Protein and Lysine as Factors in the Cariogenicity of a Cereal Diet

This investigation concerns the effect of certain alterations of a raw whole wheat diet on its cariogenicity for white rats. The alterations were: increasing the protein level by supplementation with dried egg white, casein and gluten at approximately equivalent nitrogen levels and by supplementation with the amino acids, L-lysine·HCl, DL-methionine, and DL-threonine. Littermate Sprague-Dawley strain rats were fed at weaning each series of comparative diets and maintained with them for 60 days. The criteria of carious experience were incidence and severity. The caries produced were the smooth surface type. Increasing protein level decreased the cariogenicity of the diets; dried egg white and casein supplementation decreased the cariogenicity of diets significantly more than did an equivalent gluten supplement; the supplementation of the diets by L-lysine·HCl, DL-methionine and DL-threonine did not result in a decrease of carious experience for these animals.