Hello Shelly
I can't speak to what you're asking regarding zinc/iron... but vitamins and minerals are typically pretty safe... iron in babies could be an issue of overdose... but things like minerals found in food are typically safe so long as the dosage matches what one would generally be able to eat... meaning if you had 6 oysters, you're getting almost 35mg of zinc... never mind the rest of the food that day though most others are low in zinc. So if you started eating oysters everyday, would he still see it as deadly? Maybe the dinner bill but I would say no... further more, I've taken 100mgs of zinc a day at times in the past, I was pretty healthy but that would've been 18 oysters, which I couldn't do in 1 sitting but you get my drift... people are not dying from oysters (mercury poisoning not included)
Manganese is a little harder to come by... pineapple, peanuts & pecans for example have low amounts.... but again, you can get it with enough peanuts and barring an allergy, you'd reach 10mang in a day...
That's just my opinion though I would track any absorption contraindications (if I'm using it right) ... for example, taking X with Y is counter productive because they fight for absorption so split that into the day. Or after taking X, it lowers Y to include that. Calcium / magnesium is an example of this...
Obviously do what feels best but these dosages are generally low and acceptable... I personally don't know what your full diagnosis is but asking a doctor if a multivitamin that contains zinc and mang could ease all concern as well... I'm betting he'll say definitely
