Is the calcium from Mom's bowl of cereal and milk inhibiting the absorption of her iron supplement?

A fellow caregiver asked...


My mom has been taking an iron supplement with contains Vitamin C (for better absorption) for a couple years now, due to a low hemoglobin level. She also take a multi-vitamin at night that includes calcium but takes her iron supplement in the morning since she had heard that calcium can inhibit the absorption of iron. However, I just realized that her morning routine almost always includes eating a bowl of cereal with milk. Now I'm wondering if this is also inhibiting the absorption of the iron supplement. If so, which is the "lesser of two evils"- taking the iron supplement at night with my multivitamin or taking it in the morning shortly before she eats her bowl of cereal.

I'm sure the best answer is to wait two hours after eating to take the supplement but I feel pretty certain she will not remember to take it if it's not part of her nightly or morning medicine routine.

Expert Answer

Jennifer Serafin, N.P. is a registered nurse and geriatric nurse practitioner at the Jewish Homes for the Aged in San Francisco.

Iron deficiency anemia (IDA) develops when the dietary iron intake does not meet the body's demand for iron. IDA can be associated with low dietary intake of iron, inadequate absorption of iron, or loss of iron from something like bleeding. Post-menopausal women usually do not lose iron through blood loss as younger women do. Therefore, they have a lower risk of iron deficiency.

There is some literature about iron interacting with calcium, so it is possible that this could happen. If you are really concerned about the iron interacting with her morning milk intake, perhaps she can try taking the vitamin at lunch instead.

What I would recommend is that you ask her health care provider to check her current iron level. If she has been on iron supplements for a "couple of years", her iron levels should be normal by this time. If her iron level is low, she may not be absorbing the iron, or she may have blood loss or some other issue. This would need more investigation by her health care provider. If her iron level is normal, then perhaps she can stop taking the iron supplements all together, as her iron stores are adequate. At this point her bloodwork can be monitored closely to make sure she remains stable.

Good luck!