Vitamins are things your body needs op, if you have too little of them you get sick, if you have too many of them you get sick. You need to contain. Supplements are shit, do not EVER try them out, theyre not FDA approved and theyre the equivallent of sawdust and filler.
Zinc and Iron are metals that your body physically needs, you can get them from red meats and chick peas. There is no vitamin pills are necessary if you have a deficiency, obviously, but unless its a condition or a disease you can easily get them by a change of diet. Those people who swear by them are most likely suffering from the placebo effect of the drug, nothing else. A 'miracle cure' is just that, a miracle, and i doubt god is going to spend his time making pills for idiots to buy