I'm not sure about actual research (I'll have a look) but the idea of avoiding the allergen is so the immune system can basically 'reboot' itself. When we have an immune reaction to something, the body makes 'memory cells' so in the event we are exposed again, an immune response can be mounted quicker. This is why when someone is severely allergic to something, the response gets worse upon subsequent reactions.<br><br>
If you can keep the allergen completely away for a long enough stretch of time, you can actually make the immune system forget that it didn't like the allergen. Most of the time, the way our children become sensitized is through their immature gut. Things get in that normally would not. If when you reintroduce the food, the gut is more mature and less leaky, the allergen will be broken down much more before it reaches the blood stream and isn't recognizable to the immune system as foriegn.<br><br>
I hope that sounds somewhat coherent <img alt="" class="inlineimg" src="http://www.mothering.com/discussions/images/smilies/smile.gif" style="border:0px solid;" title="smile">.