I just found this in an article on food allergy and intolerances. A different viewpoint perhaps?
Some commentators have argued or theorised that before agricultural societies evolved, those individuals that had more sensitive immune systems were generally better adapted to the natural environment than those who did not, as they were better able to seek out and destroy viruses and other infections in their bodies. Those individuals with antibodies that were less reactive were perhaps less inclined to survive, and more likely to fall victims of Natural Selection. Thus the law of Survival of the Fittest would dictate that more individuals with sensitive immune systems survived in each subsequent generation. The genetic and phenotypic predisposition to mistaking certain protein forms as viruses is from one perspective a good thing. However, with the advent of commecial food production and agriculture, and especially with hybridisation, this characteristic of having a more sensitive immune system then becomes a potential hazard to one's health, if one is not aware of the situation, well informed and that one is consuming proteins that resemble toxic and pathogenic viruses. Thus one could argue that modern society from a Neo-Darwinian perspective encourages the weaker and less robust and punishes the naturally 'stronger', thus creating a genetic disadvantage in the human gene pool, which as discussed above, arguably affects large segments of the population, who may be more prone to developing other allergies, asthma or even autoimmune diseases.