Then there are always those who are medically advised not to use cast iron - the strongest dietary restriction for iron overload disease. Which, BTW, is more common than generally thought and often mistreated as anemia....so if you're tired, truly fatigued with unusual unaccounted for health symptoms, get it checked out. I believe the correct test is Iron saturation - not the normal iron {Fe} drawn on a common chemistry panel.
[Okay, off my kitchen stool...hubby has it and it's a very bad thing - so I try to spread the word.]