The effect of malnutrition on saliva composition and caries development

Sammanfattning: Starvation and protein deficiency increase susceptibility to infec­tions in general and affect the function of various types of cells individually. Saliva contains substances which offer protection to the oral tissues. Its composition and secretion rate may be important in preventing the development of disease, e.g. dental caries. The aim of the present study was to evaluate the effects of starvation and protein deficiency on the secretion and composition of saliva and the effects possibly induced on dental caries.The following results were found.Short-term starvation on a liquid diet reduced the secretion rate and changed the composition of saliva in healthy humans. Chewing during starvation while it did not restore secretion rate, did partially restore the composition.Total protein concentration was not greatly affected by gross mal­nutrition or protein deficiency. A more pronounced effect was observed on individual biologically active proteins. The salivary glands seem not to be prime targets for malnutrition but the rate of biosynthesis of a bacteria aggregating glycoprotein and the activity of salivary peroxidase were significantly reduced by a long-term protein deficien­cy and gross malnutrition respectively in the rat. In humans, short­term starvation on a liquid diet caused an impaired glycosylation of sialic acid to the protein and decreased lysozyme activity. Sialylation was partially restored by chewing.In the rat the establishment of a cariogenic microorganism, S. cricetus (S. mutans) strain E 49 serotype a, was facilitated by protein deficiency.Starvation in both man and the rat produced evident clinical effects. The rate of plaque formation was increased in man and in the rat there was significant increase in caries development induced by a standardi­zed cariogenic challenge.This study shows that nutrition is important for the secretion of saliva and that starvation and protein deficiency increase the cario- genicity of sucrose.