Carboxymethylcellulose
Emulsifier with debated gut microbiome effects.
- Category
- Emulsifiers, Humectants, Stabilisers, Thickeners
- Vegan
- Yes
- Vegetarian
- Yes
What it is
Carboxymethylcellulose (E466 / CMC), often just called cellulose gum, is a synthetic modification of natural plant fibre. It forms a thick, clear, slimy gel when mixed with water.
How it is used in food
Modified cellulose used in everything from ice cream to toothpaste.
Commonly found in- Ice creams and diet milkshakes
- Gluten-free baking (to mimic the elasticity of gluten)
- Toothpaste
- Eye drops (as artificial tears)
Health and safety
Featured with polysorbate 80 in the 2015 Nature microbiome study; a small 2021 human trial also showed gut-bacteria shifts.
For decades, E466 was considered an entirely inert, harmless fibre that simply passed through the body. However, a landmark 2015 study in Nature, alongside recent human trials, has brought it under intense scrutiny.
Gut microbiome disruption
Studies indicate that CMC can degrade the protective mucus lining of the gut and alter the microbiome, potentially triggering low-grade inflammation and metabolic issues.
Kept under active research due to these shifts.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted. |
| European Union EFSA / European Commission |
Permitted | Authorised for food use under EU regulations (Annex II). |
| United States FDA (Food and Drug Administration) |
Permitted | GRAS (Generally Recognized as Safe). |
Identification on labels
- E-number
- E466
Also printed asCellulose gum · CMC · Sodium carboxymethylcellulose
Alternatives to this additive
- E412: Guar gum — A more natural, less chemically-processed hydrocolloid that serves similar thickening purposes.
How it is made
It is made by reacting natural cellulose (often from cotton linters or wood pulp) with chloroacetic acid to make it soluble in water.
- Alkalization — Wood pulp or cotton is steeped in sodium hydroxide (lye).
- Etherification — It is reacted with chloroacetic acid, transforming the insoluble wood fibre into a water-soluble gel.
Worth knowing
Very wide-ranging industrial use.
Conclusion
While global regulators still consider E466 safe, emerging microbiome science suggests that these modern "slimy" emulsifiers may be contributing to the rise of inflammatory bowel diseases.
References
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Open the appEntry last reviewed 2026-07-28.
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