Researchers have discovered that common food thickeners, long believed to pass through the digestive system intact, can actually be digested by gut bacteria. A study published in the Journal of Bacteriology found that artificial cellulose derivatives, commonly used in foods like ketchup and salad dressing, can be broken down by enzymes activated by natural polysaccharides found in fruits, vegetables, and cereals.
The complex structure of these thickeners makes them difficult for gut bacteria to digest. However, when gut bacteria are “primed” with natural polysaccharides, they can activate enzymes that break down artificial cellulose molecules. This discovery challenges conventional wisdom and highlights the importance of further research into the physical, chemical, and biological effects of digestion.
The study’s findings suggest that more work is needed to explore the potential effects of this ability on nutrition in people. Researchers plan to investigate whether this ability exists in a wider range of human gut bacteria and potentially explore its impact on nutrition. With this new knowledge, consumers can better understand how their gut bacteria are helping to break down their food, from green salads with sweet dressings to everyday foods like ketchup and toothpaste.
Source: Deepesh Panwar et al, Artificial cellulose derivatives are metabolized by select human gut Bacteroidota upon priming with common plant β-glucans, Journal of Bacteriology (2025). DOI: 10.1128/jb.00198-25
Source: https://phys.org/news/2025-08-common-food-thickeners-thought-digested.html