Carrageenan and CMC in intestinal inflammation
What it found
In animal studies, carrageenan and CMC consistently caused intestinal ulcers and inflammation like human IBD.
Human cell and microbiome studies support these findings, but human trials are unethical to conduct.
What they found
Studies in people
Diet and IBD link
A case-control study in Japan found that eating Western foods like bread, butter, and sausage was linked to higher ulcerative colitis risk. Another study found that a Western diet increased the likelihood of Crohn's disease in adolescent females.
Animal and lab studies
Animal studies show ulcers
In guinea pigs given degraded carrageenan in drinking water, 100% developed large intestine ulcers within 30 days. Rabbits, mice, and rats also developed ulcers with weight loss, anemia, diarrhea, and sometimes blood or mucus in feces.
Gut bacteria needed
Germ-free guinea pigs fed carrageenan for 6 months or more did not develop any intestinal lesions. Treating normal guinea pigs with an antimicrobial prevented ulcer formation, showing gut bacteria are needed for carrageenan to cause damage.
CMC alters bacteria
In mice, CMC increased bacteria adhering to the gut lining and changed the mix of gut bacteria. In a lab model of the human gut, CMC made the bacteria more pro-inflammatory within 1 day.
Human cells respond
Human intestinal epithelial cells exposed to carrageenan showed activation of inflammatory pathways and increased production of IL-8, a pro-inflammatory cytokine. Carrageenan also disrupted the tight junctions between cells.
Carrageenan blocks defense
Carrageenan inhibited the bacterial aggregating function of DMBT1, a molecule that helps prevent bacteria from invading intestinal cells. This suggests carrageenan may disrupt a natural mucosal defense.
What the authors conclude
“Carrageenan and CMC may trigger or magnify an inflammatory response in the human intestine but are unlikely to be identified as the sole environmental factor involved in the development of IBD or in disease recurrence after treatment.”
Also in their conclusions
- They conclude that carrageenan and CMC consistently cause intestinal ulcers in animal models that look like human IBD.
- They say these findings raise concern because these additives are widely consumed by children and childhood IBD is increasing.
- They call for further research to clarify the role of carrageenan and CMC in intestinal inflammation and to develop nutritional strategies that prevent IBD or maintain remission.
How it was done
The authors wanted to review whether the food additives carrageenan and CMC might play a role in the development of inflammatory bowel disease (IBD), since these additives are used to induce intestinal inflammation in animal models and are excluded from some diets that treat Crohn's disease.
They reviewed existing scientific literature on carrageenan and CMC, including animal studies, human cell studies, and human microbiome studies. They also looked at studies on diet and IBD in people.
What it can’t tell you
- Human trials directly testing carrageenan and CMC would be unethical, so most evidence comes from animals and lab studies.
- Animal and cell studies cannot prove that these additives cause IBD in people.
- The review cannot show how much carrageenan or CMC people typically eat or what effect that amount has.
Who paid
- Authors work at
- IWK Health Centre, Canada; Dalhousie University, Canada; Harvard T.H. Chan School of Public Health, USA
The paper
- Title
- The Role of Carrageenan and Carboxymethylcellulose in the Development of Intestinal Inflammation
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Martino JV, Van Limbergen J, Cahill LE (2017). The Role of Carrageenan and Carboxymethylcellulose in the Development of Intestinal Inflammation. Frontiers in pediatrics. doi:10.3389/fped.2017.00096Free full textPubMed 28507982DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error