Well, I went to Vitacost, where I get my supplements, and looked up “dirt.” It asked me if I meant “diet”?
So I looked up “clay.” And I did find one diet supplement, although there must be a cheaper way of eating dirt, I would think. But I hesitate to just dig it up, because I suppose you need the right kind of clay.
http://www.vitacost.com/Redmond-RealSalt-Clay
Then there’s Dead Sea Mud, but that’s apparently used as a facial mask, to make your skin look good.
http://www.vitacost.com/Sea-Minerals-Mud-from-The-Dead-Sea/?bnPageBox=pp_alsoviewed&vbnpid=61488