Most people are aware of the importance of iron but less aware of the things associated with it and where theoretically problematic sources might be prowling in our diet. Here’s how our bodies uses and loses Iron.
Iron helps deliver oxygen from our lungs to our tissues. The oxygen we breathe into our lungs hitches a ride from hemoglobin, the iron-rich protein inside our red blood cells. Hemoglobin and iron “carpool” together, picking up oxygen and dropping it off at its destination (tissue) and scooping up carbon dioxide on the way back to the lungs to be exhaled.
Our bodies are also extremely frugal with iron. We recycle and reprocess the iron from old red blood cells and have devices in place that change any excess iron in our blood to ferritin, the storage form of iron we can use if our levels ever drop too low.
Women in their reproductive years require a lot more iron than men. Menstruating women need to replace the iron they lose every month to prevent iron-deficiency anemia. Pregnant women also require more iron to support increased blood volume and the nutrient requirements for a growing baby.
Heme Iron vs. Non-Heme Iron
There are two types of iron: heme iron, and non-heme iron. Heme iron is connected to hemoglobin and myoglobin, which is why it’s only found in animal protein like meat, fish, eggs, and poultry.
Non-heme iron is found in both animal and plant foods. The non-heme iron in plants is bound to phytates, oxalates, and other “anti-nutrients” that inhibit its absorption. That’s one reason why iron is a nutrient of concern for vegetarians and vegans—they must make sure they’re maximizing iron absorption from iron-rich plants like beans, dark chocolate, lentils, spinach, pistachios, and pumpkin seeds (see below for my recommendations on accomplishing this in the best way).
Unfortunately, for the average American, the primary sources of non-heme iron come from refined flour and fortified grains, which can be potentially an issue if consumed too much.