Looks to me like one each a day. DH eats a couple of handfulsof pumpkin seeds daily for the zinc. Good for prostate too. Quecetin is also high in some foods, dark grapes come to mind.
I am not a fan of mineral or vitamin supplements, I always try to get from foods and herbs, but sometimes a pill may be the best choice. Some info about zinc:
https://www.healthline.com/nutrition/zinc-supplements#types
https://www.medicalnewstoday.com/articles/263176
This one has a lot of general info plus foods high in zinc.
https://www.health.com/nutrition/zinc-supplement
I have no knowledge about which kind of zinc would be better.
Nail biting is a good source of zinc.