The best supplements are in liquid form - and B12 must be liquid or else it won't be absorbed fully. (I know this from experience lol - the powdered capsuled B-12 supplements are just rip-offs). Iron is best liquid too.
Make sure the brazil nuts you buy are in their shell (you'll have to pick up a nutcracker to open them at the grocery store), because shelled nuts are often moldy. http://www.herbalhut.com/detail.aspx?ID=15855
This is a site I found on google that sells them.