It’s a thickener often used in dairy products or non-dairy replacements (almond milk, whipped cream, etc.). It can be difficult to digest for some people. Personally, I try to avoid it as I have other digestive issues which make me more susceptible and I don’t want to make them worse.
I have a big problem with carrageenan. Personally, I think some people are much more sensitive to its inflammatory effects than others (possibly like an allergy?).My history with this goes back more than 15 years ago when I ended up going to a prompt care for what felt like something swollen at the base of my rib cage on the left side. They could not figure out what was causing it and it eventually subsided. Then during the holidays one year I had the same symptoms with swelling in same area and happened to mention it to my sister. She said she would often get the same issue when she drank too much store bought eggnog.That got me to researching and I discovered Caragenan was the issue. My Mom, sister, a nephew and my son all have similar issues, but none of my other 4 siblings so I think it maybe genetically linked or an allergy.
They give it to lab rats to cause inflammation so they can test anti inflammatory drugs so that tells you it has some negative impacts at least on some of us. There is a professor from University of Illinois who has lobbied the FDA to remove it from the GRAS list of additives (generally regarded as safe).
It’s another one of those ingredients that got vilified based on a single piece of poorly done research. It can cause GI distress in some people, so avoid it if that’s the case. But from a general nutrition perspective, it’s completely fine.
I used to get sick and angry from certain foods. I’ll talk chocolate milk specifically. One day, I was killing some time in the grocery store cause my dad took a call, so I decided to investigate why some chocolate milk made me sick and pissed off and others didn’t. The culprit was carageenan. A lot of stuff made sense after that and I felt a lot better when I started to avoid it. I would nearly immediately be filled with rage and have diarrhea if I did have it.
Interestingly enough, once I was medicated properly for bipolar disorder, I had much less of a reaction to this additive. I think it messes with my microbiome, which in turn messes with my mood (see the brain-gut axis it’s cool shit). I still don’t have it often but can tolerate it better if I do.
There are plenty of studies of carrageenan that indicate it can be harmful to the gut (however, they are also including poligeenan which is it’s degraded form) Every person is different. If you have gut issues, are autoimmune, etc. it’s usually recommended to avoid it. It’s used as a thickner. It’s often in a lot of nut milks. Make sure you look at the ingredients to avoid, if you have to. Nutrition should be individualized, we are all different. Take a look at this study. Please keep in mind poligeenan is degraded carrageenan. Unfortunately carrageenan gets roped in to the same studies and is vilified unfairly. I personally don’t have a problem with carrageenan. Here’s some info:
https://pubmed.ncbi.nlm.nih.gov/12389870/
https://www.sciencedirect.com/science/article/abs/pii/S001562647380327X