E466 – Carboxymethyl Cellulose (Cellulose Gum)

Safety grading ORANGE – SOME CONCERNS

E466 (sodium carboxymethyl cellulose, often listed as cellulose gum) is widely permitted as a thickener and stabiliser. The overall regulatory baseline is reassuring: the European Food Safety Authority (EFSA) has assessed E466 and concluded there is no need for a numerical ADI (Acceptable Daily Intake) for the general population, and that there is no safety concern at reported uses and exposure levels. In the United States, sodium carboxymethylcellulose is listed as GRAS (Generally Recognized as Safe) for use in food under specific conditions.

However, E466 sits in a group of “non-absorbed emulsifiers and stabilisers” that has attracted scientific debate in the last decade, mainly around gut microbiota interactions. Because E466 is not meaningfully absorbed, it passes through the intestine where it can interact with mucus, microbes, and fermentation products. A randomized, controlled-feeding human study in healthy adults compared an additive-free diet with the same diet plus E466 at 15 g/day for a short period. The E466 group showed greater changes in gut microbiota composition, shifts in stool metabolites (including reduced short-chain fatty acids in some participants), and a subset experienced increased post-meal abdominal discomfort. Importantly, the study also reported that only some individuals showed more pronounced markers linked to mucus-layer disturbance, suggesting inter-individual sensitivity rather than a uniform effect.

This combination of (1) generally favorable regulator conclusions for typical dietary exposure, and (2) credible controlled evidence of microbiome and gastrointestinal effects at higher experimental doses in some people, is why E466 fits best as ORANGE – SOME CONCERNS rather than GREEN – SAFE. For most consumers, occasional exposure is unlikely to be a problem, but the current evidence supports a practical “moderation and context” approach, especially for people with sensitive digestion or inflammatory gut conditions.

Should you avoid E466?

You do not usually need to avoid E466 completely. If you rarely eat highly processed foods, your intake is likely to be low. Consider limiting E466-containing products if you have irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), unexplained bloating, or if you notice consistent symptoms after foods that contain “cellulose gum” or “carboxymethylcellulose.” As with many texture additives, the dose and the overall diet pattern matter more than a single ingredient in isolation.

For infants and people relying on special medical foods, it is sensible to follow product-specific medical guidance. Regulators have requested additional data for certain infant and special medical uses, which is a different evidence standard than general adult intake.

Common uses

Ice cream and frozen desserts: improves texture and reduces ice-crystal growth.
Low-fat dairy and “light” products: helps mimic mouthfeel by increasing viscosity.
Sauces, dressings, and gravies: thickens and stabilises emulsions.
Bakery fillings and glazes: prevents separation and improves consistency.
Plant-based drinks: keeps particles suspended and reduces sedimentation.
Instant soups and powdered mixes: improves rehydration and texture.

Common names / synonyms

Carboxymethyl cellulose
Sodium carboxymethyl cellulose
Carboxymethylcellulose sodium
Cellulose gum
CMC (carboxymethyl cellulose)

What is it?

E466 is a modified cellulose derivative. Cellulose is the main structural polysaccharide in plants and is built from long chains of glucose units linked by beta-1,4 bonds. Humans lack the enzymes needed to digest cellulose efficiently, so it behaves like dietary fiber. To make E466, manufacturers start with purified cellulose (typically from wood pulp or cotton linters) and chemically introduce carboxymethyl groups onto the cellulose chain. The result is carboxymethyl cellulose, usually used in food as its sodium salt (sodium carboxymethyl cellulose).

The key functional property of E466 is that it dissolves in water and forms a viscous solution. This viscosity depends on the molecular weight and the degree of substitution (how many carboxymethyl groups are attached). In practical food formulation terms, that means E466 can thicken liquids, keep droplets or particles evenly dispersed, and improve stability during freeze-thaw cycles. It is typically used at low concentrations, often well below one percent, but it can still produce noticeable texture changes.

From a biological perspective, E466 is considered “largely non-absorbed,” so most of it passes through the gut. Some fraction may be fermented by intestinal microbiota, and its viscosity can also influence gut transit time and how nutrients mix with digestive fluids. These mechanisms help explain why very high intakes can cause mild, reversible gastrointestinal effects such as bloating or looser stools in some people. They also explain why microbiome-focused research has looked at E466 and similar emulsifiers as potential modifiers of the intestinal environment.

Where it’s allowed (EU vs US)

In the EU, E466 is authorised as a food additive with defined conditions of use, and it appears in the European Commission’s food additives database. In the US, sodium carboxymethylcellulose is listed in the Code of Federal Regulations as a GRAS substance for food use under specified conditions.