system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do we need dietary iron?

If our body is unable to excrete excess iron, and iron from old RBCs are “recycled”, why do we continue to need dietary iron/iron supplements?
gpt
I don't know how efficient the RBC recycling is, but no system is perfect, so we'll always need some miniscule input.

But more importantly, you will lose some blood at some point. Some people more than others, and more regularly, so proper iron intake is particularly important for menstruating women. But suffer a significant enough injury, and you'll also suffer from low iron levels.