Agar-Agar vs Carboxymethylcellulose (CMC): which is worse?

What is Agar-Agar?

Agar-agar is a gelatinous polysaccharide extracted from red algae (primarily Gelidium and Gracilaria species). Unlike gelatin, it sets at room temperature and does not melt until heated to approximately 85°C. It is widely used in Asian cuisine and as a vegan gelatin substitute globally. It also functions as a growth medium in microbiology.

What is Carboxymethylcellulose (CMC)?

Carboxymethylcellulose (CMC) is a cellulose derivative produced by reacting cellulose (from wood pulp or cotton) with sodium chloroacetate under alkaline conditions. As cellulose gum, it is highly water-soluble and provides viscosity and stability at low concentrations. It is one of the most widely used food hydrocolloids globally.

Documented risks

Agar-Agar: Generally recognized as safe with no identified health risks at food use levels. Agar is not significantly digested and acts as a bulk dietary fiber. Very large amounts can cause constipation or intestinal obstruction if consumed without adequate water. EFSA confirmed its safety in 2016.

Carboxymethylcellulose (CMC): A 2015 study published in Nature (Chassaing et al., Georgia State University) found that dietary CMC at levels comparable to typical food exposure disrupted the gut microbiome in mice, reducing protective mucus layer thickness, promoting low-grade inflammation, and accelerating colitis and metabolic syndrome in genetically predisposed animals. A 2022 randomized controlled trial (CARGO trial, published in Gastroenterology) in healthy humans confirmed that CMC disruption of gut microbiota composition was observed. EFSA and FDA have not changed approval status, but these findings have generated significant scientific discussion.