Timing of antioxidant vitamin ingestion alters postprandial proatherogenic serum markers.
BACKGROUND
This study was designed to determine the optimal timing of vitamins E and C to prevent oxidative stress induced by a high-fat evening meal in type 2 diabetes.


RESULTS
Eleven subjects were admitted on 4 occasions. Euglycemia was maintained for 24 hours by insulin infusion. Participants were fed a high-fat test supper equivalent to a McDonald's Big Mac Meal. Blood was drawn for measurement of C-reactive protein (CRP), interleukin 6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), malonyldialdehyde (MDA), and total radical antioxidant parameter (TRAP) before and during the 4 hours after the test meal. Studies were performed in random sequence with vitamin E 800 IU and vitamin C 1 g given either before breakfast or before supper in a double-blind manner on the day of the test meal. Control studies were performed with no vitamins and no test meal administered. There was a significant rise in CRP and PAI-1 after the test supper (P<0.05 compared with "no meal"). Either presupper or prebreakfast vitamins E and C prevented the meal-induced rise in CRP (P=0.03), although presupper vitamins were more effective (P=0.03 compared with prebreakfast vitamins). Only prebreakfast vitamins prevented the meal-induced rise in PAI-1 (P=0.006). There were no significant meal-related changes in the concentrations of IL-6, MDA, or TRAP.


CONCLUSIONS
The timing of administration of antioxidant vitamins has variable effects on markers of meal-induced inflammation and fibrinolysis. This observation may be one reason why cardiovascular disease prevention trials using these vitamins have reported conflicting results.
Carroll
Mary F
MF
University of New Mexico School of Medicine, Albuquerque, NM 87131, USA. mcarroll@salud.unm.edu
Schade
David S
DS
D000284:Administration, Oral; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000187:drug effects; D002097:C-Reactive Protein / Q000032:analysis; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D004041:Dietary Fats; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D016166:Free Radical Scavengers / Q000097:blood; D015309:Glucose Clamp Technique; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D019518:Postprandial Period; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014810:Vitamin E / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage*
D000975:Antioxidants; D015415:Biomarkers; D001786:Blood Glucose; D004041:Dietary Fats; D016166:Free Radical Scavengers; D015850:Interleukin-6; D017395:Plasminogen Activator Inhibitor 1; D014280:Triglycerides; D014815:Vitamins; D014810:Vitamin E; D008315:Malondialdehyde; D002097:C-Reactive Protein; D001205:Ascorbic Acid