This mineral is required by the prostate gland roughly ten (10) times more than any other organ in the body. Studies have confirmed that supplementation with this mineral reduces enlargement of the prostate and relieves symptoms of benign prostate hypertrophy (BPH), thus explaining its recommendation for both prevention and treatment of this condition. In addition, this mineral is found in relatively high concentrations in the retina, where it plays an integral role in maintaining normal eye function. In fact, low dietary levels of this mineral appear to be related to an increased risk for developing age-related macular degeneration (AMD). Furthermore, this mineral is necessary for fertility and reproduction, immune system health, insulin function, thyroid hormone metabolism, bone strength and growth, night vision, taste and appetite, and virtually every enzymatic reaction that occurs in the brain and central nervous system. What is this mineral?