Carrageenan is generally used as either a thickener or an emulsifier (something that keeps ingredients from separating). A wide array of products contain the stuff, most notably yogurt, milk, ice cream, soy milk, salad dressings, and chocolate. The USDA allows the use of carrageenan even in organic products.
So, just how bad is this stuff? Prevention reports that a review of 45 studies examining the additive's effects on animals found that carrageenan could increase the risk of ulcerations and cancer in the stomach and colon. However, at least some of the existing research might not be applicable to the carrageenan we interact with every day. "Most of these studies looked at degraded carrageenan instead of the undegraded form, which is what is used in human food products," points out nutritionist Rania Batayneh, MPH, author of The One One One Diet.
Still, some believe it might be better to be safe than (potentially very, very) sorry — especially considering the additive's prevalence in so many of the foods we eat every day, from almond milk to pasta sauce. Nutritionist Shira Lenchewski suggests, "Some studies have linked carrageenan to GI inflammation. I advise individuals with inflammatory bowel conditions to avoid it – and often recommend experimenting with homemade almond milk recipes."
At the very least, it’s worth a second thought the next time you find yourself reaching for — well, just about anything in the grocery store.