Carrageenan, a fibrous ingredient found in a wide variety of foods, is made from red seaweed, and in its pure form is considered gluten-free.
Manufacturers use carrageenan as a thickener in such foods as ice cream, yogurt, soy milk and diet soda. It also helps to stabilize or "gell" certain foods (I've seen it listed as an ingredient in hot dogs and lunch meat, for example).
But some experts -- particularly natural foods advocates -- have raised questions about carrageenan's overall safety, especially for people with gastrointestinal disorders. They maintain the ingredient is linked to inflammation and isn't safe for anyone to eat.
What's Up With Carrageenan?
Research indicates that carrageenan may spark inflammation in the body. In fact, researchers have routinely used forms of the seaweed-derived substance to cause inflammation in mice and rats so that they then could test anti-inflammatory pharmaceuticals in those animals. However, the forms used for that purpose aren't the same as those used as food additives.
One researcher, Dr. Joanne Tobacman, associate professor at the University of Illinois College of Medicine, published a study in 2001 that linked both the forms of carrageenan used in food products and the forms used in rodent experiments to ulcers and cancer in the large intestines of rodents.
"Because of the acknowledged carcinogenic properties of degraded carrageenan in animal models and the cancer-promoting effects of undegraded carrageenan in experimental models, the widespread use of carrageenan in the Western diet should be reconsidered," Dr. Tobacman wrote.
However, others investigating carrageenan's safety — including the World Health Organization — disagreed that carrageenan, when eaten, can have a harmful effect. They note that carrageenan can cause inflammation when injected (as it generally has been in those experiments with rats and mice) but doesn't have the same effect when eaten.
Carrageenan's Bottom Line on the Gluten-Free Diet
Some natural health advocates — including some physicians — urge those with inflammatory bowel disease to steer clear of carrageenan. However, there's been absolutely no research — pro or con — into the safety of carrageenan for those who have celiac disease or non-celiac gluten sensitivity.
So should you eat products that include carrageenan or not?
Well, carrageenan should be safely gluten-free when it's included in products that are labeled "gluten-free," so gluten isn't the issue here — it's an issue of ingredient safety. Unfortunately, given the lack of research on carrageenan in gluten-related conditions, you'll need to decide for yourself, potentially in consultation with your doctor, whether or not you should consume products that include it.
More on specific ingredients and the gluten-free diet:
- Are Wheat Grass and Barley Grass Gluten-Free?
- Are Sprouted Grains Gluten-Free?
- Is Einkorn Wheat Gluten-Free?
Cohen S.M. et al. A critical review of the toxicological effects of carrageenan and processed eucheuma seaweed on the gastrointestinal tract. Critical Reviews in Toxicology. 2002 Sep;32(5):413-44.
Tobacman J.K. Review of harmful gastrointestinal effects of carrageenan in animal experiments. Environmental Health Perspectives. 2001 Oct;109(10):983-94.
World Health Organization. Evaluation of certain food additive and contaminants. World Health Organization Technical Report Series. 2011;(960):1-226, back cover.