The short n curly version is that all stainless steel cookware leaches nickel and chromium into your food, particularly when the food is acidic.
Particularly when the cookware is new. Might want to boil vinegar in new SS pots before use, or cook the first 6 meals for other people.
Not covered by the article, but cast iron has the same issue with acidic foods, except they leach iron, which can be a problem.
Moral of the story, be careful cooking acidic shit.