Many of my friends complain that they feel drained, especially when they are having their periods. They say that they lack energy, have trouble sleeping and difficulty concentrating—all symptoms of anemia, which can be caused by an iron deficiency. And although I’m no doctor, I make the same recommendation to everyone: Start taking iron. I’ve been supplementing with iron daily for 15 years now, ever since I was first pregnant. And although menstruation is not exactly an enjoyable experience, I no longer get that totally-drained-can’t-lift-my-head kind of feeling that I had before I started taking it. But there’s one little hitch in my prescription: Up until recently, I was getting…