This is a weird video to see after one of my son's doctors told me I should supplement him with zinc. Of course I'm following dosage recommendations.
Growing up and recently, I've been anemic (iron deficient) without any obvious medical cause. That requires supplementation with an unusual amount of iron.
Also, I'm vitamin A deficient at baseline and have to take large amounts, around 15k IU/day, to stay within the "normal" range. (50% above ordinary UL.)