I thought would add this.
Our HPLC method measures only alpha tocopherol. Most people who are not supplemented with alpha tocopherol have a level above 12 ug/ml, just from their diet. We have data on thousands of patients and just about none are deficient in vitamin E (<6.0 ug/ml) except for one case, a child who had a fat malabsorption problem. In fact, our vitamin E level increases with CoQ10 supplementation because CoQ10 'spares' our vitamin E.
The interference with CoQ10 absorption has been found with alpha tocopherol and ubiquinone by a Finnish group, led by Kaikkonen and we have also seen it (we presented it as a poster at a CoQ10 conference in 2005). With more than 300 IU alpha tocopherol/day added to CoQ10, not only does plasma CoQ10 level go down (by as much as 30%) but also the % oxidized CoQ10 increases. We have seen the same effect with ubiquinol supplementation.
We have no experience with other tocopherols or tocotrienols.
As far as the oxidized CoQ10 goes, we calculate % oxidized Q10 (ubiquinone) of total Q10 (sum of ubiquinone plus ubiquinol) and in our experience in healthy (CoQ10 unsupplemented) people, in plasma this is less that 2%. In CoQ10 supplemented people this % oxidized Q10 goes down even lower, often to <1%. Tissue % oxidized CoQ10 levels are much higher, but this is much more difficult to study.
Our body has enzyme systems which reduce CoQ10 to its reduced, ubiquinol form and other enzymes which oxidize it back to ubiquinone form. Both CoQ10 forms are vital. Ubiquinone is essential to our production of energy (ATP) and ubiquinol is essential for our antioxidant defense.
It is all pretty complex but I hope this helps,
Alena