Quick Tip: Calcium Interferes with Iron Absorption
If you take a multivitamin containing iron (or an iron supplement) and you take a calcium supplement, it’s a good idea to take them at different times. High doses of calcium, especially calcium carbonate, the form found in most supplements, can block the absorption of iron.
Try taking your multivitamin with breakfast and your calcium supplement at dinner or before bed. Taking calcium late in the day can also help you relax and fall asleep more easily.