Zinc - is an essential mineral that is a component of more than 300 enzymes needed to repair wounds, maintain fertility in adults and growth in children, synthesize protein, help cells reproduce, preserve vision, boost immunity, protect against free-radical damage and more. Zinc deficiency can lower the immune system, cause poor vision and reduce wound healing time. Good sources of zinc include oysters, meat, eggs, seafood, black-eyed peas tofu and wheat germ.