[blagie]

Peanuts were plentiful 100 years ago, and certainly 50 years ago when allergy rates were much lower.

There are also striking geographic differences in allergy rates as well between the US and less developed countries (even within genetically identical populations).

Anecdotally, I also know a bunch of people who developed allergies (not peanut / treenut, but seasonal) a few years after they moved to the US.

It looks like there's something environmental going on. I just don't know what yet.