title: Short-term, moderate dosage Vitamin E supplementation may have no effect on platelet aggregation, coagulation profile, and bleeding time in healthy individuals.
abstract: OBJECTIVE
  To investigate the in vivo effect of short-term, moderate dosage synthetic dl-alpha-tocopherol acetate supplementation on platelet aggregation, coagulation profile, and simulated bleeding time in healthy individuals. alpha-tocopherol is the most biologically active isomer of Vitamin E, traditionally promoted as an antioxidant and therapeutic agent in cardiovascular disease. In vitro studies have suggested that alpha-tocopherol plays a role in the inhibition of platelet aggregation. However, further investigations into the effect of alpha-tocopherol on bleeding in vivo have not duplicated these findings.
  
  
  METHODS
  A total of 42 healthy volunteers complied with a 2-week abstinence period from the use of anti-platelet agents followed by determination of baseline platelet aggregation properties and coagulation studies using citrated whole blood. Moderate dosage Vitamin E (800 IU of dl-alpha-tocopherol acetate) was then self-administered for 14 days with reevaluation of platelet aggregation and coagulation profile, and simulated bleeding time after 14 days of Vitamin E supplementation.
  
  
  RESULTS
  Forty subjects completed the 4-week study period. All 40 subjects demonstrated normal baseline coagulation studies and all had collagen-stimulated platelet aggregation assessment performed in triplicate. After Vitamin E supplementation, no significant difference was demonstrated in any study parameter.
  
  
  CONCLUSIONS
  Dietary supplementation with moderate dosage synthetic dl-alpha-tocopherol acetate did not significantly prolong bleeding or platelet aggregation in vivo. The affect of Vitamin E on platelet aggregation in vitro does not appear to be reproducible in vivo. Therefore, peri-operative discontinuation of Vitamin E may not be necessary.
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic Arizona, Scottsdale, USA.
authors.forename: Nina H
authors.initials: NH
authors.lastname: Dereska
authors.forename: Elisabeth C
authors.initials: EC
authors.lastname: McLemore
authors.forename: Deron J
authors.initials: DJ
authors.lastname: Tessier
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Bash
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Brophy
mesh_terms: D000244:Adenosine Diphosphate / Q000097:blood; D001760:Bleeding Time; D001777:Blood Coagulation / Q000187:drug effects / Q000502:physiology*; D001800:Blood Specimen Collection; D003094:Collagen / Q000097:blood; D019587:Dietary Supplements; D004837:Epinephrine / Q000097:blood; D006801:Humans; D019934:International Normalized Ratio; D010314:Partial Thromboplastin Time; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D011517:Prothrombin Time; D012016:Reference Values; D014810:Vitamin E / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014810:Vitamin E; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine