Question: Why are we allergic to some foods?

Pete Etchells answered on 26 Apr 2012:

I don’t know exactly why, but it’s basically because our immune systems over-react to certain things in certain food, which is what causes an allergic response. You might be allergic to some things because of you genes (so you might have inherited the allergy from your mum or dad), but environmental factors also play a part. For example, if you ate the same sorts of things for most of your life, then suddenly changed your diet to include something new, your immune system might not react that well to the new food, and cause an allergic response.