Oral Intake of Kappa-Carrageenan Food Additive Causes Enteritis

Carrageenans are polysaccharides isolated from several species of red algae of the Rhodophyceae family. Such hydrocolloids are formed by repeated residues of galactose and 3,6-anhydrogalactose. Carrageenan molecules are highly sulfated. The number and location of sulfate groups determine the type, form and functions of carrageenans. There are three main types of carrageenans: lambda, kappa and iota. All of them are actively used in the production of meat, dairy and confectionery products as gelling agents, emulsifiers, and thickeners. It has been shown in vivo that oral intake of carrageenan leads to the intestinal inflammation development. At the same time, opponents point out that carrageenan is safe. Our previous research demonstrated the ability of orally consumed lambda-carrageenan to induce enteritis in rats. The next stage is to study the impact of high-molecular-weight kappa-carrageenan (E407a), which is used in our country directly in the production of sausages and other meat products, on the body. The aim of the research was to study the features of the morphological state of small intestine, blood serum protein spectrum and some markers of inflammation in rats which were orally provided with a thickener kappa-carrageenan. Materials and methods. Twenty female white WAG rats were used in the experiment. They were randomly divided into two groups. Animals of the main group received 1% kappa-carrageenan solution daily orally for one month. Rats from the control group were provided with drinking water instead of carrageenan. Paraffin sections of small intestine were stained with hematoxylin-eosin, Einarsson's gallocyanin-chrome alum, and van Gieson's picrofuchsin. PAS-reaction was performed. Levels of middle-weight molecules, c-reactive protein and haptoglobin in blood serum of animals were measured spectrophotometrically. Blood serum protein spectrum was determined turbidimetrically. The data obtained in the research were statistically processed using the Graph Pad Prism 5 application. Results and discussion. A significant increase in the content of such markers of inflammation as middle-weight molecules, haptoglobin and C-reactive protein in the blood serum of the animals of the main group was found. The content of middle-weight molecules in serum was elevated 5.7 times in comparison with the control group. Haptoglobin levels were 1.9 times elevated, whereas C-reactive protein concentrations were 4.7 times higher. Such changes in serum concentrations of inflammation biomarkers indicate the development of the inflammatory process. The development of inflammation was proven morphologically. Analysis of blood serum protein spectrum revealed hypergammaglobulinemia, which might indicate the involvement of gut microflora in the inflammatory process. Conclusions. Kappa-carrageenan intake for one month leads to the development of enteritis, confirmed morphologically and biochemically. Changes in blood serum protein spectrum, namely the development of hypergammaglobulinemia, indicate the probable addition of the bacterial component to kappa-carrageenan-induced enteritis.