40 mg isn't a high dose, but it can be for some people. If you experience side effects from Vitamin A overdose you are consuming too much:

http://en.wikipedia.org/wiki/Hypervitaminosis_A

That is why it is so important to get blood tests every month.

I never went higher than 40 mg and still ate vitamin A foods everyday (spinach/sweet potato). However I got horrible rashes, hair loss, and got sick a lot throughout

treatment. This has all gone away since (1 month after accutane)

If the vitamin A from foods you're consuming is beta carotene, then you don't need to worry about that type of vitamin A. There's no toxicity associated with consuming excess beta carotene. You might turn orange though.

Accutane isn't actually vitamin A. It's a derivative.