Sadly nickle is found in a lot of foods and vitamins.... if just a little bit in each item, but then it adds up over the day week months for a person that is allergic to it.

Ex: Wine which is fine within its self as it does not have nickle present in it, but the equipment used to make the wine has nickle in it, therefore, some is transferred to the wine.... a horror story just waiting to happen to a highly allergic person when they go out to eat and do not know this information or where/how the wine was made.