Carrageenan—Is This Additive Safe?

Wednesday Jul 3 | BY |
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Have you checked the ingredient list on your soymilk, pudding, toothpaste, or chocolate? You may find “carrageenan,” a food additive recently tied with potential stomach tumors.

Look on the back of your ice cream, pudding, soymilk, salad dressing, infant formula, beer, or even toothpaste, and you may see the ingredient “carrageenan” listed there. A common additive derived from seaweed, it’s long been considered to be safe, but some recent studies have raised concerns that it may cause gastrointestinal ulcerations and tumors.

What’s the bottom line on this ingredient? Should you avoid it?

What is Carrageenan?

Carrageenan is a polysaccharide extracted from red seaweed (Chondrus crispus), which is commonly known as Irish moss. It’s not the same as Irish moss, however, as it’s an isolated compound with no nutritional value. (Irish moss is a dark purple edible seaweed.)

Carrageenan is used as a thickener and emulsifier to improve the texture of ice cream, soymilk, yogurt, cottage cheese, non-dairy milk, deli meats, and other foods. In non-food items like air freshener gels and toothpastes, it also helps thicken and stabilize the product, making it smoother.

This additive may be processed in one of two ways:

  1. Refined: The algae are cooked in an alkaline solution, then the solid parts are filtered out. The remaining solution contains the carrageenan, which is then concentrated, removed from the solution, and dried.
  2. Semi-refined: The algae are cooked in an alkaline solution that contains potassium hydroxide. This prevents the carrageenan from dissolving in the solution, so that when the algae are removed, what is left is carrageenan and cellulose, which is ground into a powder.

What Are the Concerns?

It started about 10 years ago, when a University of Iowa review of animal studies raised concerns about carrageenan. The results showed that the additive—particularly a “degraded” form that may be produced during food preparation and digestion—to gastrointestinal ulcerations and tumors in mice.

Degraded carrageenan is not allowed in food, but the concern is that even undegraded may cause harm, particularly if it is somehow changed during the digestive process.

In the study, the author states that in 1982, the International Agency for Research on Cancer identified “sufficient evidence for the carcinogenicity of degraded carrageenan in animals to regard it as posing a carcinogenic risk to humans.” He also speculates that the association between the additive and the health problems may be caused by contamination of the carrageenan, or by interaction with intestinal bacteria during normal digestion.

The FDA considered restricting dietary carrageenan in 1972, but that never happened, so today manufacturers are free to use it as they please—and we’re being exposed to it in a number of our everyday products.

Other Studies Show Similar Results

According to the University of California, Berkeley, several lab studies have shown that both “foodgrade” and “degraded” carrageenan can cause inflammation and increased cell death in human colon cells. Some scientists have disputed the importance of these findings, noting that animals have very different intestinal systems than humans. So far, human studies are lacking, and many scientists believe that’s what we need before we can truly evaluate the risk.

Still, others remain concerned, including Dr. Stephen Hanasuer, M.D., Chief of Gastroenterology, Hepatology and Nutrition at the University of Chicago School of Medicine, who stated: “The rising incidence and prevalence of ulcerative colitis across the globe is correlated with the increased consumption of processed foods, including products containing carrageenan.”

The well-known Dr. Weil has also added his voice to the debate, advising his readers to avoid regular consumption of foods containing carrageenan because of Dr. Tobacman’s research, and increases the severity of that warning for people with inflammatory bowel disease.

A Petition for Change

In 2008, Dr. Joanne Tobacman, the author of the first study mentioned here, filed a citizen petition with the FDA, presenting scientific studies linking carrageenan to gastrointestinal inflammation and disease, including cancer. Years later, in 2012, the FDA rejected the petition.

“It has been reviewed repeatedly by FDA scientists and other international organizations,” said Michael Adams, deputy director of the FDA’s Office of Food Additive Safety, “and in the judgment of those experts, there hasn’t been a problem.”

Some researchers, however, continue to disagree. “Carrageenan has a unique chemical structure,” said Dr. Pradeep Dudeja, Professor of Physiology in Medicine at the University of Illinois-Chicago, who has co-authored nine studies on the additive, “and research has shown that this chemical structure may trigger an innate immune response in the body. The immune response leads to inflammation, which is a serious public health concern since chronic, low-grade inflammation is a well-known precursor to more serious diseases, including diabetes and cancer.”

In 2007, the Joint FAO/WHO Expert Committee on Food Additives advised against the use of carrageenan in infant formula—it is now banned in infant formula in Europe.

Symptoms Occurring Today?

Some consumers say that they’ve noticed gastrointestinal upset after consuming carrageenan, and have found relief upon eliminating it from their diet. The Chicago Tribune reported on one such consumer, Sara Baker, a career services coordinator from Bloomington, Illinois. A victim of ulcerative colitis, she would experience flare-ups now and then, and finally linked many of them to her consumption of carrageenan—once, in her hot cocoa.

“I went back and looked at the package, and there it was: carrageenan,” she says. “It took awhile to learn just how many things it’s in, but now that I know, I can avoid it, and I no longer have the problems.”

To help further clarify the risks, scientists at the University of Illinois at Chicago and University of Chicago are conducting a controlled clinical trial—on humans. “I believe it’s worth investigating and doing the science to find out,” said Dr. Stephen Hanauer, a medical professor and chief of gastroenterology and nutrition at University of Chicago Medicine.

On March 15, 2013, the Cornucopia Institute—which engages in educational activities supporting sustainable and organic agriculture and has released a report on carrageenan—sent a letter to the FDA Commissioner, Dr. Margaret Hamburg, requesting the agency reconsider their decision to deny the citizen petition that requested the removal of the additive from the FDA’s list of approved food additives.

How to Reduce Your Exposure

The FDA continues to maintain that carrageenan is safe, so as this point, it’s up to individuals to make their own choices. If you’re concerned that you may be affected, you can avoid it by reading labels, and refusing to consume those products that list it. Safer alternatives, according to the University of California, Berkeley, include guar, locust bean, and xanthan gum.

Some brands are already working to remove carrageenan from their products, including Stonyfield Farm (which makes organic yogurt) and Eden Foods. Tofu Shop Specialty Foods offers chocolate soymilk without carrageenan.

You can find a shopping guide for avoiding foods with carrageenan, on the Cornucopia Institute web page.

What do you think of carrageenan? Will you avoid it in the future?

* * *

“Ask the Experts,” University of California, Berkeley Wellness Letter, March 2013.

JK Tobacman, “Review of harmful gastrointestinal effects of carrageenan in animal experiments,” Environ Health Perspect 2001 October; 109(10):983-994,

Lynn Buske, “New Report: Food Additive (Carrageenan) Suspected in GI Disease/Tumors—FDA asked to pull from Market,” The Cornucopia Institute, March 18, 2013,

Andrew Weil, “Is Carrageenan Safe?” Ask Dr. Weil, October 1, 2012,

Monica Eng, “Doubts surface about safety of common food additive, carrageenan,” The Chicago Tribune, March 18, 2013,

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho.


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  1. Elisabeth says:

    carrageenan and all other gums give me a migraine headache. even the “less then 1% guar gum” in the coconut milk!

  2. Debbie says:


    Q. What is Carrageenan??

    A. Carrageenan is a naturally-occurring seaweed extract. It is widely used in foods and non-foods to improve texture and stability. Common uses include meat and poultry, dairy products, canned pet food, cosmetics and toothpaste.
    Q. Why the controversy?
    A. Self-appointed consumer watchdogs have produced numerous web pages filled with words condemning carrageenan as an unsafe food additive for human consumption. However, in 70+ years of carrageenan being used in processed foods, not a single substantiated claim of an acute or chronic disease has been reported as arising from carrageenan consumption. On a more science-based footing, food regulatory agencies in the US, the EU, and in the UN’s Food and Agriculture Organization/World Health Organization (FAO/WHO) repeatedly review and continue to approve carrageenan as a safe food additive.
    Q. What has led up to this misrepresentation of the safety of an important food stabilizer, gelling agent and thickener?
    A. It clearly has to be attributed to the research of Dr. Joanne Tobacman, an Associate Prof at the University of Illinois in Chicago. She and a group of molecular biologists have accused carrageenan of being a potential inflammatory agent as a conclusion from laboratory experiments with cells of the digestive tract. It requires a lot of unproven assumptions to even suggest that consumption of carrageenan in the human diet causes inflammatory diseases of the digestive tract. The objectivity of the Chicago research is also flawed by the fact that Dr Tobacman has tried to have carrageenan declared an unsafe food additive on weak technical arguments that she broadcast widely a decade before the University of Chicago research began.

    Q. What brings poligeenan into a discussion of carrageenan?
    A. Poligeenan (“degraded carrageenan” in pre-1988 scientific and regulatory publications) is a possible carcinogen to humans; carrageenan is not. The only relationship between carrageenan and poligeenan is that the former is the starting material to make the latter. Poligeenan is not a component of carrageenan and cannot be produced in the digestive tract from carrageenan-containing foods.
    Q. What are the differences between poligeenan and carrageenan?
    A. The production process for poligeenan requires treating carrageenan with strong acid at high temp (about that of boiling water) for 6 hours or more. These severe processing conditions convert the long chains of carrageenan to much shorter ones: ten to one hundred times shorter. In scientific terms the molecular weight of poligeenan is 10,000 to 20,000; whereas that of carrageenan is 200,000 to 800,000. Concern has been raised about the amount of material in carrageenan with molecular weight less than 50,000. The actual amount (well under 1%) cannot even be detected accurately with current technology. Certainly it presents no threat to human health.
    Q. What is the importance of these molecular weight differences?
    A. Poligeenan contains a fraction of material low enough in molecular weight that it can penetrate the walls of the digestive tract and enter the blood stream. The molecular weight of carrageenan is high enough that this penetration is impossible. Animal feeding studies starting in the 1960s have demonstrated that once the low molecular weight fraction of poligeenan enters the blood stream in large enough amounts, pre-cancerous lesions begin to form. These lesions are not observed in animals fed with a food containing carrageenan.

    Q. Does carrageenan get absorbed in the digestive track?
    A. Carrageenan passes through the digestive system intact, much like food fiber. In fact, carrageenan is a combination of soluble and insoluble nutritional fiber, though its use level in foods is so low as not to be a significant source of fiber in the diet.
    Carrageenan has been proven completely safe for consumption. Poligeenan is not a component of carrageenan.
    Closing Remarks
    The consumer watchdogs with their blogs and websites would do far more service to consumers by researching their sources and present only what can be substantiated by good science. Unfortunately we are in an era of media frenzy that rewards controversy.
    Additional information available:
    On June 11th, 2008, Dr. Joanne Tobacman petitioned the FDA to revoke the current regulations permitting use of carrageenan as a food additive.
    On June 11th, 2012 the FDA denied her petition, categorically addressing and ultimately dismissing all of her claims; their rebuttal supported by the results of several in-depth, scientific studies.
    If you would like to read the full petition and FDA response, they can be accessed at!searchResults;rpp=25;po=0;s=FDA-2008-P-0347

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