My wife has labile blood pressure that spikes really high.  Her
physican prescribed Toprol XL which didn't seem to help much until she
stopped using Vitamin E supplements when the blood pressure suddenly
stabilized.  We found one refence online (University of Maryland
website) theorizing that Vitamin E inhibits the effect of beta blockers
like Toprol, but have been unable to verify that information.

Last night, her blood pressure spiked again, after she had been eating
a lot of blueberries for a couple of days.  Is it possible that the
antioxidant effect of blueberries is acting the same as the vitamin E
in reducing the effect of Toprol?  Are there any studies that might
shed more light on this effect including other foods to be avoided?
Thank you very much.