Why are children allergic to everything these days?

I've read that it's vitamin deficiency (zinc, A and D) and over-exposure to certain substances in the junk food that kids eat. Also, talk to anyone who knows a lot about hazardous materials and he will tell you that a lot of the chemicals that we use every day were not around in the 1950s and earlier. Antibiotics in the water supply may also have a significant role.