Why You Shouldn’t Take Iron And Calcium Together

Why You Shouldn’t Take Iron And Calcium Together

Competitors of one, iron and calcium are not to be taken together. Certain studies show that iron and calcium may compete for the same transporters in the small intestine. This means that presence of both together in the intestine can reduce the uptake of the mineral that is less favoured by the transporter. 

Between iron and calcium, that mineral is iron, the one with low affinity (favoured less). 

What does this mean for you?

  • Take care while choosing a multivitamin. If the two minerals are found in one supplement, you may not get the benefit of iron.
  • If you have separate iron and calcium supplements, make sure you space them out meals. For example, you can take your iron supplements with breakfast and calcium with dinner and vice versa.
  • Do not worry about iron and calcium rich foods colliding in a single meal. The same studies also concluded that the long-term effect through diet may be minimal. Thus, this is only crucial for supplementation. 


Calcium is amongst the other dietary components such as tannins and phytates which inhibit iron absorption. One must ensure the two are supplemented separately.