Why does everything you intake into your body show up in your hair?

Well, it is my understanding that whatever you bring into your body will be absorbed on a cellular level, not only by your hair, but by your entire body. Your skin and your blood will absorb chemicals and nutrients and vitamins just like your hair. However, you shed skin. Your blood is cleaned regularly by your liver. Your liver is like the garbageman of your body: it keeps it clean. Your hair, however, is only living tissue at the very base of each strand of hair. The hair follicle itself is actually dead tissue, so there is no cleaning going on. Everything that is absorbed into your body eventually finds its way to your hair. Think of it as a tiny tiny stain in your hair that doesn't get cleaned. So...it's not that your hair is the only part of your body absorbing things. It just doesn't have a cleaning system set up, so whatever it absorbs is there permanently. That's my guess.