What Is Carrageenan and Is It Safe?

It's in everything from almond milk to baby formula, but has been linked to serious inflammation and colon cancer. Here's what experts have to say.

Photo: Getty Images/iprogressman

We're immediately skeptical of any ingredient that's hard to pronounce. Add to that a reputation for inducing inflammation and potentially causing cancer and carrageenan doesn't have a lot going for it—except that the molecule is in the majority of your favorite health foods, like protein shakes, almond milk, and cottage cheese.

But is carrageenan really as bad as it's been made out to be? Here, everything you need to know about the ingredient and whether you really do need to steer clear of it.

What is carrageenan?

Carrageenan is a carbohydrate extracted from seaweed that's used to thicken certain foods and improve how well other ingredients are incorporated (think: keeping cacao mixed into chocolate milk and smoothing out the grittiness of plant protein in a pre-packaged smoothie).

"Manufacturers use it in foods to improve the 'mouth feel' of a finished product, like making something taste creamier or smoother," explains Utah-based nutritional biochemist Shawn Talbott, Ph.D.

Is carrageenan healthy?

The ingredient isn't necessarily unhealthy, but it also doesn't add any nutritional value. While seaweed itself is quite minerally dense, commercial carrageenan is stripped of all its minerals, explains Rachele Pojednic, Ph.D., assistant professor of food science at Simmons University in Boston. Its sole purpose is to provide texture, not nutrients.

Is carrageenan dangerous?

Headlines have blasted carrageenan's connection to inflammation in the body, maybe even colon cancer. The truth: There's a little bit of foundation here, but mostly it's a lot of noise and overreaction.

The controversy started in 2001 (after carrageenan had already been incorporated into food production for a number of decades) when researchers at the University of Iowa published the first study review to call out concerns that the ingredient posed a risk for everything from abdominal bloating to more serious issues like cancer.

It all came down to one molecule, poligeenan. When carrageenan is exposed to acidic environments, it can degrade into poligeenan, which is not approved to be in food and is actually classified as a potential human carcinogen, explains Seattle-based naturopathic physician Michelle Simon, Ph.D., president of the Institute for Natural Medicine.

Fast forward nearly two decades and there turns out to be some preliminary (but conflicting) evidence that suggests human stomach acid might be enough to break carrageenan down into harmful poligeenan, plus some animal studies that show even non-degraded carrageenan can cause inflammation and bowel disorders, possibly contributing to intestinal ulcers and irritable bowel disease, explains Simon. (

The issue with all this: None of these studies confirm the molecular breakdown or subsequent effects in humans, only human cells or animals.

"Carrageenan has been used in very large doses to induce inflammation in some animal models," says Pojednic. "But, typically it's not the form of carrageenan you find in the food supply; it is poligeenan." And since there is no confirmation that your stomach acid actually turns the former into the latter, there's no proof that carrageenan actually increases inflammation in the body.

"These types of rodent studies can be used to make any ingredient look bad," says Talbott. "Any 'healthy' [or 'non-healthy'] ingredient can be shown to cause inflammation in a variety of [lab tests] since it's typically delivered in high-isolated doses, which has zero relevance to a balanced diet."

So is carrageenan safe?

This is the million dollar question. While no expert we spoke to was necessarily a fan of carrageenan, in March 2018, the European food safety authorities re-reviewed carrageenan and determined the research weighed in favor of no concern for carcinogenicity (cancer-causing), genotoxicity (DNA-harming), or prenatal development, says Simon. This is also where the FDA stands.

That being said, the European authorities also acknowledged there were unanswered questions and put a five-year deadline for more science on their approval.

The Final Word On Carrageenan

"There are still important unanswered questions that relate to the true interaction between carrageenan and humans," says Simon. "We don't yet understand how carrageenan interacts with human physicochemical properties, its impact on digestive properties, the interaction with colonic microbiome and inflammation." (

And carrageenan certainly has no health benefits. But, until we have definite research saying otherwise, the ingredient is relatively safe to consume in small quantities.

Plus, it's important to remember that the overall combination of ingredients in a product is more important than one questionable chemical, says Talbott. That is, if you have a choice between a high-protein, low-sugar drink that contains carrageenan or a sugar bomb with clean ingredients but no nutrients, the former is still probably your healthiest bet. (Or make your own carrageenan-free smoothies at home with these healthy vegetable smoothie recipes.)

That being said, there are better alternatives to thickening and emulsifying out there, says Talbott. Xanthan gum, locust bean gum, gum Arabic, guar gum, and alginate are all less risky additions that you should opt for in your health foods if you can.

Updated by
Rachael Schultz
Rachael Schultz is a health and fitness journalist and the former online news editor for Shape. She currently serves as a freelance writer and gear editor at Insider.
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