I was thinking of adding zinc into my supplement regime. The one I have has the following ingredients: Zinc (as amino acid chelate 125 mg) - 25mg Manganese (as amino acid chelate 20 mg) - 2 mg Vitamin B6 - 10mg How much of this zinc should I take each day? It also says on the bottle "Contains zinc which may be dangerous if taken in large amounts or for long periods" How much would a "large amount" be? And how long would a "long period" be? Thanks!