Short term vitamin E supplementation has no effect on platelet function, plasma phospholipase A2 and lyso-PAF in male volunteers.

1. Based largely upon in vitro studies, vitamin E has been reported to inhibit phospholipase A2 activity, to alter phospholipid metabolism and reduce platelet aggregation. 2. The effect of dietary supplementation with D-alpha-tocopherol (1500 iu/day for 14 days) was studied in nine males, 41-63 years old, comparing active treatment with a preceding placebo period. 3. Despite an increase from 2.6 +/- 0.8 (s.d.) x 10(-5) mol/L to 6.0 +/- 1.8 10(-5) mol/L in plasma vitamin E there were no significant changes in the aggregation of diluted whole blood or platelet rich plasma to adenosine diphosphate (ADP) or collagen, in plasma phospholipase A2 activity or plasma lyso-platelet-activating factor (lyso-PAF) (bioassay after in vitro acetylation to PAF). 4. High dose vitamin E dietary supplementation had no effect on these phospholipid and platelet parameters.