On first inspection, the food additive called carrageenan seems quite harmless. Derived from the edible red seaweed (Chondrus crispus) or Irish or Carrageen Moss, it has been used for some 600 years as a thickening agent for foods.
Today, it is a popular vegetarian alternative to gelatin and is found in many common foods like almond, rice, soy and coconut milks, ice creams, cottage cheese, yogurts, creamers, salad dressings, desserts, sauces, diet sodas, processed meats, vegetarian meats, beers, toothpastes and more.
The original research, performed back in 1982, suggested that food-grade carrageenan was quite safe, (1) but new evidence, which points out the flaws in those early studies, suggests that food-grade carrageenan may be a bowel irritant and carcinogen. (2,3,5) While the evidence against food-grade carrageenan is compelling, there are many studies suggesting it presents no health risks. (1,4) As a result, both the FDA and the EU (European Union) continue to regard it as a safe food additive.
Let’s dig in…
There are two basic forms of carrageenan:
1. Un-degraded (non-toxic, food-grade)
The un-degraded carrageenan was thought to have too large a molecular weight to be absorbed through the intestinal tract, and it was reported that it had no negative impact on intestinal health. (1)
It should be known that if the food-grade carrageenan was to penetrate the blood stream, there were a variety of harmful effects measured – most notably on the immune system. (1)
It should also be known that there are many studies suggesting that un-degraded (food-grade) carrageenan is a bowel irritant, toxin and carcinogen in animals. (2,3,5)
2. Degraded (toxic, non-food grade)
The degraded carrageenan (also known as poligeenan) has a lower molecular weight and therefore easily penetrates, irritates and absorbs through the intestinal tract. (1) It is not an approved food additive and has been found to present a variety of toxicological, inflammatory and carcinogenic risk factors to the intestinal tract in humans. (2,3,5)
Toxic or Not?
The degraded (non-food grade) form of carrageenan is a known toxin, and the un-degraded (food-grade) form is considered safe in some studies and unsafe in others. (2,3,5)
Based on a meta-analysis of many studies on the safety of food-grade carrageenan by Dr. Tobacman, there are documented toxic effects (bowel ulcerations) of the un-degraded (food-grade) carrageenan in humans and carcinogenic effects in animals. (3) In her thorough review, the studies suggest that the so-called safe un-degraded carrageenan is actually broken down into the degraded or toxic form of carrageenan by the digestive stomach acid and during processing by food manufacturers. (2,3)
If these studies are accurate, the food-grade carrageenan that is so common in the American diet may be responsible, in part, for many of the bowel inflammatory cases and may also be acting as a silent carcinogen. (2,3,5)
Again, this conclusion is not shared by the FDA and many food safety organizations in both the USA and the European Union because there are many studies suggesting un-degraded carrageenan is perfectly safe. (1,4)
Potential Blood Sugar Risk
In one recent study, un-degraded carrageenan was shown to impair glucose tolerance and increase insulin resistance by inhibiting the effects of insulin. (6) This is the first study that has shown the effects of un-degraded (food-grade) carrageenan outside the intestinal tract, indicating that, while we have been promised it will not pass through the intestinal tract, it actually may be doing just that.
Perhaps the easiest way to sum up this review of carrageenan is to say what we know for sure. Carrageenan is a processed food. Even the most conservative medical doctors are suggesting we cut back or stop eating processed foods. While no one can say for sure about the health risks of carrageenan, my advice is to better be safe than sorry and to avoid it as best you can. Becoming aware of how to avoid it will only help us all be better at avoiding processed foods.
- Cohen SM1, Ito N. A critical review of the toxicological effects of carrageenan and processed eucheuma seaweed on the gastrointestinal tract. Crit Rev Toxicol. 2002 Sep;32(5):413-44.
- Safety of Carrageenan in Foods.
- Joanne K. Tobacman.Review of Harmful Gastrointestinal Effects of Carrageenan in Animal Experiments.College of Medicine, University of Iowa, Iowa City, Iowa, USA.
- Weiner ML1. Food additive carrageenan: Part II: A critical review of carrageenan in vivo safety studies. Crit Rev Toxicol. 2014 Mar; 44(3): 244-69.
- Tobacman JK1. Review of harmful gastrointestinal effects of carrageenan in animal experiments. Environ Health Perspect. 2001 Oct;109(10):983-94.
- Bhattacharyya S1, O-Sullivan I, Katyal S, Unterman T, Tobacman JK. Exposure to the common food additive carrageenan leads to glucose intolerance, insulin resistance and inhibition of insulin signalling in HepG2 cells and C57BL/6J mice. Diabetologia. 2012 Jan;55(1):194-203.
Author: Dr. John Douillard
Editor: Renée Picard
Photo: Wiki Commons