Glutamate concentration in whole saliva and taste responses to monosodium glutamate in humans

Abstract

It is universally accepted that saliva plays an important role in taste sensations. However, interactions between constituents of whole saliva and the five basic taste modalities are still poorly understood. The aim of the present study was to evaluate possible relationship between endogenous glutamate (Glu) levels in whole saliva and taste responses to a prototypic umami substance, monosodium glutamate (MSG; 0.03-10.0%). Rated intensity and pleasantness of MSG taste was studied in healthy volunteers divided into a high glutamate (HG) in saliva (HG; n = 19) and low glutamate in saliva (LG; n = 18) group based on the median split level of salivary Glu. The HG and LG group did not differ in terms of electrogustometric thresholds, rated intensity of the MSG samples and pleasantness of distilled water and the lower MSG concentrations (0.03-1.0%). Perceived intensity of water taste was significantly (P < 0.05) higher in the LG subjects. The LG group rated the higher MSG concentrations (3.0-10.0%) as more unpleasant (P < 0.01). The difference remained significant after controlling for a between-group difference in age. The present results suggest that individual differences in salivary Glu levels may alter hedonic responses to suprathreshold MSG concentrations.

Headache and mechanical sensitization of human pericranial muscles after repeated intake of monosodium glutamate (MSG)

“…Baseline salivary concentrations of glutamate remained constant and were not different between the MSG and placebo sessions. These concentrations are similar to a previous study that reported mean saliva concentrations of glutamate of 18±1 μM in 18 subjects [20]. However, administration of MSG tended to increase salivary glutamate concentration each day, which suggests the potential that accumulation might have been occurring.…”

Do facial reactions add new dimensions to measuring sensory responses to basic tastes?

“…On the receptor level, T1R1-T1R3 are responsible for the taste of umami (Galindo-Cuspinera & Breslin, 2006). Reactions to the umami taste have been described as neutral or pleasant (Nicklaus et al, 2005;Scinska-Bienkowska et al, 2006). It has further been found that the taste of IMP is probably caused by glutamic acid in saliva, since IMP itself has no umami taste (Yamaguchi, 1991).…”

Salivary secretion, taste and hyposalivation

“…Salivary glutamate is a possible component to modify the sensitivity of the taste receptor, although its concentration is far lower than the concentration necessary for the detection of its taste in humans (54). The taste of glutamate is recognized to be a basic taste, called ‘umami’, in addition to the basic four taste qualities (sweet, sour, salty and bitter).…”