What Is Carboxymethylcellulose?
Carboxymethylcellulose, or CMC, is a synthetic emulsifier used in processed foods. The FDA lists sodium carboxymethylcellulose, the sodium salt of carboxymethylcellulose, as generally recognized as safe when used in accordance with good manufacturing practice, and the Joint FAO/WHO Expert Committee on Food Additives placed it in a group of modified celluloses with an acceptable daily intake of "not specified" in 1989.
A small human trial raised questions. In a double-blind controlled-feeding study published in Gastroenterology and supported by NIH grants, Chassaing and colleagues gave healthy adults an emulsifier-free diet (9 people) or the same diet with 15 grams a day of CMC added (7 people) for 11 days. Compared with controls, CMC modestly increased abdominal discomfort after meals, reduced the diversity of gut microbiota, and lowered short-chain fatty acids and free amino acids in stool.
The authors wrote that their results support the notion that broad use of CMC in processed foods may be contributing to more chronic inflammatory diseases by altering the gut microbiome and metabolome. That is a hypothesis drawn from a small study, not a regulatory finding.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Regulatory filingUnder 21 CFR 182.1745, sodium carboxymethylcellulose, the sodium salt of carboxymethylcellulose, is generally recognized as safe when used in accordance with good manufacturing practice. US FDA, 21 CFR 182.1745 (eCFR) ↗
- Government sourceJECFA's 1989 evaluation gave sodium carboxymethyl cellulose an acceptable daily intake of not specified, as part of a group ADI for modified celluloses. JECFA, World Health Organization ↗
- StudyIn a double-blind controlled-feeding study, healthy adults ate emulsifier-free diets (9 people) or the same diet with 15 grams a day of CMC (7 people) for 11 days. Gastroenterology, via PubMed Central ↗
- StudyCompared with controls, CMC modestly increased abdominal discomfort after meals, reduced gut microbiota diversity, and lowered short-chain fatty acids and free amino acids in stool. Gastroenterology, via PubMed Central ↗
- StudyThe authors said their results support the notion that broad use of CMC in processed foods may be contributing to chronic inflammatory diseases by altering the gut microbiome and metabolome. Gastroenterology, via PubMed Central ↗
- StudyThe CMC feeding study was supported by National Institutes of Health grants and by the Max Planck Society. Gastroenterology, via PubMed Central ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.