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.

If there's a real deficiency, it should be managed with blood tests.

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.)

Blood tests can't measure concentrations in other tissues.

Have you gotten a colonoscopy?

Yeah I'm not going to go into everything but this was based on lab work.

Blood tests are often misleading, not showing tissue deficiencies. For those there might be 1-2 labs in the world that can do them depending on the type of deficiency.