Quote Originally Posted by bounceswoosh
I don't really "get" the whole menstruation/iron problem. I mean, yes, we lose some blood, but it doesn't seem like it's that *much* blood, does it? I think I've lost more blood on some rides than I ever have during my period! Then again, I've always been blessed with light ones.

I get that blood contains iron, but do we really lose enough blood for it to be significant? Or is there some other factor I'm missing?
The idea is, that there are very few ways to get rid of iron. The main way is bleeding, including menstruation. Yeah, you only lose a few ounces of fluid per period, and only part of that is actual blood, but if you didn't menstruate, the iron you consumed would stay with you for a long time. I think heavy sweating also sheds some heavy metal.

So if you're a menstruator OR an endurance athlete, you need to replenish your iron fairly regularly. (If not, iron can build up and as a potent oxidizer it has been thought to contribute to some disease states, so for example sedentary non-menstruators shouldn't probably take it supplementally.) It takes some thinking to make sure to get it from diet (leafy greens, lentils, molasses, cooking in iron pots, fortified foods, red meats) so if you DO have ways to get rid of it (bleeding and sweating) then it shouldn't do any harm to take it in supplement form. But it can cause constipation so watch out for that!