Effects of environmental temperature on saliva flow rate and secretion of protein, amylase and mucin 5B

Abstract

Objective: The aim of this study is to evaluate the short term effects of environmental temperature on saliva flow rate and composition.

Methods: In a cross-over study design 20 subjects (18-25 years old, 14 women, 6 men) were exposed in randomized order at different days to three temperatures (4 °C, 21 °C and 37 °C). Five minutes after a subject was exposed to the test temperature, collection of resting saliva was started for 5 min at the same temperature. Saliva flow rate, pH, viscosity, protein concentration, mucin 5B concentration and amylase activity were measured.

Results: Exposure to 4 °C resulted in an increase of the saliva flow rate (p < 0.01), protein output and amylase output (p < 0.001) compared to exposure to 21 °C or 37 °C. Although the figures for mucin 5B output at 4 °C were higher than at higher temperatures, this was not significant. There were no significant differences in the salivary mucin 5B concentration and viscosity between saliva samples collected at the indicated temperatures.

Conclusions: Lowering of the temperature induces an increase in saliva flow rate, as well as protein and amylase output.

Keywords: Amylase; Heat; Viscosity; saliva secretion.