Deterioration of Oral Functions and Nutrition in Older Individuals

Purpose of Review: Oral functions, which are responsible for feeding and swallowing, play a very important role in obtaining proper nutrition. Therefore, their deterioration could interfere with nutritional ingestion. This review investigated previous reports on the relationship between oral function deterioration and malnutrition. Recent Findings: Reduced occlusal force, decreased tongue–lip motor function, decreased tongue pressure, decreased masticatory function, and deterioration of swallowing function have been found to be associated with malnutrition. On the other hand, consensus does not exist on whether oral dryness is associated with malnutrition. Prosthetic rehabilitation and oral function training are effective interventions for improving oral functions. However, malnutrition could not be addressed by prosthetic rehabilitation alone; it requires simultaneous management with prosthetic rehabilitation and nutritional guidance. Furthermore, it has been reported that data on whether oral function training, such as tongue strengthening training, could improve malnutrition are limited. Summary: Partial deterioration of oral functions can cause malnutrition. Prosthetic rehabilitation and oral function training could be considered interventions for improving malnutrition, but numerous unclarified points about these methods remain. In the future, detailed research should be conducted to elucidate the causal relationship between deterioration of oral functions and malnutrition and to establish oral function interventions for improving malnutrition.