It seems like in this case the addition of the dirt might add some iron to their diet.

> Mehravari confirms that gelak “contains several different iron chemicals. It is possible that for those who are iron-deficient, eating the sauce will help increase the required level of iron in the body.”

I remember reading another article years ago about scientists trying to give some people a "lucky" iron fish to add to their pots while cooking rice to add extra iron, since the cookware was no long iron based.