Carrageenan is a food additive derived from red seaweed used to thicken and stabilize processed foods. While its degraded form, poligeenan, increases cancer risk, carrageenan does not.

Carrageenan is an additive used to thicken, emulsify (improve mixing), and preserve processed foods and drinks’ texture, taste, shelf-life, and appearance.

It comes from red seaweed (also called Irish moss). You’ll often find this ingredient in:

  • nut milks
  • meat products, such as deli meats and other processed meats
  • plant-based meat alternatives
  • yogurt
  • ice cream

According to the Food and Drug Administration (FDA), food-grade carrageenan is “generally recognized as safe” (GRAS). However, there is controversy surrounding this designation among some researchers and other experts.

Since the late 1960s, controversy has surrounded the potential health effects of carrageenan. Some research suggests that carrageenan may trigger inflammation, gastrointestinal ulcerations, and damage to the digestive system. People have petitioned for products with carrageenan to be labeled with a warning or removed entirely.

However, there is controversy surrounding these claims, and not all research suggests negative effects.

Read on to learn more about this common food additive, its potential health effects, and the controversy surrounding it.

Some researchers propose that the negative associations of carrageenan depend on its molecular structure.

Degraded carrageenan, or poligeenan, is not safe for consumption. Though both come from red seaweed, carrageenan and degraded carrageenan are different.

After being extracted from red seaweed, carrageenan is then processed with alkaline substances.

When carrageenan is processed with acid (instead of alkaline substances), it creates poligeenan, which was previously called degraded carrageenan. Poligeenan is not safe for consumption and is not a food additive.

Because it increases inflammation, researchers use poligeenan to cause inflammation in animals when conducting research on anti-inflammatory drugs.

Carrageenan is not considered carcinogenic (cancer-causing), though poligeenan is. Poligeenan is not food-grade and not “generally recognized as safe.”

Some researchers have proposed that carrageenan may degrade to poligeenan in the gut. However, a 2024 review of research notes that previous studies on excretion suggest that 98% to 100% of carrageenan is excreted without becoming significantly degraded into poligeenan.

So far, research doesn’t suggest that carrageenan is necessarily unsafe.

Carrageenan may have negative side effects.

Some people may report bloating, diarrhea, and gas when consuming it.

Digestive problems

The same 2024 review on the effects of food-grade carrageenan suggests that a person’s reaction to ingested carrageenan can depend on different conditions in their gastrointestinal tract, such as:

  • the acidity of their digestive juices
  • the integrity of their mucus membranes (which protect the organs in the digestive tract from damage)
  • if they have previous damage to their digestive system

Depending on these factors, carrageenan may:

Researchers are still investigating the relationship between carrageenan and inflammatory bowel disease (IBD), such as Crohn’s disease and ulcerative colitis.

But a 2021 review of research suggests a possible relationship between an increased amount of carrageenan in the diet and the risk of IBD relapse.

Insulin sensitivity

A 2024 clinical trial suggests there’s a relationship between insulin resistance and carrageenan. Researchers found that a diet high in carrageenan could disrupt the function of the intestinal barrier in humans, though it didn’t impact whole-body insulin sensitivity in young “metabolically healthy” male patients. However, interactions with body mass index (BMI) suggest carrageenan may have an impact on insulin sensitivity in people with a higher BMI.

The researchers suggest that people with an increased risk of type 2 diabetes consume fewer carrageenan-containing foods. However, it’s important to point out that the researchers only included male participants.

Allergic reactions

It’s possible to have a carrageenan food allergy.

A review of research from 2021 reports that people with carrageenan allergy may experience anaphylaxis, a life threatening allergic reaction.

One person who experienced digestive symptoms after having processed milk later experienced anaphylaxis after a barium enema that contained carrageenan solution.

An infant also received a diagnosis of carrageenan allergy after facial swelling following consumption of icing containing carrageenan and a positive skin prick test.

When it’s an emergency

Contact 911 or your local emergency services if you experience symptoms of anaphylaxis, which can include:

  • difficulty breathing or swallowing
  • facial swelling
  • rash
  • coughing
  • swelling in your mouth and throat

Carrageenan is a plant protein that tends to be found in processed vegan and vegetarian products. Since it is a plant, manufacturers use it to replace gelatin, which is made from animal parts.

Common sources of carrageenan

  • chocolate milk
  • cottage cheese
  • cream
  • ice cream
  • almond milk
  • dairy alternatives, such as vegan cheeses or nondairy desserts
  • coconut milk
  • creamers
  • hemp milk
  • rice milk
  • soy milk
  • deli meats
  • meat alternatives
  • salad dressings
  • canned pet foods

Carrageenan has no nutritional value, so you don’t have to worry about missing anything when you remove foods containing it.

Finding replacements for vegetarian or vegan foods without carrageenan is possible. Note that carrageenan-free milks may separate. This is natural. All you have to do is shake well before pouring. Alternatives may include:

Carrageenan is a food additive commonly found in processed foods. Many of these foods may also be high in fat and sodium.

Eating a diet that contains a lot of processed foods is associated with various health conditions, including:

You may be able to consume less carrageenan by eating fewer highly processed foods. Some ways to get started include eating more:

  • whole grains
  • beans and legumes
  • fruits and vegetables, including fresh and frozen options

Carrageenan is a food additive that’s often added to processed foods to improve their texture, taste, shelf life, and appearance. According to the FDA, it’s generally recognized as safe

The degraded form of carrageenan, poligeenan, is a known carcinogen. This type is not added to food.

Some people may still experience side effects like bloating, digestive issues, or allergic reactions from carrageenan.

If you’re worried about the side effects of carrageenan, you can remove it from your diet and see if your symptoms improve.

Carrageenan is legally required to be listed as an ingredient in a product, so it should be easy to start identifying foods to eliminate.

Talk with a doctor if you continue to experience inflammation or digestive issues after removing carrageenan. This may indicate that carrageenan isn’t responsible for your symptoms.