Moderate supplementation with natural alpha-tocopherol decreases platelet aggregation and low-density lipoprotein oxidation.
Previous studies have shown that oral administration of 300 mg alpha-tocopherol/day to healthy volunteers decreases platelet function and enhances their sensitivity to the platelet inhibitor, prostaglandin E(1), when full dose-response curves to a range of agonist concentrations are made. In this study, the effects of oral doses of natural alpha-tocopherol (75, 200 and 400 IU/day) were studied in order to determine whether the same effects might be achieved with lower intakes of vitamin E and whether inhibition is related to the platelet levels of the antioxidant in platelet membranes. Twenty two subjects undertook the supplementation regime, divided into three units of 2 weeks, each cycling through each of the dosages. The results show that uptake of vitamin E by the platelets was optimal at 75 IU/day, correlating with the maximal influence on platelet aggregation and platelet responsiveness to inhibition by PGE1, increased supplemental levels exerting no greater effects.
Mabile
L
L
International Antioxidant Research Centre, UMDS-Guy's Hospital, St Thomas's Street, Kings College-Guy's Campus, London, UK.
Bruckdorfer
K R
KR
Rice-Evans
C
C
D000255:Adenosine Triphosphate / Q000378:metabolism; D000284:Administration, Oral; D000328:Adult; D000527:Alprostadil / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D014810:Vitamin E / Q000008:administration & dosage* / Q000097:blood; D001620:beta-Thromboglobulin / Q000378:metabolism
D008055:Lipids; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D010975:Platelet Aggregation Inhibitors; D001620:beta-Thromboglobulin; D014810:Vitamin E; D000255:Adenosine Triphosphate; D000527:Alprostadil