400 IU of vitamin E is a very large dose. Vitamin E is a potent anticoagulant and large doses must be used with care. When I used to take vitamin E 400 IU years ago, I had nosebleeds. I now either take no vitamin E supplementation, or perhaps around 100 IU a day or so that is in a multivitamin. If you feel you don't get enough vitamin E in your diet, then perhaps take 100 IU a day.

Some supplements are safe to take at many times the RDA, while others aren't. Vitamin c is one supplement that is safe at high dosages if you use a buffered form. If you take too much vitamin c, you might get diarrea, then you know you need to cut back.
I take 2-3 grams a day of vitamin c, while others here take even more.