Chronophysiological features of the normal mineral composition of human saliva

Background: The high rate of changes in the composition of saliva can be used for the monitoring of various biorhythms in order to study the physiological characteristics of the human body. Research objective: The study of the dynamics of the near-24-h mineral composition of saliva in men and women. Methods: The study involved 20 men and 20 women, age 23.1 +/- 0.9 years. Saliva samples were collected every 3 h during the day within 10 min. The mineral composition of saliva was defined by the capillary electrophoresis technique. The cross-group differences were evaluated using the non-parametric criterion. Results: It was shown that the maximum values of the mineralizing capacity fall to 7-8 a.m. and 18-19p.m., which is due to the change in the rate of saliva secretion. The near-24-h dynamics of the saliva pH practically coincides with the dynamics of the Ca/P ratio; there are evident maxima at 9:00 am and 15-18p.m. The values of the Na/K ratio are out of phase with the Ca/P ratio. There is one maximum, corresponding to 3 am in the night, and one minimum at 12-13p.m., which is due to a decreased level of sodium and increased potassium concentration. Statistically valid differences between men and women in pH (p < 0.001), concentrations of inorganic phosphorus (p < 0.001), as well as Ca/P coefficient (p = 0.011) were identified. Conclusion: The dynamics of the studied parameters during 24 h is characterized by pronounced intervals.