Carrageenan

Studies in people

• No harm found

  Cancer risk in people²

  Studies in people observed no cancer or tumors linked to carrageenan.

• Concern

  Blood sugar control³

  In people, carrageenan lowered blood sugar control in those who were overweight, but not in others.

• Concern

  Breast cancer rates⁴

  Carrageenan and other gums in food were linked to rising breast cancer rates in a time-trend analysis.

• Benefit

  Blood sugar after meals⁵

  In people, rice cooked with carrageenan led to lower blood sugar and a lower glycemic index than plain rice.

Animal and lab studies only

• Concern

  Inflammation evidence gap⁷

  In animal and lab studies, carrageenan triggered inflammation, but evidence in people is not yet definitive.

• Concern

  Gut health and inflammation⁸

  In animal studies, degraded carrageenan triggered gut ulcers, changed gut bacteria, and made the gut lining more leaky.

• Concern

  Gut inflammation in mice⁹

  In animal studies, carrageenan made gut inflammation worse in mice that already had it.

• Concern

  Gut lining and protein digestion¹⁰

  In lab studies, carrageenan interfered with protein breakdown and weakened the gut lining, but it is unclear if this happens in people.

• Concern

  Gut inflammation in Crohn's disease¹¹

  Carrageenan raised inflammatory signals in gut cells from Crohn's patients, especially when inflammation was already present.

• Concern

  Gut inflammation¹²

  In animal studies, carrageenan caused gut inflammation and ulcers like those in people, but its role in people is unclear.

• Concern

  Gut ulcers and tumours¹³

  In animal studies, carrageenan was linked to intestinal ulcers and tumours.

• Concern

  Immune system effects¹⁴

  In animal studies, carrageenan changed immune responses, but scientists do not yet know whether this happens in people.

• No harm found

  Gut and liver effects¹⁵

  In lab studies, carrageenan did not damage gut or liver cells or cause inflammation.

• Concern

  Gut and breast cell changes¹⁶

  In lab studies, carrageenan lowered the activity of several enzymes in human gut and breast cells.

• Concern

  Gut inflammation in animals¹⁷

  In animal studies, eating carrageenan led to gut inflammation, with signs of cell damage in the intestines.

• Concern

  Small intestine lining¹⁸

  In animal studies, carrageenan eaten daily for four weeks irritated the small intestine lining and sped up cell turnover.

• Concern

  Gut inflammation in rats¹⁹

  In animal studies, carrageenan eaten for weeks raised two inflammation markers tied to long-lasting gut irritation.

• Concern

  Small intestine changes²⁰

  In animal studies, eating carrageenan for a long time changed proteins in the small intestine.

Study type not stated

• Open question

  Gut health and digestion⁶

  More research is needed to know if carrageenan affects digestion, gut bacteria or inflammation in people.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Expert panels that weigh all the research. Shown for context: the signal at the top does not count them. IARC rates whether something can cause cancer at all, not how likely it is at the amounts in food.

• UN and WHO food additive experts (JECFA), 2014

  No daily limit needed (“ADI not specified”, JECFA’s term for very low toxicity).

• WHO cancer agency (IARC), 1987

  Not enough evidence to say whether it causes cancer in people (Group 3).