There's an interesting new study out saying 3.6% of all Americans have a "food allergy or intolerance," with the most prevalent being shellfish!

{As a side note, I quibble a bit with the coverage here because they "define allergy as any adverse reaction" but only list the ones most classically associated with allergy (including hives & anaphylaxis) and not ones like G/I reactions that are associated with intolerances. Thus, it seems likely to me that actually the number of "food allergies AND intolerances" may well be far higher than 3.6% - but anyway, here it is!}