Unfortunately, you cannot trade items. You will have to make sure all Pokemon being transferred do not have any hold items.
This is just to prevent items that are existent in Gen V but not existent to Gen VI to come through. For example, TMs that may have changed moves in Gen VI.
Also, if you mean transferring Pokemon from Gen V with items (migrating), that means your using PokeTransfer. It comes with PokeBank, that's why it's so easily confused. xD
Hope I helped. :)