Biochemical, immunological and enzymatic components of saliva in prolonged naso-gastric-fed elderly patients

Background and aims: We have previously shown that naso-gastric tube (NGT)-fed patients harbor pathogenic flora in their oropharynx. The purpose of this study was to examine comparatively the biochemical, immunological and enzymatic components of the saliva of these patients with that of orally-fed counterparts. Methods: The study group consisted of 19 elderly NGT-fed patients and 18 comparable patients on oral feeding. Unstimulated whole saliva was collected and analyzed according to accepted methods for sodium, potassium, chloride, uric acid, total protein, albumin, amylase, lysozyme, and immunoglobulins, IgM, IgG, IgA, as well as secretory IgA. Results: None of the above tested salivary components significantly differed between the two groups. Only uric acid levels were significantly lower (50%, p<0.05) in NGT-fed patients. Conclusions: Uric acid is the main antioxidant component of saliva and, as such, it may be related to pathogenic bacterial colonization of the oropharynx in NGT-fed patients, with the risk of aspiration pneumonia.