Thank you for asking about Sissy.
When a dog eats dirt, it may mean nothing. However, the most common finding is that the dog is anemic (has a low red blood cell count).
This is usually not due to a mineral deficiency, but can be caused by many things: eating rat poison, tick borne diseases, other types of infections, a type of anemic called AIHA, and others.
When I hear of a dog eating dirt, I usually check the red blood cell count. If it is low, I try to find the cause.
Just adding minerals to the diet might help, but it probably won't if the dog is actually anemic.
However, sometimes dogs just eat dirt because they like it. If Sissy is getting a good commercial dog food, she should be getting all the minerals she needs.
she has always been on all natural food from California Natural, Fromm and recently Canidae