At it’s most basic definition, carrageenan is an indigestible polysaccharide derived from red algae. It’s often used as a thickener or stabilizer in many of today’s industrialized foods. But is it Paleo?
When we talk about carrageenan in our food, what we’re really talking about is undegraded carrageenan. Degraded carrageenan is not approved for use in food, although the term carrageenan is often used to refer to both.
Much of the alarm surrounding carrageenan comes from a review of about 45 animal studies that implicated carrageenan in the formation of ulcers and cancer. However, most of these studies used degraded carrageenan (also known as poligeenan). Carrageenan has been shown to accelerate cancer formation, but only when combined with a known carcinogen (source).
Possible Harm to Digestion
Some animal studies have found carrageenan can cause intestinal damage, while other studies found no intestinal damage. The results suggest it is highly dependent on the species, which makes it more difficult to determine the effect on humans without directly studying human participants.
On the other hand, the animal studies tend to add the carrageenan to the animals’ drinking water, which could have a more severe effect than consuming it with food (because carrageenan interacts with protein molecules). The studies also tend to include carrageenan in much higher doses than we tend to consume it (1% of the total diet, as opposed to 1% of our can of coconut milk, for example).
Caution Without Fear
At the end of the day, it doesn’t look like there’s any reason to run screaming from anything that includes carrageenan on its list of ingredients. On the other hand, there is evidence to suggest you might want to exercise caution. Cooking all your own meals and buying only whole foods with one ingredient is always the best way to go.