Chronic and subchronic effects of various forms of carrageenan in rats

The subchronic and chronic toxicity of undegraded (native) carrageenan with respect to botanical source, and type of polymer chain (kappa, lambda, and iota) was investigated in rats for 13 to 39 weeks. The carrageenans were incorporated in the diet at 1 or 5% w/w. In all instances comparable levels of Alphacel were used. In the study designed to determine if there were any differences between various strains of rat, the Osborne-Mendel rat was used in addition to the Sprague-Dawley strain. Only the Sprague-Dawley strain was used in the other studies. Parameters utilized for detecting toxicity included mortality, body weights, fecal occult blood, hematologic indices, clinical chemistry, gross and microscopic histology, and evidence of carrageenan storage. Except for minor changes, no evidence was obtained for any direct effect of the carrageenans on the liver or the gastrointestinal tract.