Carrageenan
A thickening and gelling fibre extracted from red seaweed. Animal and lab studies link it to gut inflammation, and EU rules keep it out of formula fed to newborns.
If you have an inflammatory bowel condition such as ulcerative colitis or Crohn's, you may want to limit it. Listed as carrageenan or E407.
What is it?
A long-chain fibre extracted from red seaweed, used to thicken and set foods. Food-grade carrageenan is processed in alkali, which keeps its molecular weight high.
What does it do?
Thickens, gels and stabilises. Stops liquids separating and gives a smooth, set texture without fat.
Where you will see it
Plant milks, dairy and squirty cream, chocolate milk, ice cream, jellies and desserts, some processed and deli meats, cottage cheese and infant follow-on milks. On a label it reads as carrageenan or E407.
What the science says
Degraded carrageenan (poligeenan) is not the same as food-grade
The strongest cancer and ulcer findings come from poligeenan, also called degraded carrageenan, made by boiling carrageenan in strong acid for hours. It is a much shorter molecule and is not added to food. The two should not be treated as one substance, though regulators note the molecules overlap at the low-weight end.
IARC classifies degraded carrageenan (poligeenan) as possibly carcinogenic to humans (Group 2B) on animal evidence; food-grade carrageenan was not classifiable (Group 3).
Poligeenan is made by acid hydrolysis at near-boiling temperatures and is much shorter than food-grade carrageenan; it is not a component of carrageenan and is not formed from it in the gut.
EFSA could not fully confirm safety and kept the ADI temporary
In its 2018 re-evaluation EFSA could not confirm a firm acceptable daily intake. It made the existing group ADI of 75 mg per kg bodyweight per day temporary because of data gaps, and asked for the database to be improved within five years. A key gap was the lack of a validated method to measure the low molecular weight fraction, which is the part linked to possible harm.
EFSA judged the group ADI of 75 mg/kg bodyweight per day for carrageenan (E407) and processed Eucheuma seaweed (E407a) should be considered temporary, pending better data within five years.
EFSA flagged uncertainties on chemistry, exposure and toxicology, including the absence of a validated method to quantify the low molecular weight fraction and a lack of toxicology on that fraction.
Gut inflammation in animal and cell studies
In rodents and rabbits, carrageenan has produced colonic ulcers and inflammation resembling inflammatory bowel disease, alongside changes to the gut barrier, mucus layer and microbiome. These are animal and cell findings; how strongly food-grade carrageenan affects the human gut at normal intakes is not settled.
Review of animal experiments reported carrageenan produced ulcerations and inflammation of the colon with features resembling human inflammatory bowel disease.
Cell and animal evidence indicates carrageenan can disrupt the intestinal epithelial barrier, thin the mucus layer, alter the microbiome and stimulate pro-inflammatory signalling.
Small double-blind trial in ulcerative colitis patients in remission on a carrageenan-free diet: 3 of those given carrageenan capsules relapsed within a year versus none on placebo, but only 12 completed, so the result is preliminary.
Where it stands with the regulators
Who should be careful
People with ulcerative colitis, Crohn's or sensitive guts may choose to limit it. Parents should note it is not used in formula for newborns. Look for carrageenan or E407 on the label.
The honest read
Much online alarm conflates two different things. Poligeenan (degraded carrageenan) carries the cancer and ulcer evidence but is not added to food. Food-grade carrageenan is a separate, larger molecule. That said, EFSA could not fully confirm its safety, kept the ADI temporary over data gaps, and animal and cell studies point to gut inflammation, so the open questions are real rather than settled either way.
Related additives
Common questions
Is E407 (carrageenan) banned in the UK?
No. Carrageenan is an approved food additive in the UK and EU. Its ADI is currently temporary after EFSA flagged data gaps in 2018, and it is not permitted in formula for infants under 12 weeks.
Is carrageenan bad for your gut?
The strongest gut and cancer findings relate to degraded carrageenan (poligeenan), which is not added to food. Food-grade carrageenan has shown inflammatory effects in animal and cell studies, and a small human trial hinted at relapse in ulcerative colitis, but the effect at normal dietary intakes is not established.
What foods contain E407?
Plant milks, dairy drinks and creams, ice cream, jellies and desserts, some processed and deli meats, cottage cheese and follow-on infant milks. It appears as carrageenan or E407.
Is E407 vegan?
Yes. Carrageenan is extracted from red seaweed, so it is plant-derived and suitable for vegans and vegetarians.
Sources
- EFSA: Re-evaluation of carrageenan (E407) and processed Eucheuma seaweed (E407a) as food additives (2018)
- Clarifying the confusion between poligeenan, degraded carrageenan, and carrageenan (Crit Rev Food Sci Nutr, 2019)
- Review of harmful gastrointestinal effects of carrageenan in animal experiments (Tobacman, Environ Health Perspect, 2001)
- A randomized trial of the effects of the no-carrageenan diet on ulcerative colitis disease activity (Bhattacharyya et al., 2017)
Aaron Keen is the founder of NutraSafe. He researches and writes every additive entry himself, from the primary sources. About the research →
This is a guide, not medical advice. If an additive affects you, speak to your GP or a dietitian.
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