Iron absorption in non-haem is influenced by calcium, zinc and phytates, but how does this model refer to the reality?

Iron in non-haem is influenced by calcium and phytates, so they would not be absorbed or are in competition for divalent metal transporter. But how many DMT's are there in reality? How is this model translated to the reality? Can there be 50% absorbtion, or is always zinc prefered over iron