I can only say that our Mary's been dumping nickel for four months (this last round it was double the highest number on the reference range). We have seen an improvement with her behaviorally as well as cognitively.
I can't say for sure where it came from (I have very high nickel according to hair analysis) and we used stainless steel cookware for years. I'm now using enamel coated cast iron.
Becky Simpson
Maryland