NO! Carrageenan, which is present in many processed foods, including the trendy protein puddings of some brands, IS NOT A CARCINOGEN.

It is a sulfated polygalactan of large molecular weight, >200 kDa, produced by a family of algae, the red algae, and with gelatinizing and thickening properties exploited by the food industry. Safety studies have shown no toxicity associated with carrageenan, which is not even assimilated in the GI tract due to its indegistibility and large molecule size.

The confusion arises because of a product of its degradation, polygynin, which is associated with the development of tumors. Polygonin is not used as a food additive, nor is it of interest as it does not have the same thickening properties. Its use is limited to medical imaging, and less and less due to potential toxicity. The molecular weight is 10 times smaller, around 20 kDa, and it can actually be assimilated by the body.

But the degradation of carrageenan into polygenin DOES NOT OCCUR IN VIVOunless your stomach has a pH <1, which it doesn't, and reaches temperatures above 80°C for several hours. Which obviously does not happen. The degradation is by no means spontaneous, but laboratory induced under more extreme conditions. Older studies with obsolete techniques of low sensitivity suggested the possibility of the presence of carrageenan degradation products in foods, which has not been corroborated using more reliable current methods. And the low-molecular-weight species found result from incomplete synthesis of carrageenan by the alga itself, rather than from its degradation into polygenases.

Food grade carrageenan IS NOT A CARCINOGEN. If there is any gastrointestinal discomfort associated with consumption, it is fine to avoid. It's certainly not a fault. If you are ideologically against extensively processed foods because they are not "natural", that's fine. But in the interest of truth and against nutritional terrorism, the fear of developing cancer is unfounded. If, instead of carrageenan, they put in the pudding the wretched seaweed from which they get it, nobody would worry. They'd even call it a superfood! This seaweed is part of the native diet in the Philippines and Indonesia, and that is not why the incidence of cancer is higher.