A new study has linked a popular food additive to colon cancer in mice.
Researchers from Georgia State University’s Institute for Biomedical Sciences have linked emulsifiers, an additive in many processed foods, especially frozen desserts, baked goods, sauces and dressing, to colon cancer by running studies with mice.
It is believed that intestinal microbiota—the population of microbe living in the intestine—is a key factor in driving colorectal cancer, as well as Crohn’s Disease and ulcerative colitis—the two most common forms of inflammatory bowel disease (IBD).
Another condition—low-grade inflammation—was also shown to be associated with altered gut microbiota composition and metabolic disease and is observed in many cases of colorectal cancer.
The study shows that dietary emulsifiers might be partially responsible for this association.
Study co-author Andrew Gewirtz, Ph.D., explained in an interview with R&D Magazine the dangers the study results show.
“We think that synthetic dietary emulsifiers and perhaps other food additives, few of which have been tested for their potential, promote chronic low-grade inflammation, which is increasingly being appreciated to drive a range of diseases including obesity, type 2 diabetes and cancer,” he told R&D.
“Hence, if consumed frequently for a prolonged period, these synthetic emulsifiers might have a considerable negative impact upon a person’s health.”
During the study the researchers fed mice with two commonly used emulsifiers—polysorbate 80 and carboxymethylcellulose—at doses seeking to model the broad consumption of the numerous emulsifiers that are incorporated in processed food. This resulted in the composition of the gut microbiota in the mice in a manner that made it more pro-inflammatory, creating a niche favoring cancer induction and development.
Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which activate pro-inflammatory gene expression by the immune system.
The researchers observed using well-established models that dietary emulsifier consumption was sufficient to make animals more susceptible to developing colonic tumors because this created and maintained a pro-inflammatory environment associated with an altered intestinal microbiota, characterized by an increased pro-inflammatory potential.
The study shows that emulsifier-induced alterations in the microbiome were necessary and sufficient to drive alterations in the intestinal epithelial cells’ homeostasis, which is thought to govern tumor development.
Microbiota plays a central role in tumor development because the effects of consuming emulsifiers were eliminated in mice devoid of microbiota and transplanting microbiota from emulsifier-treated mice to germ-free mice was sufficient to transfer alterations in intestinal epithelial cells’ homeostasis.
Gewirtz said they are currently testing the results on humans, as well as trying to develop a replacement for emulsifiers, which is added to processed foods to aid texture and extend shelf life.
“At present we’ve tested two synthetic emulsifiers,” he added. “Our preliminary studies on others, notably lecithin, suggests its effects will be comparatively modest.
“We are currently planning studies in humans in collaboration with researchers at the University of Pennsylvania focusing initially on CMC since it is very widely used but not well studied. If our findings from mice are recapitulated in humans it would argue that use of this product by the food industry should be curtailed and that many food additives need to be tested in models that consider low-grade inflammation and the extent to which an additive might impact the gut microbiota.”
The American Cancer Society estimates that there are 95,000 new cases of colon cancers and 39,000 new cases of rectal cancer in 2016.
Gewirtz comments were on behalf of himself and fellow co-author Benoit Chassaing, Ph.D. Emilie Viennois, Ph.D., and Didier Merlin, Ph.D., are also credited as co-authors on the study.