Carrageenan is a complex sulfated polysaccharide isolated from algae that is commonly used as a binding agent in foods including ice creams, pastries, and breads. It is also used experimentally to induce inflammation and stimulate cancer growth and invasion in tissues.

Even very low concentrations of carrageenan can stimulate cancer invasion. It can also increase inflammation within the GI tract, a major problem for people with inflammatory bowel diseases.

Like a number of substances that stimulate intense inflammation, it also suppresses beneficial immunity, including cellular immunity, which is critical for fighting infections and suppressing cancer.

The only way to avoid carrageenan is to avoid all processed foods.