Common Food Additive Alters Your Microbiota, Triggers Severe Diseases: Scientists

New clinical research indicates that a widely used food additive, an emulsifier called  carboxymethylcellulose, or “CMC” alters the intestinal environment of healthy persons, adversely affecting levels of beneficial bacteria and nutrients which triggers severe diseases


Carboxymethylcellulose (CMC) is a synthetic member of a widely used class of food additives, termed emulsifiers, which are added to many processed foods to enhance texture and promote shelf life. CMC has not been extensively tested in humans but has been increasingly used in processed foods since the 1960s. It had long been assumed that CMC was safe to ingest because it is eliminated in the feces without being absorbed. However, increasing appreciation of the health benefits provided by bacteria that normally live in the colon, and thus would interact with non-absorbed additives, has led scientists to challenge this assumption.”

Study overview

The research team performed a randomized controlled-feeding study in healthy volunteers. Participants, housed at the study site, consumed an additive-free diet or an identical diet supplemented with carboxymethylcellulose (CMC). Because the diseases CMC promotes in mice take years to arise in humans, the researchers focused here on intestinal bacteria and metabolites. They found that CMC consumption changed the make-up of bacteria populating the colon, reducing select species. Furthermore, fecal samples from CMC-treated participants displayed a stark depletion of beneficial metabolites that are thought to normally maintain a healthy colon.

CMC effect on Microbiota 2

Lastly, the researchers performed colonoscopies on subjects at the beginning and end of the study and noticed that a subset of subjects consuming CMC displayed gut bacteria encroaching into the mucus, which has previously been observed to be a feature of inflammatory bowel diseases and type 2 diabetes. Thus, while CMC consumption did not result in any disease per se in this two week study, collectively the results support the conclusions of animal studies that long-term consumption of this additive might promote chronic inflammatory diseases.

CMC effect on Microbiota

Results overview

“Experiments in mice found that CMC, and some other emulsifiers, altered gut bacteria resulting in more severe disease in a range of chronic inflammatory conditions, including colitis, metabolic syndrome and colon cancer.

“It certainly disproves the ‘it just passes through’ argument used to justify the lack of clinical study on additives.”

-Dr. Andrew Gewirtz, one of the paper’s senior authors, Georgia State University


As always, read the ingredients labels on all processed foods before deciding to put them into your shopping cart and avoid purchasing food products with “CMC‘ (or “Carboxymethylcellulose” or “Cellulose Gum“) in the ingredients list.

Journal Reference:  Benoit Chassaing, Charlene Compher, Brittaney Bonhomme, Qing Liu, Yuan Tian, William Walters, Lisa Nessel, Clara Delaroque, Fuhua Hao, Victoria Gershuni, Lillian Chau, Josephine Ni, Meenakshi Bewtra, Lindsey Albenberg, Alexis Bretin, Liam McKeever, Ruth E. Ley, Andrew D. Patterson, Gary D. Wu, Andrew T. Gewirtz, James D. Lewis, Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome, Gastroenterology Journal,  Open Access, Published:November 10, 2021, Reference:YGAST 64699.  DOI: pdf:  Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome