Enteral nutrition feeding alters antioxidant activity in unstimulated whole saliva composition of patients with neurological disorders

• The equilibrium oxidant/antioxidant is fundamental to maintain oral health.
• Total saliva of patients with enteral nutrition shows alterations in antioxidant properties.
• Patients with enteral nutrition are predisposed to oral disease triggered by oxidative stress.

Patients with neurological disorders have an increased risk of oral and systemic diseases due to compromised oral hygiene. If patients lose the ability to swallow and chew food as a result of their disorder, enteral nutrition is often utilized. However, this type of feeding may modify salivary antioxidant defenses, resulting in increased oxidative damage and the emergence of various diseases. The aim of this study was to evaluate the effects of enteral nutrition on biochemical parameters in the unstimulated whole saliva composition of patients with neurological disorders. For this, enzymatic (superoxide dismutase – SOD; glutathione peroxidase – GPx) and non-enzymatic (uric acid; ferric ion reducing antioxidant power – FRAP) antioxidant activity, as well as a marker for oxidative damage (thiobarbituric acid reactive substances – TBARS) were analyzed. Unstimulated whole saliva was collected from 12 patients with neurological disorders and tube-feeding (tube-fed group – TFG), 15 patients with neurological disorders and normal feeding via the mouth (non-tube-fed group – NTFG), and 12 volunteers without neurological disorders (control group – CG). The daily oral hygiene procedures of TFG and NTFG patients were similar and dental care was provided monthly by the same institution's dentist. All patients exhibited adequate oral health conditions. The salivary levels of FRAP, uric acid, SOD, GPx, TBARS, and total protein were compared between studied groups. FRAP was increased (p < 0.05) in the NTFG (4651 ± 192.5 mmol/mL) and the TFG (4743 ± 116.7 mmol/mL) when compared with the CG (1844 ± 343.8 mmol/mL). GPx values were lower (p < 0.05) in the NTGF (8.24 ± 1.09 mmol/min/mg) and the TFG (8.37 ± 1.60 mmol/min/mg) than in the CG (15.30 ± 2.61 mmol/min/mg). Uric acid in the TFG (1.57 ± 0.23 mg/dL) was significantly lower than in the NTFG (2.34 ± 0.20 mg/dL) and the CG (3.49 ± 0.21 mg/dL). Protein was significantly lower in the TFG (5.35 ± 0.27 g/dL) than in the NTFG (7.22 ± 0.57 g/dL) and the CG (7.86 ± 0.54 g/dL). There was no difference in the salivary flow rate and SOD between groups. Enteral nutrition in patients with neurological disorders was associated with lower oxidative damage, resulting in increased salivary antioxidant capacity. These results emphasize the importance of oral care for this population to prevent oral and systemic diseases.