title: Overestimation of salivary 25-hydroxyvitamin D3 level when using stimulated saliva with gum-chewing.
abstract: BACKGROUND
  The measurement of 25-hydroxyvitamin D3 [25(OH)D3] in whole saliva can be a noninvasive tool for assessing vitamin D status. Gum-chewing increases salivation and is often used to collect an adequate sample volume of saliva within a shorter time. The aim of this study was to clarify whether the concentration of 25(OH)D3 in whole saliva is influenced by gum-chewing.
  
  
  METHODS
  Stimulated saliva was collected from healthy volunteers chewing a tasteless and flavorless chewing gum after unstimulated saliva was collected without gum-chewing. The salivary 25(OH)D3 and albumin concentrations were measured.
  
  
  RESULTS
  The salivary 25(OH)D3 concentration was reproducibly measured when saliva was collected without gum-chewing, whereas the concentration was significantly increased by gum-chewing (p<0.05, paired t-test). One of the causes for the gum-chewing-induced increase in the 25(OH)D3 concentration may be the increased amount of protein-bound 25(OH)D3 in whole saliva.
  
  
  CONCLUSIONS
  Stimulated saliva by gum-chewing should be used with caution in the measurement of 25(OH)D3. The protein binding rate in plasma is a significant consideration when predicting whether the salivary concentration of a compound is varied by gum-chewing.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan. higashi@rs.tus.ac.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Higashi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Hijikuro
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Yamagata
authors.forename: Shoujiro
authors.initials: S
authors.lastname: Ogawa
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism; D002112:Calcifediol / Q000378:metabolism*; D002638:Chewing Gum; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D008409:Mastication / Q000502:physiology; D012463:Saliva / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism; D055815:Young Adult
chemical_list: D000418:Albumins; D002638:Chewing Gum; D013739:Testosterone; D002112:Calcifediol
keywords: 25-Hydoxyvitamin D(3); Gum-chewing; Protein-binding rate; Saliva