Efeito da administração de uma dieta enteral com antioxidantes sobre as concentrações plasmáticas de tióis totais, carbonilas de proteínas e malondialdeído após acidente vascular cerebral

OBJECTIVE: The aim of this study was to assess the effect of a commercial enteral diet with added antioxidants on total plasma thiol, protein carbonyl and malondialdehyde levels of stroke survivors. METHODS: Fourteen patients from a general hospital who had been started on enteral nutrition 48 hours after a stroke were included in the study. The exclusion criteria were multiple organ dysfunction syndrome, liver failure and morbid obesity associated with diabetes Mellitus. The commercial diet was fed by continuous drip via infusion pump and contained mixed carotenoids, vitamins C and E, and the minerals selenium, zinc and copper. Blood samples were collected at baseline and after 5 days of enteral diet, but only from patients whose diet intake met their total energy expenditure. Total plasma thiol and protein carbonyl levels were determined by Ellman's reagent and dinitrophenylhydrazine, respectively. Plasma malondialdehyde levels were measured by the assay of thiobarbituric acid reactive substances. RESULTS: The mean age of the sample was M=70.3 years, (SD=14.1). All patients received more than 100% of the Dietary Reference Intakes for the abovementioned antioxidants but none exceeded the tolerable upper limit. Plasma thiol and malondialdehyde levels did not vary over time but protein carbonyl levels were significantly higher (p=0.034), especially in intubated patients (p=0.048). CONCLUSION: Biomarker determinations showed that a commercial enteral diet with added antioxidants did not reduce oxidative stress.