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Harmful or Harmless: Carrageenan

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carrageenan, carrageenan side effects

Carrageenan, a heavily discussed additive in the world of alternative health, is an indigestible polysaccharide that is extracted from red algae, and is most commonly used in food as a thickener or stabilizer. Carrageenan-containing seaweeds have been used for centuries in food preparations for their gelling properties, but the refined, isolated carrageenan found in modern processed foods has raised concerns in the health-conscious online community. (1)

Carrageenan is especially common in non-dairy milks such as almond milk and coconut milk, which means that some people who transition to a Paleo diet might actually be increasing their exposure if they use these products. I discussed carrageenan on a recent podcast, but today I want to give you a more detailed summary of the evidence.

Hold the almond milk… is carrageenan affecting your health?

There are a few distinct types of carrageenan that differ in their chemical properties, but the most important distinction is between degraded carrageenan and undegraded carrageenan. From a chemical standpoint, the difference between these two types is in their molecular weight. From a practical standpoint, undegraded carrageenan is approved for use in food products, while degraded carrageenan is not. (2) Although both substances are often referred to as ‘carrageenan,’ they have very different chemical properties and should really be treated as separate compounds. Degraded carrageenan is also called ‘poligeenan,’ which is how I will refer to it in the rest of this article to avoid any confusion.

Animal Studies

Most of the carrageenan hysteria stems from animal studies that implicate carrageenan in the formation of ulcerations and cancerous lesions in the colon. A thorough review of the approximately 45 available animal studies on carrageenan was published in 2001, and at first glance, these studies seem alarming. However, it turns out that the majority of these animal experiments used poligeenan instead of carrageenan, and as I mentioned before, these are two separate compounds with different effects. Poligeenan is significantly more detrimental to the health of lab animals than carrageenan, so the lack of a clear designation between them has given carrageenan a worse reputation than it deserves.

One important difference is that while poligeenan can cause cancer on its own when given in high enough concentrations, undegraded carrageenan has only ever been shown to accelerate cancer formation when administered with a known carcinogen. (3) In other words, food-grade carrageenan has not been shown to cause cancer in animal models. That doesn’t necessarily mean carrageenan is in the clear when it comes to cancer, but contrary to popular belief, it is not a known carcinogen.

Additionally, poligeenan produces more severe ulceration and inflammation than carrageenan, and at lower concentrations. As an example, a study on rhesus monkeys using poligeenan at 0.5-2% resulted in diarrhea, hemorrhage, and ulcerations, while carrageenan at 1-3% resulted in no colonic changes. (4) (For reference, the concentration of carrageenan in processed food is usually between 0.01% and 1%.) (5)

However, carrageenan has produced intestinal damage in some animal studies. Observed effects in rats include epithelial cell loss, increased intestinal permeability, and diarrhea. (6) In guinea pigs, carrageenan at a 5% concentration in the diet caused ulcers in the colon, although a similar concentration in the diets of rats and hamsters resulted in no difference from controls. (7) In pigs, concentrations of carrageenan between .05 and .5% administered for 83 days resulted in abnormalities in the intestinal lining, but no ulcerations or tumors. (8) Still, a more recent rat study found no ulcerations or lesions in the colon after 90 days of carrageenan administration. (9) These studies suggest that the effects of carrageenan are highly species-dependent, which makes it more difficult to extrapolate these results to humans.

There are a few other important considerations when determining how applicable these results are to humans. Many of these experiments administered the carrageenan through the animals’ drinking water as opposed to their food, which tends to increase the severity of the resulting symptoms. Because carrageenan interacts with protein molecules, consuming it as part of a solid food is much less harmful than consuming it in water. Also, although many of the concentrations administered are comparable to concentrations found in processed foods, many experiments were conducted at concentrations much higher than humans would ever encounter on a normal diet. Remember, these studies are looking at carrageenan as a percentage of the entire diet, not just less than 1% of a small portion of the total diet, as is the case when using milk replacement products.

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Human Studies

Experimental evidence on the effects of carrageenan in humans is extremely limited, for obvious ethical reasons. However, a few in vitro experiments have been conducted on isolated human intestinal cells.

One study found that in intestinal epithelial tissue, carrageenan exposure increased the expression of two pro-inflammatory transcription factors. (10) This reaction appears to be protective of the intestinal tight junctions, because suppression of either of the inflammatory factors resulted in increased permeability of the isolated epithelial tissue. Unfortunately, it’s unclear whether they used food-grade carrageenan rather than poligeenan in this experiment.

Two similar studies that did use food-grade carrageenan also found that isolated intestinal epithelial tissue responded to carrageenan by up regulating inflammation. (11, 12) Another study on human intestinal epithelium found that undegraded carrageenan reduced the activity of many sulfatase enzymes, with potential negative ramifications for the function and vitality of the cell. (13)

Finally, another study found that exposing human intestinal epithelial cells to undegraded carrageenan in concentrations lower than what would be found in a typical diet caused increased cell death, reduced cell proliferation, and cell cycle arrest. (14)

These studies provide some support for the generalization of the animal studies to humans, implicating carrageenan in the potential for intestinal inflammation. However, it’s important to remember that not only were these studies in vitro (aka not in the human body), they also didn’t administer the carrageenan with any food, so the effects observed may differ significantly from what actually occurs when humans ingest carrageenan in a real-world setting.

Exposure to Poligeenan

Because poligeenan can be produced from carrageenan, many researchers and laypeople have expressed concern that we might be exposed to poligeenan through contamination of the food supply. However, the most recent sources indicate that the poligeenan contamination level of food-grade carrageenan is less than 5%. (15)

Another encouraging data point in this situation is that while carrageenan is an extremely effective thickener and emulsifier at concentrations as low as .01%, poligeenan has no functional effect in food even at concentrations up to 10%. (16) Specific chemical processing is necessary for carrageenan to be degraded to poligeenan, and because poligeenan is of no use in the food industry, it seems unlikely that poligeenan would show up in appreciable quantities in processed foods.

Another concern is whether small percentages of ingested carrageenan are degraded to poligeenan in the digestive tract after consumption, either because of the acidic environment or because of intestinal bacteria. Some experimental evidence indicates that as much as 10-20% of carrageenan could be degraded to poligeenan during digestion, while other researchers (not surprisingly funded by the carrageenan industry) assert that carrageenan is stable throughout digestion. (17, 18) Regardless, the significant differences between poligeenan and carrageenan as evidenced by the reactions of lab animals make it pretty clear that even if some degradation does take place, carrageenan still doesn’t have the potential for harm that poligeenan does.

Conclusion

As with magnesium stearate and soy lecithin, carrageenan has been frequently portrayed as significantly more harmful than is supported by available evidence. Contrary to popular belief, it’s not a known carcinogen, and although some studies implicate carrageenan in ulceration and inflammation, some show no adverse effects.

However, I do still think caution is warranted. If I had to rank additives, I’d say carrageenan is a bit more concerning than the other two additives we’ve discussed so far because of its association with gut issues. Remember, in cases involving modern ingredients, the burden of proof should be on manufacturers to prove that they’re safe, rather than on consumers to prove that they’re harmful. Because the evidence isn’t conclusive either way, I recommend avoiding carrageenan, especially if you have a history of digestive problems.

Personally, I adhere to the “precautionary principle” for anything I eat; in other words, in the absence of proven safety, I choose to avoid foods that have questionable adverse effects. Carrageenan fits this description, as there’s still some doubt about its safety and no evidence has convinced me that there isn’t a potential for harm if consumed regularly.

Occasional exposure is likely nothing to worry about, but for most people reading this, avoiding carrageenan is probably as simple as making your own nut milk or coconut milk, so I would encourage you to give that a shot. Also, if you follow the links to those two posts, some commenters have shared brands of almond and coconut milk that don’t contain carrageenan (although watch out for other additives that may be present).

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427 Comments

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  1. Is this carrageenan the same as carraigin (irish)? I am from Galway, west of Ireland. We harvest and eat this seaweed for health benefits. Usually late summer when the tide is out. We gather it from the rocks (carraig) and dry it in the sun. We add it to milk and make a jelly dessert out of it or warm milk drink. It is used to prevent the cold, flu. I never have known anyone who takes it at home to complain about stomach issues as it is generally taken to prevent illness!

    • Antoinette, natural “red marine algae” is supposed to have anti-viral properties, but carrageenan in a processed “isolate” form is the kind that has dangerous properties for some of us and is of questionable safety perhaps for others.

  2. I like Aroy-D as a brand for coconut milk. No additives or preservatives listed on the ingredients label, just coconut and water. An internet search for hidden ingredients did not turn up anything.

  3. Try Aroy-D brand coconut milk. I buy it from amazon and it is 100% pure and comes in a BPA free package. It is delicious!

    • i also like Aroy-D. i get it @ a local asian market. (also cheaper) most Thai brands do not have other stuff (emulsifier? thickeners?) so one has to shake it well.

      don’t know why American brands add so much other stuff to coconut milk.
      maybe the makers think Americans are too lazy to “shake” it. XD

    • Jen L, Aroy-D Coconut Milk costs $6.99 for 13.5 oz on amazon.com, which totals $66 a gallon. Too pricey! : D

      • Yes, Aroy-D is pricey, but I have been able to adjust my food budget to buy this product because I feel it is so worth it. We use it in our coffee/tea, in recipes, smoothies, over berries and occasionally with cereal. We do not typically drink it by the glass. According to my calculations, it costs about $30 per gallon, which is quite pricey, but less than half of what you suggested. It has a long shelf life and arrives at my doorstep within 24 hours and with free shipping.

        • Jen,

          1 If you do the math $6.99 for 13.5 oz
          adds up to $66 a gallon on amazon.com, which is where you buy it from.

          2 It doesn’t have the USDA Organic seal.

          3 It doesn’t have the Non-GMO Project Verified seal.

          4. It doesn’t have the Fair Trade Certified seal.

  4. Can you give opinion on how carageenan in a daily supplement (the capsule) might rank in comparison to daily food intake via milk sub? Would the intake be considerably small, if just used to create the gelcap….or would it be concern because it’s not with food, and it’s daily. My “gut” is to avoid it in supplements, but trying to tease out the grey-zone of if it’s just a little concern or a big one. THANK YOU!

  5. Great article. It took me a long time to figure out that the carageenan was causing me severe gastro distress. Some weeks I would feel great; other weeks, very sick. I read an article about carageenan and realized that Blue Diamond almond milk has it and Silk almond milk does not. Once I committed to Silk, I’ve felt great.

    Carageenan can be in so many products. I bought a rotisserie chicken from Costco and discovered once I got home (and put my reading glasses on) that it was one of the listed ingredients. Now, I read every label very carefully.

  6. Whole Foods Private Label Brand (365) Organic Almond milk does not have Carageenan. It has a few other items.

    Organic almondmilk (filtered water, organic almonds), tricalcium phosphate, sea salt, xanthan gum, potassium citrate, sunflower lecithin, vitamin a palmitate, ergocalciferol (vitamin d2), dl-alpha tocopherol acetate (vitamin e).

  7. Chris,
    Thanks for a fine article. My understanding used to be that carrageenan comes from Irish Moss, which is one of my favorite Paleo thickeners. What is the relationship between carrageenan and Irish Moss??
    thanks again! Jane Barthelemy from janeshealthykitchen.com.

    • Carraig is the Irish word for rock. Carraigin is another irish word meaning small rock. Usually you find this seaweed growing on the small rocks along the west coast of Ireland. We gather it and harvest it late summer when the tide is out. We dry it in the sun and add it to milk mostly to make a jelly like dessert. Carraigin is an Irish Seaweed, red in color. I think Carrageenan might be related.

    • I think Irish moss is what Chris is referring to when he says that “carrageenan-containing seaweeds have been used for centuries in food preparations for their gelling properties.” From what I understand, carrageenan used to be derived solely from Irish moss, but is now extracted from many different types of seaweed.

      I think this is probably one of those circumstances where the whole food is harmless or even beneficial, but the isolated, processed extract (carrageenan) can be harmful.

  8. I’m wondering about D-Alpha-Tocopherol (natural Vit E) Chris, any concerns with this? Or Calcium Carbonate?

  9. We’ve found that Carageenan causes our daughter’s to flare up (Dyes definitely cause). She drank Silk with no Carageenan and the rash was mostly clear. Then they got worse than ever before…very frustrating and finally figured out that the only change was from Silk to Almond Breeze. Removed her from it and the intensity cleared up.

    I’m convinced Carageenan is very inflammatory because the flare up occurs if she gets into certain ice creams or frozen yogurt containing Carageenan. Stuff is as bad as food dyes.

  10. I know that consuming carageenan causes me great amounts of intestinal distress at this pint. I had eliminated it during a Whole30, and upon reintroduction, it was very, very bad for me. So I no longer consume it whenever possible.

  11. Most brands of heavy whipping cream also contain carrageenan, even most of the brands labeled “organic”. Among those organic heavy cream brands that DO NOT have it on their labels are Clover, Trader Joe’s, and Straus.

    • Organic Valley has a version of it’s heavy cream that is free of any thickeners. It is pasturised, not ultrapasturised, so it’s shelf life is shorter (take it home on ice in a cooler), but both the taste and the mouthfeel are infinitely better than the tarted-up stuff.

      You might have to befriend your grocer and keep asking to get it.

    • I just discovered that the Pasteurized heavy cream from Trader Joe’s in the plastic container DOES have carageenan! I don’t know if the one in the carton has it or not, but it is ultra-pasteurized and from what I have read, Ultra-pasteurized dairy products contain free glutamates. I am very disappointed and am sending a comment to Trader Joe’s about this.

  12. I personally became ill from consuming plant-based milks (almond, hemp, coconut, etc.) with carrageenan. It took several months to make the connection to it and my recurring gastroenteritis. Now even a small dose can cause an upset. I have made my own milks, but I find the pre-packaged kinds more convenient. My daughter has allergies and it’s hard to find milk that meets our needs: dairy/soy/nut-free, organic, unsweetened, and carrageenan-free. Right now we’re trying quinoa milk.

    • I have tried oat, hemp, and homemade pumpkin seed milk and they are all good dairy/soy/nut-free alternatives.

    • Try Organic grass fed raw cows milk. My husband has had an allergy to all nuts, peanuts being the worst, since he was a teen. He would get sores on his head that would hurt for days, nothing life threatening though. Three months after we started drinking raw organic grass fed cows milk, he noticed that he wasn’t getting any sores after eating something made in the same facility where peanuts are used. Even that would bother him. We’ve been drinking it for almost a year now. I also cream the cream and make my own butter. I also read that people that are lactose intolerant can drink raw milk with no problems.

      • Yes, there is a theory that modern processing milks damages the milk in several ways. One, pasteurization kills the natural lactase that exists that assists with lactose processing. Also, that through homogenization, essential fat molecules are broken down in such a way that the body no longer uses them properly. However, if you do go with raw milk, be sure the facility is regularly tested, or you could be exposing yourself to dangerous bacteria.

        It seems possible that the whole fats he is now drinking in the raw milk, along with several probably unpasteurized enzymes, may be assisting in his body’s ability to deal with the nut proteins, or providing some sort of protective action. Yay!

  13. For us dairy consumers, be on notice that many ice creams and gelatos contain carrageenan. My father was in the commercial dairy business and he hated it when carrageenan was added to ice cream. I don’t eat anything with this additive.

    • Ice cream, heavy/whipping cream, buttermilk, chocolate milk. many low-fat yogurts, even some fruit juices. Kalona Supernatural dairy is all carrageenan free. Three Twins ice cream and Alden’s ice cream are organic and carrageenan free.

  14. Califa brand almond milk contains no additives. The unsweetened plain variety contains only almonds and filtered water.

    • I’m sorry, but that’s not true: http://www.califiafarms.com/products/unsweetened/

      I only know this because I occasionally buy that brand. It tastes great but it’s definitely not additive free…

      Contains Less Than 2% Of The Following: Vitamin/ Mineral Blend (Calcium Carbonate, Vitamin A, Vitamin E, Vitamin D2, Vitamin B12, Vitamin B2, Zinc), Gellan Gum, Carrageenan, Potassium Citrate, Sunflower Lecithin, Natural Flavors, Sea Salt.

      • Yes! They separate the top lines from the bottom lines, so you stop reading and don’t notice the other additives.

        For me, I think the synthetic folic acid and vitamin D2 in all these nut milks is more concerning than the carrageenan. Very few nut milks are not fortified, and those that are have carrageenan.

      • EXACTLY! AND NOTE that they have separated the paragraph “Contains less than… ” by a blank area just below the main ingredients list, so most people QUIT READING before they get to it! That strikes me as being a bit sleazy…

    • I thought the same thing, but the ingredient label looks like this:

      Ingredients: Almondmilk (Filtered Water, Almonds)

      Contain Less Than 2% of the Following: Calcium Carbonate, Gellan Gum, Carrageenan, Potassium Citrate, Natural Flavors, Sea Salt

      That space between the two is what got me also. I bought it and when I got home my mom read the ingredients and pointed out that there is carrageenan in it.

  15. I have replaced carageenan-containing lunchmeat by Applegate with carageenan-free Organic Prairie lunchmeat. Seeing as very few people test well on an SIgA test, indicating widespread incidence of compromised gut, it seemed like a good way to go for the times when my family needs to grab something quick to eat.

    • For those that have Kroger/Payless grocery stores, their “Simple truth” brand of deli meats are carrageenan free, and are labeled so prominently on the package.

  16. I drink almond milk and recently switched to the unsweetened original Silk Pure Almond. No carrageenan here.

  17. Silk unsweetened Almond Milk as well as TJ’s brand of unsweetened almond milk do not have carrageenan…

    • Wholefoods brand Almond milk Unsweetened also is carrageenan free. I usually drink the Silk Unsweetened Almond milk when I buy my almond milk. It does contain Locust Bean Gum, Sunflower Lecithin and Gellan Gum. I know these can be troublesome for people with digestive issues but I’d be curious to learn more about these ingredients as well.

      • Meghanne – you may want to double check that. I occasionally buy Whole Foods unsweetened almond milk and it does indeed contain carageenan.

        • The Whole Foods 365 ORGANIC unsweetened almondmilk does not contain carageenan. I just purchased a container this weekend and double-checked the ingredients. Perhaps the regular one does, but the organic variety does not and it’s really not any more expensive.

          • My organic 365 unsweetened almond milk doesn’t have it. Could we all maybe be talking about shelf variety vs. refrigerated? I get the refrigerated and it does not have carrageenan. I am headed to wf in a bit so I will check the shelf version. BUT, HAS ANYONE noticed that since they took it off the shelf for a bit last summer and then reintroduced it a few months later, it separates strangely in coffee? More like the brands in Europe do. Complete bummer. I emailed them about it and it seemed to get better and then the batch I bought a couple of weeks ago started to separate out again! So something is different b/c my coffee and all other potential variables are unchanged.

          • But I believe some of those other brands that do not contain carageenan contain tri-calcium phosphate, and that seems to be a problem for me…. Same thing for the almond milks without added sugar; they either contain rice milk (which doesn’t work for me)

          • I think what makes me the most angry is that we are trusting these companies. It ca n be the same company with different ingredients. SO Coconut Milk doesn’t have the carageenan in it. I believe we need to make sure it is USDA Organic, non GMO.
            Also I was terribly upset today after purchasing Horizon, Organic whipping cream and finding carageenan in it.

            • What makes me most angry is realizing we are being poisoned for profit, things like the FDA are not protecting us.

        • That’s funny, I too buy the Whole Foods Organic 365 unsweetened Almond Milk and it does not contain carageenan which is why I buy it along with Silk.

      • Trader Joes and Whole Foods sell products without carrageenan in California BUT sell the same “looking and packaged” product in Minnesota – where I live, the DOES have carrageenan. Same carton, same name – different content. Why?

    • If anyone here is boycotting products that donate money towards the fight to keep GMO foods off the nutrition label or worse, as in this case, contain GMOs, should run from any Silk product. So if anyone is following the site author’s way of life of not eating what might be toxic should not want to consume Silk milk that uses soy because they do use genetically modified soy.

      My family tried many organic milks and decided on Kroger’s Simple Choice Organic Milk. There are a few different types including one soy milk that I would avoid because it might use GM soybeans. They have a nice chocolate almond milk. Now, of course, I need to check the ingredients on Simple Truth milks. I sincerely hope it doesn’t include carrageenan because we don’t want to start a new search for milk products!

      • you are shopping with ingredient BLINDERS on!

        ALL cocoa (and chocolate) are full of HEAVY METALS. they are all made in africa and are polluted. if you could only KNOW the health standards of the average african laborer. hah!
        now that is NOT some new-agey idea or controversial ingredient. It is 100% certainly bad for EVERY mammal and that’s been know for a long time.
        they screw up brains and nerve cells, cause permanent brain damage.

    • I am allergic to Carageenan and also to MSG. I have been told that it is very common for those people who react to MSG to have a similar reaction to Carageenan. I have not specifically noticed any digestive issues with Carageenan, but I do a wonderful boiled lobsters impersonation!! My skin gets swollen red and itchy particularly in my face!!

    • I can attest to the fact that carrageenan is a dangerous excitotoxin for some of us who are also sensitive to MSG and all forms of free glutamic acid. This would include the protein isolates that are the foundation of all the common protein supplements. I have sustained permanent nervous system injury as a result of ingesting these substances in medical grade supplements as well as accidental ingestion in prepared food, before I became aware of the source of my reactions. One of the supplements I reacted to was in fact composed exclusively of carrageenan and certain essential amino acids, and no other ingredients.

  18. Great article. I buy Hemp Bliss, which contains no carrageenan and tastes fine (although I never drink it on its own). It comes in sweetened and flavored varieties, but I buy the plain one.