced on bacterial surfaces, enabling cellulose derivatives to serve as a sugar source. The researchers stress that the safety of these additives remains established through years of testing, while calling for more work to understand possible effects on nutrition and the microbiome in real life. They note that lab tests may miss interactions because bacteria are often studied in isolation.

The finding challenges the idea that food additives are inert after swallowing. It shows the microbiome reshapes everyday ingredients when given the right signals. The result matters for nutrition science, product design, and labeling.

This is early work based on lab models. It remains to be seen how widespread the effect is across gut bacteria and what it means for real meals. The study points to a need for broader testing and for researchers to map how diet, microbes, and food additives interact in humans.

Highlights

The next steps will reveal more about how our meals and microbes share the same table.