R.C., AGE 25, felt lethargic and bloated. When her skin erupted in a red, itchy rash, she headed for the ER where she was told she could be experiencing a kind of anaphylactic shock. The most likely cause: the food additive almost no one has heard of, although it’s found in some of the healthiest vegan and vegetarian foods.
Carrageenan is used as a thickener or emulsifier—a stabilizer, to keep ingredients from separating unappealingly— in processed foods like some ice creams, cheeses, meats, high-protein beverages and diet soft drinks, as well as in some toothpastes.
Among healthy brands, it is found in Stonyfield products, such as some Greek yogurts and organic heavy whipping cream; and in Applegate Naturals products like turkey breast. But it is most prevalent in vegetable-based milk substitutes, including some soy and almond milk—notably Almond Dream and SO Almond Plus —which R.C. drank often, and in some used by Starbucks.
Extracted from red seaweed, carrageenan is a type of Chondrus crispus, also called Irish moss and used in Ireland to make a panna cotta-like jelly. Researchers studying carrageenan since the 1960s have seen no conclusive evidence of harm to humans but have found links in lab animals and human cells to gastrointestinal disease, including ulcerative colitis, intestinal lesions and colon cancer.
“As with magnesium stearate and soy lecithin, carrageenan has been frequently portrayed as significantly more harmful than is supported by available evidence,” according to Berkeley, California, functional medicine practitioner Chris Kresser, author of The Paleo Cure. But Kresser considers carrageenan slightly “more concerning than the other two “because of its association with gut issues.”
“There is evidence that [carrageenans] can be harmful, especially if consumed regularly,” said Kresser: “Many people report reacting negatively with symptoms like digestive troubles, skin rashes and other health problems.”
Personally, Kresser “adheres to the ‘precautionary principle’ for anything I eat,” staying away from foods that have not been proven safe and have questionable adverse effects.” And he recommends “avoiding carrageenan especially [for those with] a history of digestive problems.”
In April 2018, the USDA renewed carrageenan on the National List of allowable food products—a decision made on the grounds that “carrageenan continues to be necessary for handling agricultural products because of the unavailability of wholly natural substitutes,” according to NPR.
On the other hand, in 2016, the National Organic Standards Board voted to drop carrageenan from the list of approved organic ingredients based on evidence that it could be replaced by other ingredients. In the EU, carrageenan is banned for use in infant formula for “precautionary reasons,” but is permitted in other food items.
Carrageenan “activates an immune response that dials up inflammation” in lab animals and cultures of human cells, explains Joanne Tobacman, associate professor of clinical medicine at the University of Illinois, Chicago. “Although derived from a natural source, it appears to be particularly destructive to the digestive system.”
In fact, drug investigators have used carrageenan to cause inflammation when testing anti-inflammatory properties of new drugs, Tobacman points out. Also, mice exposed to carrageenans have developed glucose intolerance and impaired insulin action, possible precursors of diabetes. (The plural “carrageenans” refers to different forms of the additive.)
Carrageenan triggers “an immune response similar to that [caused by] pathogens like Salmonella…inflammation which can lead to ulcerations and bleeding,” said Tobacman. Her 2008 petition to the FDA cited decades of peer-reviewed research—to which the FDA responded with a letter of denial.
The FDA cited as “the gold standard” a 2006 rat study, despite its funding by a carrageenan manufacturer. Challenging the FDA denial, the organic industry watchdog group Cornucopia Institute asked why the FDA didn’t consider more recent studies.
Cornucopia Institute publishes a “shopping guide to avoiding organic foods with carrageenans,” although sufferers like R.C. have found that the “bad” list omits many carrageenan-containing almond milks.
Vegetable-based milk substitutes are especially popular among those on Paleo diets and for those seeking relief from GERD (gastro-esophageal reflux disorder), but for the latter group, if symptoms persist, carrageenans may be another culprit to consider.
Every Tuesday in this space Mary Carpenter reports on well-being, taking on topics like living longer, the dangers of homeopathy and psychedelic therapy.