1) Increase in strength & performance
Zinc has a lot to do with hormone production. Mainly, it is responsible for quickly releasing testosterone, producing natural GH and increases protein synthesis especially through IGF-1 (insulin growth-like factor 1). 2) Supports male & female fertility
In males, zinc supports the prostate, which can eventually become a problem for men, by helping to produce enough testosterone to keep it working properly. In women it supports healthy egg production and keeps excess oestrogen (that will increase body fat storage) in check.
3) Increase immunity
Zinc increases T cell production. T cells fight off dangerous bacteria, viruses, etc.
4) Natural antioxidant
Zinc counters the effects of high iron levels and fights off free radicals, which do damage to the cells of the body.
5) Increase in cardio health
Helps to maintain healthy endothelium (cells that line the blood vessels) which have a lot to do with circulation. Adequate levels of will help prevent unhealthy cholesterol levels.
Many more benefits exist.
For best results take at least 50mg of zinc per day and, yes, ignore the bullshit recommendation of 15mg per day.