I have used powdered metals together with epoxy resin. It doesn't have to be epoxy resin, anything that will bind the powder together and bond with the wood will do (e.g. wood glues). The advantage with most resins is that curing time is shorter, and (depending on the resin) the colour of the metal isn't impacted by the colour of the resin.
If you want a decent metallic appearance, you need to have more than 50% metal content in the final mixture. Ideally this should be has high as 75%, but it requires a resin with quite low viscosity (i.e. quite liquid), and a medium setting time, as you will need to do quite a lot of stirring.
Food colouring dyes have completely different qualities, so I am not sure how they are comparable at all.