A review of salivary composition changes induced by fasting and its impact on health

Aripin, Nurul Fadhilah Kamalul; Zahid, N. Idayu; Rahim, Mohd Aizat Abdul; Yaacob, Hashim; Haris, Parvez I.; Rahim, Zubaidah Haji Abd.; Hashim, Roslan

doi:10.26599/fshw.2022.9250004

Cited by 8 publications

References 151 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Physiological regulation of oral saliva ion composition and flow rate are not coupled in healthy humans—Partial revision of our current knowledge required

Schwerdt,

Schulz,

Kopf

et al. 2024

Pflugers Arch - Eur J Physiol

View full text Add to dashboard Cite

Appropriate composition of oral saliva is essential for a healthy milieu that protects mucosa and teeth. Only few studies, with small sample numbers, investigated physiological saliva ion composition in humans. We determined saliva ion composition in a sufficiently large cohort of healthy adults and analyzed the effect of physiological stimulation. We collected saliva from 102 adults under non-stimulated and physiologically stimulated conditions (chewing). Individual flow rates, pH, osmolality, Na+, K+, Cl−, and HCO3− concentrations under both conditions as well as the individual changes due to stimulation (Δvalues) were determined. Non-stimulated saliva was hypoosmolal and acidic. Na+, Cl−, and HCO3− concentrations remained well below physiological plasma values, whereas K+ concentrations exceeded plasma values more than twofold. Stimulation resulted in a doubling of flow rates and substantial increases in pH, HCO3−, and Na+ concentrations. Overall, stimulation did not considerably affect osmolality nor K+ or Cl− concentrations of saliva. An in-depth analysis of stimulation effects, using individual Δvalues, showed no correlation of Δflow rate with Δion concentrations, indicating independent regulation of acinar volume and ductal ion transport. Stimulation-induced Δ[Na+] correlated with Δ[HCO3−] and Δ[Cl−] but not with Δ[K+], indicating common regulation of ductal Na+, Cl−, and HCO3− transport. We present a robust data set of human oral saliva ion composition in healthy adults and functional insights into physiological stimulation. Our data show (i) that flow-dependence exists for Na+ and HCO3− but not for K+ and Cl− concentrations, (ii) osmolality is flow-independent, (iii) regulation of Na+, Cl−, and HCO3− transport is coupled, (iv) regulation of flow rate and ion concentrations are independent and (v) spatially separated between acini and ducts, respectively.

show abstract