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What's The Deal With Carrageenan? Is It Bad For Your Gut Or Fine?

Sara McGlothlin
December 19, 2018
Sara McGlothlin
Certified Holistic Nutritionist
By Sara McGlothlin
Certified Holistic Nutritionist
Sara McGlothlin is a certified holistic nutrition and wellness coach based in Richmond, Virginia. She graduated from the University of Virginia with a B.A. in economics, and received her master's in elementary education from Mary Baldwin College.
Image by Milles Studio / Stocksy
December 19, 2018

The first time I ever heard of carrageenan was immediately following my shift to a dairy-free lifestyle. Organic almond and coconut milks quickly became new kitchen staples, and many brands that I considered super healthy featured the ingredient on their label. But what is carrageenan? Is it a health friend or foe?

What is carrageenan?

Derived from red seaweed, carrageenan's unique chemical structure1 makes it an effective emulsifier, binder, and thickening agent, and therefore it is widely used in both the food and pharmaceutical industries2. It can be found in many milk substitutes, coffee creamers, coconut waters, and yogurts and is even hiding in baby formula, deli meat, supplements, and toothpaste.

Where is carrageenan found—and why?

While carrageenan was first introduced to our country's food scene in the 1930s3, the substance has been used all over the world for centuries. It is said that inhabitants of coastal Ireland harvested Irish moss after discovering that boiling the seaweed released a gel-like derivative that thickened milk, turning it into a creamy pudding. Carrageenan has also historically been used medicinally as a laxative and to treat peptic ulcers3. With the rise of processed foods—and more specifically no-fat, low-fat, and dairy-free foods—carrageenan became an ingredient to thicken, stabilize, and texturize. It offers no nutritional value or flavor, yet food manufacturers have found it to be an effective (and inexpensive) way to "improve" a product's formulation4:

Carrageenan provides that "fatty" texture that would otherwise be missing from many fat-free and low-fat food items. It's often used in beverages that tend to separate and therefore would need to be shaken or stirred after they hit the shelves. Examples include chocolate milk, nutritional shakes, and dairy-free alternatives like almond and coconut milks.

It can be found in prepared and precooked poultry and deli meats to preserve juiciness and maintain tenderness. Many prepackaged pizza crusts contain carrageenan for that "doughy" feel. It's found in liquid infant formula as a binder and thickener.

OK, so—is carrageenan safe?

There are two types of carrageenan: degraded, also known as poligeenan, and un-degraded, or "food grade." The difference5 is in how the seaweed is prepared. Degraded carrageenan is processed in an acidic solution and has a lower molecular weight3, while its un-degraded counterpart undergoes an alkaline procedure, resulting in what food manufacturers argue to be both a natural and safe ingredient.

Since the 1960s, studies have shown6 that degraded carrageenan is not only damaging to the digestive system7 but is highly inflammatory and carcinogenic8 as well. While degraded is not allowed in food, scientists and health advocates have raised concern for dietary-approved carrageenan for decades. The controversy has many layers. Whereas degraded and un-degraded differ in molecular weight, sometimes it isn't by much3Results of industry tests showed that every sample of un-degraded carrageenan was contaminated with poligeenan, some containing up to 25 percent. Furthermore, research reveals9 that as the additive passes through the normal conditions of the gastrointestinal tract, it is exposed to an acidic environment that degrades its quality and leads to carcinogenicity. Back in 197210, the U.S. Food and Drug Administration encouraged restricting the use of dietary carrageenan, but the ban was never upheld.

The report quotes consumers who were suffering from a variety of undiagnosed gastrointestinal symptoms: bloating, abdominal cramps, diarrhea, and nausea, to name a few. For years the source of their digestive distress went unexplained. Upon eliminating the ingredient from their diet, they experienced relief. This is likely tied to carrageenan's inflammatory effect in the colon and intestines11. Sometimes, low-grade inflammation produces certain signs and symptoms, but without knowing what to look out for, it can go undetected. Evidence clearly supports carrageenan's pro-inflammatory nature12, and in fact, researchers in the pharmacology industry have used carrageenan for decades to induce inflammation13 in laboratory animals to test the effectiveness of anti-inflammatory drugs14. Lastly, carrageenan has also been characterized as an immunosuppressant15.

What are the side effects of carrageenan?

For the past few decades, numerous animal studies9 have linked food-grade carrageenan to some pretty serious (and scary) health issues. In 2013, the Cornucopia Institute published this report, and it didn't paint a pretty picture. Here are some of the science-supported ways this ingredient could harm your health:

1. Carrageenan could contribute to inflammatory bowel disease.

A major reason doctors, scientists, and health advocates caution against carrageenan is due to its inflammatory effects in the digestive tract3. Research has connected carrageenan to large bowel ulcerations16, ulcerative colitis6, and other forms of irritable bowel disease3. These documented results provide strong claims that are difficult to deny. Additionally, this study11 speculates that carrageenan could trigger Crohn's and colitis in people who are genetically predisposed to the disease. 

2. Carrageenan has been linked to cancer.

Many studies show that both degraded and un-degraded9 carrageenan are carcinogenic. It promotes the growth of intestinal tumors17 and has been linked to colon17, colorectal, and liver cancers. This study18 specifies that carrageenan causes colon abnormalities, which are a precursor to polyps.

3. Carrageenan can mess with blood sugar and hormone balance.

Studies show that consuming carrageenan significantly impairs blood sugar tolerance19 by increasing insulin resistance20 and inflammation associated with diabetes19. This finding also has implications for weight management, as insulin plays a key role. Insulin is our storage hormone, and making sure we remain insulin sensitive is crucial not only for weight but overall hormonal balance as well. 

Should you completely avoid carrageenan?

All of that said, carrageenan is also currently on the FDA approved list, which some point to as a reason that it's healthy.

The food manufacturers who use carrageenan in their products assert that the findings are animal-specific21 and therefore not applicable to human health. This study22 even concludes that the way carrageenan is currently consumed is safe for both human adults and children. Furthermore, some studies specify that carrageenan is safe in small amounts5 and that there is a significant difference between the servings found in food and the doses used in research5.

Many questions remain23 and more evidence is needed, but there are more human-based studies11 are coming forward. Bottom line? You need to listen to your own intuition and do what you feel is right for your body and your health.

If you want to avoid carrageenan, what's the best way to do so?

All of Califia's products, including a huge variety of nut milks and creamers, are 100% carrageenan free, and So Delicious's organic nut milks have some of the cleanest, carrageenan-free ingredient lists around. Stonyfield listened to consumers and removed it from their products; WhiteWave, the parent company of Horizon and Silk milks, also removed the ingredient from their beverages, citing consumer interest as well. However, it still can be found other brands, so it's a good one to be aware of.

Reading ingredients in order to stay informed is always a good idea, or check out this shopping list to learn more about the brands that are carrageenan-free. Also be aware that as the backlash against carrageenan continues, food manufacturers might disguise the ingredient under another name. For example, Irish moss is alternatively used, which I have to say, sounds natural enough at first glance!

When it comes to your dairy-free milk substitutes specifically, you can always try homemade. Real nut milk has minimal ingredients (ideally just nuts and water), and I promise it doesn't take long.

Homemade Carrageenan-Free Almond Milk


  • 1 cup raw almonds, soaked at least 4 hours, then drained
  • 4 cups filtered water


  1. Place nuts and water in a high-speed blender and process for about 2 minutes.
  2. Strain through a nut milk bag or cheesecloth, and transfer to an airtight container. Store in the fridge. Enjoy for up to 5 days.
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Sara McGlothlin author page.
Sara McGlothlin
Certified Holistic Nutritionist

Sara McGlothlin is a certified holistic nutrition and wellness coach based in Richmond, Virginia. She graduated from the University of Virginia with a B.A. in economics, and received her master's in elementary education from Mary Baldwin College. Her practice is inspired by her passion for educating others on how to live healthier lives. McGlothlin primarily focuses on areas such as weight loss, emotional eating, food intolerances, digestive issues, and increasing feelings of energy and overall well-being. She is also an instructor at barReVA, a local barre studio in Richmond.