What effects does eating pottery cause?

Anemia: Some people who have iron deficiency anemia have a desire to chew on ice or ceramic pottery. You should see your doctor to be checked for that or any other problems.

Can't be good.: Not sure i understand this correctly, but pottery and glazes should be relatively inert and non toxic. However, the mechanical effects of ingestion such as lacerations, potential dmage to teeth and obstruction or laceration of the GI tract seem enough to keep most people from chewing their china.