title: Oxidative stress is increased in critically ill patients according to antioxidant vitamins intake, independent of severity: a cohort study.
abstract: BACKGROUND
  Critically ill patients suffer from oxidative stress caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Although ROS/RNS are constantly produced under normal circumstances, critical illness can drastically increase their production. These patients have reduced plasma and intracellular levels of antioxidants and free electron scavengers or cofactors, and decreased activity of the enzymatic system involved in ROS detoxification. The pro-oxidant/antioxidant balance is of functional relevance during critical illness because it is involved in the pathogenesis of multiple organ failure. In this study the objective was to evaluate the relation between oxidative stress in critically ill patients and antioxidant vitamin intake and severity of illness.
  
  
  METHODS
  Spectrophotometry was used to measure in plasma the total antioxidant capacity and levels of lipid peroxide, carbonyl group, total protein, bilirubin and uric acid at two time points: at intensive care unit (ICU) admission and on day seven. Daily diet records were kept and compliance with recommended dietary allowance (RDA) of antioxidant vitamins (A, C and E) was assessed.
  
  
  RESULTS
  Between admission and day seven in the ICU, significant increases in lipid peroxide and carbonyl group were associated with decreased antioxidant capacity and greater deterioration in Sequential Organ Failure Assessment score. There was significantly greater worsening in oxidative stress parameters in patients who received antioxidant vitamins at below 66% of RDA than in those who received antioxidant vitamins at above 66% of RDA. An antioxidant vitamin intake from 66% to 100% of RDA reduced the risk for worsening oxidative stress by 94% (ods ratio 0.06, 95% confidence interval 0.010 to 0.39), regardless of change in severity of illness (Sequential Organ Failure Assessment score).
  
  
  CONCLUSIONS
  The critical condition of patients admitted to the ICU is associated with worsening oxidative stress. Intake of antioxidant vitamins below 66% of RDA and alteration in endogenous levels of substances with antioxidant capacity are related to redox imbalance in critical ill patients. Therefore, intake of antioxidant vitamins should be carefully monitored so that it is as close as possible to RDA.
authors.affiliation: Nutrition and Dietary Unit, Virgen de las Nieves Hospital, Fuerzas Armadas Avenue, 18014 Granada, Spain. jimena@fundacionhvn.org
authors.forename: Jimena
authors.initials: J
authors.lastname: Abilés
authors.forename: Antonio Pérez
authors.initials: AP
authors.lastname: de la Cruz
authors.forename: José
authors.initials: J
authors.lastname: Castaño
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Elvira
authors.forename: Eduardo
authors.initials: E
authors.lastname: Aguayo
authors.forename: Rosario
authors.initials: R
authors.lastname: Moreno-Torres
authors.forename: Juan
authors.initials: J
authors.lastname: Llopis
authors.forename: Pilar
authors.initials: P
authors.lastname: Aranda
authors.forename: Sandro
authors.initials: S
authors.lastname: Argüelles
authors.forename: Antonio
authors.initials: A
authors.lastname: Ayala
authors.forename: Alberto Machado
authors.initials: AM
authors.lastname: de la Quintana
authors.forename: Elena Maria
authors.initials: EM
authors.lastname: Planells
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D016638:Critical Illness / Q000453:epidemiology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D017382:Reactive Oxygen Species / Q000097:blood; D012720:Severity of Illness Index; D014815:Vitamins / Q000008:administration & dosage* / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species; D014815:Vitamins