Common food additive alters gut bacteria, promotes inflammation and colon cancer

 

 

Consuming emulsifiers drastically changed the composition of the gut microbiota...made it more pro-inflammatory

Emulsifiers added to most processed foods to improve texture and extend shelf life can alter intestinal bacteria in a way that promotes inflammation and colorectal cancer, according to a new study on mice.

The findings, published in the journal Cancer Research, show regular consumption of dietary emulsifiers in mice exacerbated tumour development.

The microbiota is also a key factor in driving Crohn’s and ulcerative colitis, the two most common forms of inflammatory bowel disease (IBD). IBD is known to promote colon tumourigenesis and gave rise to the term “colitis-associated cancer”. Low-grade inflammation is also associated with altered gut microbiota composition and metabolic disease, and is seen in many cases.

“The incidence of colorectal cancer has been markedly increasing since the mid-20th century,” said Dr Emilie Viennois, of Georgia State University’s Institute for Biomedical Sciences. Human genetics have not changed, suggesting a pivotal role for an environmental factor.

 Emulsifiers are detergent-like molecules incorporated into most processed foods that alter the composition of gut microbiota. The addition of emulsifiers to food seems to fit the time frame and had been shown to promote bacterial translocation across epithelial cells. The GSU team hypothesised that emulsifiers might affect the gut microbiota in a way that promotes colorectal cancer.

To test this possibility, the team fed mice with two very commonly used emulsifiers, polysorbate 80 and carboxymethylcellulose, at doses modelling human consumption of the emulsifiers in processed foods. They immediately saw drastic changes in species composition, making the microbiota pro-inflammatory and creating a niche associated with an altered proliferation/apoptosis (cell death) balance favouring cancer.

The effects of consuming emulsifiers were eliminated in mice devoid of microbiota (germ-free mice), and transplanting microbiota from emulsifier-treated mice to germ-free mice was sufficient to transfer alterations in intestinal epithelial cells’ homeostasis, suggesting a central role played by the microbiota in tumour development.