It's pretty difficult to overdose on vitamin D but I think between 3000 and 6000 IUs I've seen - I live in Canada so not much vitamin D from the sun these days.

Zinc is more problematic as it's more fat soluble/stays in the system longer, and zinc poisoning only occurs through supplementation. The best sources of naturally occuring zinc is eating oysters as probably 3oz of oysters is all the zinc you need for a week.

It's pretty difficult to overdose on vitamin D but I think between 3000 and 6000 ICUs I've seen - I live in Canada so not much vitamin D from the sun these days.

Zinc is more problematic as it's more fat soluble/stays in the system longer, and zinc poisoning only occurs through supplementation. The best sources of naturally occuring zinc is eating oysters as probably 3oz of oysters is all the zinc you need for a week.