Carageenan explained in Wikipedia
- extracted from red seaweed (Rhodophyceae family)
- sulphated
- oligosaccharide (polymeric carbohydrate)
- in the food industry, carrageenans are used as stabilizers, thickners, texturizers, emulsifiers, gelation, suspension, water binding, texture enhancers
- processed foods with carrageenan include: deli meat, hams, chocolate milk, ice cream, sour cream, butter milk, cottage cheese, egg nog, evaporated milk, soy milk, infant formula, water gel, puddings, flan, pie fillings, toaster pastries, fruit toppings, frust syrups, fruit strips, cheese sauces, cake glazes, batters, frozen dough (see Ingredients Solutions for more info)
- kappa-carrageenan has properties of gel and is used in breading and batter
- kappa2-carrageenan has properties of gelling and thickening and is used primarily for milk
- lambda carrageenan has binding properties, helps to retain moisture, and contributes to viscosity and is used in sweet doughs and to thicken dairy products
- iota carrageenan has gel properties and is used in fruit products
- carrageenan degrades with high heat and acidity
- degraded carrageenan is called polygeenan
"
Review of harmful gastrointestinal effects of carrageenan in animal experiments", Tobacman in
Environ Health Perspect (2001)
" Review of these data demonstrated that exposure to undegraded as well as to
degraded carrageenan was associated with the occurrence of
intestinal ulcerations and neoplasms. This association may be attributed to contamination of undegraded carrageenan by components of low molecular weight, spontaneous metabolism of undegraded carrageenan by acid hydrolysis under conditions of normal digestion, or the interactions with intestinal bacteria. ... Because of the acknowledged carcinogenic properties of degraded carrageenan in animal models and the
cancer-promoting effects of undegraded carrageenan in experimental models, the widespread use of carrageenan in the Western diet should be reconsidered." [emphases mine]
c.f. "
A critical review of the toxicological effects of carrageenan and processed eucheuma seaweed on the gastrointestinal tract", Cohen in Crit Rev Toxicol (2002)
"Carrageenan is not degraded to any extent in the gastrointestinal tract and is not absorbed from it in species examined, such as rodents, dogs, and non-human primates. Systemically administered carrageenan has been reported to have a variety of effects, particularly on the immune system, but these are not pertinent to orally administered carrageenan. The substance poligeenan (formerly referred to as degraded carrageenan) is not a food additive. It exhibits toxicological properties at high doses that do not occur with the food additive carrageenan. In-long term bioassays, carrageenan has
not been found to be carcinogenic, and there is
no credible evidence supporting a carcinogenic effect or a tumor-promoting effect on the colon in rodents. Also, like many dietary fibers, there is significant cecal enlargement in rodents when it is administered at high doses, but this does not appear to be associated with any toxicological consequences to the rodent. Many toxicological studies on carrageenan have involved administration at doses in excess of today's standards for dietary feeding levels in bioassays, and they are orders of magnitude in excess of those to which humans are exposed."
"
Carrageenan: Response", Tobacman,
Environmental Health Perspectives (2002)
"It is difficult to recognize a wolf in sheep's clothing. This seems to be the situation with regard to carrageenan. ... Extensive experimental data have demonstrated that
a) degraded carrageenan produces neoplasms and ulcerations in animal models;
b) acid hydrolysis, such as occurs in the stomach, leads to the production of degraded carrageenan from food-grade carrageenan; and
c) food-grade carrageenan contains significant amounts of degraded carrageenan. Human consumption of carrageenan has been increasing steadily in the United States in the 20th century."
"
A 90-day dietary study on kappa carrageenan with emphasis on the gastrointestinal tract", Weiner
et al. in
Food Chem Toxicol (2007)
"Clinical signs were limited to soft feces in high dose rats and to a lesser extent in low dose rats. There were no treatment-related effects on body weights, urinalysis, hematology or clinical chemistry parameters, or on organ weights or ophthalmic, macroscopic or microscopic findings."
"
Degraded carrageenan causing colitis in rats induces TNF secretion and ICAM-1 upregulation in monocytes through NF-kappaB activation" in
PLoS One (2010)
From Abstract: "Carrageenan (CGN) is a high molecular weight sulphated polysaccharide derived from red seaweeds. In rodents, its
degraded forms (dCGN) can induce intestinal inflammation associated with macrophage recruitment and activation. ...
These data strongly suggest that the degraded forms of CGN have a pronounced effect on monocytes, characteristic of an inflammatory phenotype." [emphasis mine]
"All rats developed
diarrhea during degraded carrageenan administration and gross evidence of
blood was frequently detected in the stools. ... Histological examination revealed various degrees of
mucosal inflammation. ... More
severe mucosal injuries including ulceration, hyperplastic epithelium, crypt distortion and a strong macrophage infiltration, were observed in the 40 kDa dCGN-treated rats. ... Treatment with dCGN also induced a
strong aggregation of monocytes, detected by phase contrast inverse microscopy (
Fig. 5). Although this effect was easily observed in monocytes incubated with the 10 kDa dCGN (
Fig. 5B), a more robust cell aggregation was observed in monocytes incubated with the 40 kDa dCGN. ... Although native form CGN (200–800 kDa) has been declared harmless to humans
[8], its degraded forms (<50 kDa), also known as
poligeenan, are widely used to induce colitis in rodents [3]–
[5]. These degraded CGN may also have a possible
carcinogenic effect [4],
[6]–
[8]; however this is still controversial. ... it is probable that some dCGN are produced by acid hydrolysis during gastric digestion
[9],
[10] or interaction with intestinal bacteria
[11],
[12]. Thus, understanding the mechanisms of dCGN-induced bowel inflammation is of great importance. In this report, we have analyzed the role of human monocytes (PBM and THP-1) in dCGN-induced inflammation. ... Preliminary
in vivo studies in rats treated with dCGN revealed significant
shortening of the large intestine associated with an inflammatory state,
i.e. strong infiltration of macrophages to the intestinal mucosa similar to DSS-induced inflammation. ... These results suggest that monocytes might produce cytokines associated with activation into macrophages in response to dCGN. ... [I]t is possible that TLR4 is activated by dCGN to induce cytokine secretion by monocytes. ... Thus, degraded CGN clearly can activate monocytes to express an increased number of ICAM-1 adhesion molecules, therefore being
capable of creating the conditions characteristic of Crohn's disease symptomatology,
i.e. PBM accumulation and MGC formation. ... We presume that the differential effects of 10 and 40 kDa dCGN to induce these effects on monocytes are tightly linked to their capacity to induce inflammation
in vivo. However,
in vivo, macrophages do not come in direct contact with the intestinal lumen and are separated by the epithelial barrier.
The way by which dCGN may leave the intestinal lumen and cross the epithelial barrier to reach the macrophages is an intriguing open question. One possible explanation resides in the potential of dCGN to “induce”
cellular and paracellular injurious effects at the intestinal epithelial cell monolayer. ... These results suggest that,
although CGN is widely used as a food additive, its degraded forms have an important effect on monocytes characteristic of an inflammatory phenotype." [emphases mine]
Carrageenan and the Acceptance of Food Additive Toxicity, 1950-2000 by Mariel Wolfson (2008), published on
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