"Going back to not washing the roots and leaving a little soil on them, it is for your own good. A good bit of immunity comes from the soil, it starts as soon as you are born. Your fingers touch something, and you put them in your mouth. A little dirt at first, and more as you grow older and start crawling. Then everything you touch goes in the mouth. When children go outside to play and when they come in, they are the dirtiest around the mouth and hand. The hands go in their mouths no matter how dirty they are. Many diseases and bacteria live in the ground, but they don't seem to cause any trouble but it does build up the immune system. Some animals can't live if they can't eat a certain amount of soil" http://www.rense.com/general74/dandi.htm