Carboxymethylcellulose

Carboxymethylcellulose, often listed as Cellulose Gum (E466), is a common food additive derived from plant cellulose, such as wood pulp. It has no nutritional value and is used as a thickener, stabilizer, and emulsifier to improve the texture and consistency of many processed foods. In fast food, it is frequently found in sauces, dressings, shakes, and baked goods to provide a creamy mouthfeel, prevent ingredient separation, and control ice crystal formation in frozen desserts . While major global regulators have long considered it safe, recent scientific studies have raised concerns about its potential to negatively affect gut health by altering intestinal bacteria.

Aliases / Common Names: Sodium carboxymethyl cellulose, Cellulose Gum, Sodium CMC, Carmellose, E466, INS 466. Regulatory Status & Exposure: Major global bodies, including the U.S. FDA (GRAS status) and WHO/JECFA (ADI "Not Specified"), consider CMC safe based on evidence that it is not absorbed by the body. An EFSA re-evaluation in 2018 found no safety concern at current use levels . This traditional safety assessment is now challenged by research focusing on the gut microbiome. A pivotal 2021 human trial used a dose of 15 g/day, a high but potentially achievable exposure for individuals with diets rich in processed foods.   Technical Evidence: The foundation of CMC's safety status—that it is inert because it is unabsorbed—is contradicted by recent findings. Animal studies since 2015 show CMC can disrupt the gut's protective mucus layer, alter the microbiome, and promote low-grade inflammation and metabolic syndrome. These concerns were elevated by a 2021 human controlled-feeding study where healthy volunteers consuming CMC experienced altered gut bacteria, a depletion of beneficial metabolites (e.g., short-chain fatty acids), and, in some individuals, bacterial encroachment into the gut lining—a hallmark of inflammatory disease . Furthermore, a large 2023 cohort study associated higher CMC intake with an increased risk of cardiovascular disease. Fast-Food Context: CMC is used to thicken sauces (McDonald's Tangy BBQ Sauce), prevent ice crystals in shakes (Burger King soft serve), and bind breadings (McDonald's Fish Filet Patty). Fast-food meals often contain a "cocktail" of multiple emulsifiers and thickeners (e.g., polysorbate 80, carrageenan, xanthan gum), whose combined effects on the gut microbiome are unstudied.   Sensitive Populations / Notes: Individuals with Inflammatory Bowel Disease (IBD) or a predisposition to gut inflammation may be particularly susceptible to CMC's effects. Safety data for infants under 16 weeks of age is lacking, a data gap noted by EFSA.

We assign the high tier using published research, regulatory guidance, and PRūF’s additive taxonomy. Restaurant usage is derived from public ingredient disclosures and mapped to menu items where this additive appears.