The study offers the first detailed look at how our gut bacteria digest these food additives, aided by natural polysaccharides found in our diets.
Many everyday foods contain cellulose-based thickening agents, and new research shows that they are not as indigestible as once believed.
A team at the university of British Columbia has found that certain gut bacteria can use these large molecules as a food source, a capability previously thought to be impossible.
This process relies on enzymes that the body normally uses to break down dietary fiber.
“Researchers assumed that these thickening agents, which are artificial derivatives of natural cellulose, just pass right through the digestive system unaltered,” says Dr. Deepesh Panwar, a postdoctoral fellow at the Michael Smith Laboratories and lead author of the study published in the Journal of Bacteriology.
“But our study provides a first glimpse at how these food additives are actually digested by our gut bacteria thanks to natural polysaccharides in our diets.”
The complex molecular design of cellulose derivatives is what makes them effective thickeners in products such as ketchup, salad dressing, and even toothpaste.
That same complexity makes it difficult for gut bacteria to break them apart, which is why in higher amounts they are also used as laxatives.
This new in vitro study, however, shows that if our gut bacteria are ‘primed’ with natural polysaccharides – long chains of sugars found in fruits, vegetables, and cereals – the cellulose derivatives can be digested.
This is because the natural polysaccharides activate enzymes that are produced on bacteria cell surfaces that can also break down artificial cellulose molecules.
The findings don’t challenge the fact that these compounds are safe to consume, proven by years of testing and history of use. However, the new research suggests that more work should be done to explore the physical, chemical and biological effects of the digestion of cellulose derivatives by gut bacteria.
