I have actually listened to someone who looked deep into zinc and how much to take. 100 mg per day if you feel yourself getting sick. 30 mg per day on a regular basis and you should be bullet proof.

You shouldn't take more than 30 mg long term since it will damage your kidneys.

Vitamin D. I spoke directly with a doctor...a trustworthy one...he said 10,000 IU during the summer and 15,000 IU in the winter. Even people that get sun every day can be low in vitamin d. Unless you are exposing "fresh skin" daily you can not absorb enough.