you should call the manufacturer and ask the company why. supplement companies are not regulated like drugs are so be careful and make sure your voice is heard. zinc intakes above 150 mg have been associated with adverse effects such as low copper status and a lowered immune response. no more than 40mg in supplements is recommended. read this for more on zinc supplementation.
why do some vitamins contain too much zinc. preservision areds has 348 mg. and the max. daily is 40 mg. ! why would they put that much in there. now i'm afraid to take it paid for it and opened it can't return it.