I use Burgess SupaHamster (see
http://www.burgesssupafeeds.co.uk) which doesn't have any additives in either. Things like this seem to be added so the food looks more appetizing to us humans rather than for the animals benefit, which is completely loopy to me.
I haven't come across anything in journals about it, but then I haven't looked (and I'm on holiday at the moment
, so can't do it now!) but I think most things of this nature valid for rats will apply to hamsters pretty much equally.