IGHE and Allergy: Because: (1) allergenicity depends upon the dietary choices of parasitizing acarians, and (2) the ancestors of synanthropic acarians that now cause allergy were carnivorous, our mammalian ancestors might have been at risk for IgE-mediated red meat allergy had they not themselves expressed galactose-α-1,3-galactose (α-gal) (125).