Title:Clinical Significance of Umami Taste and Umami-Related Gene Expression Analysis for the Objective Assessment of Umami Taste Loss
Volume: 22
Issue: 15
Author(s): Noriaki Shoji, Shizuko Satoh-Ku riwada and Takashi Sasano
Affiliation:
Keywords:
Umami taste, taste disorder (hypogeusia), malnutrition, filter paper disc (FPD) method, taste receptor, gene expression.
Abstract: Loss of umami taste sensation affects quality of life and causes weight loss and health problems, particularly
in the elderly. We recently expanded the use of the filter paper disc method to include assessment of umami
taste sensitivity, using monosodium glutamate as the test solution. This test showed high diagnostic performance
for discriminating between normal taste function and disorders in sensation of the umami taste, according to established
cut-off values. The test also revealed: (1) some elderly patients suffered from specific loss of umami taste
sensation with preservation of the other four taste sensations (sweet, salty, sour, and bitter); (2) umami taste disorder
caused a loss of appetite and decline in weight, resulting in poor health; (3) appetite, weight and overall health
improved after appropriate treatment for umami taste disorder. Because of the subjective nature of the test, however,
it may not be useful for patients who cannot express which taste sensation is induced by a tastant, such as
those with dementia. Most recently, using tissue samples collected from the tongue by scraping the foliate papillae,
we showed that evaluation of umami taste receptor gene expression may be clinically useful for the objective genetic diagnosis of umami
taste disorders.
