title: Antioxidant enriched enteral nutrition and oxidative stress after major gastrointestinal tract surgery.
abstract: OBJECTIVE
  To investigate the effects of an enteral supplement containing antioxidants on circulating levels of antioxidants and indicators of oxidative stress after major gastrointestinal surgery.
  
  
  METHODS
  Twenty-one patients undergoing major upper gastrointestinal tract surgery were randomised in a single centre, open label study on the effect of postoperative enteral nutrition supplemented with antioxidants. The effect on circulating levels of antioxidants and indicators of oxidative stress, such as F2-isoprostane, was studied.
  
  
  RESULTS
  The antioxidant enteral supplement showed no adverse effects and was well tolerated. After surgery a decrease in the circulating levels of antioxidant parameters was observed. Only selenium and glutamine levels were restored to pre-operative values one week after surgery. F2-isoprostane increased in the first three postoperative days only in the antioxidant supplemented group. Lipopolysaccharide binding protein (LBP) levels decreased faster in the antioxidant group after surgery.
  
  
  CONCLUSIONS
  Despite lower antioxidant levels there was no increase in the circulating markers of oxidative stress on the first day after major abdominal surgery. The rise in F2-isoprostane in patients receiving the antioxidant supplement may be related to the conversion of antioxidants to oxidants which raises questions on antioxidant supplementation. Module AOX restored the postoperative decrease in selenium levels. The rapid decrease in LBP levels in the antioxidant group suggests a possible protective effect on gut wall integrity. Further studies are needed on the role of oxidative stress on outcome and the use of antioxidants in patients undergoing major abdominal surgery.
authors.affiliation: Department of Surgery, VU University Medical Center Amsterdam, PO box 7057, 1007 MB Amsterdam, The Netherlands.
authors.forename: Mireille F M
authors.initials: MF
authors.lastname: van Stijn
authors.forename: Gerdien C
authors.initials: GC
authors.lastname: Ligthart-Melis
authors.forename: Petra G
authors.initials: PG
authors.lastname: Boelens
authors.forename: Peter G
authors.initials: PG
authors.lastname: Scheffer
authors.forename: Tom
authors.initials: T
authors.lastname: Teerlink
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Twisk
authors.forename: Alexander P J
authors.initials: AP
authors.lastname: Houdijk
authors.forename: Paul A M
authors.initials: PA
authors.lastname: van Leeuwen
mesh_terms: D000209:Acute-Phase Proteins; D000293:Adolescent; D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D002352:Carrier Proteins / Q000097:blood; D019587:Dietary Supplements; D013505:Digestive System Surgical Procedures; D004750:Enteral Nutrition; D028441:F2-Isoprostanes / Q000097:blood; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D011183:Postoperative Complications / Q000097:blood / Q000178:diet therapy* / Q000503:physiopathology; D011446:Prospective Studies; D055815:Young Adult; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D000975:Antioxidants; D002352:Carrier Proteins; D028441:F2-Isoprostanes; D008562:Membrane Glycoproteins; D000099231:Lipopolysaccharide-Binding Protein