DS is allergic to some tree nuts, we started solids at 6 months. You have to be careful with trying to feed your baby foods to overcome an allergy. Do so with medical advisement. I have heard of many stories of where parents thought they could raise the immunity by slowly giving the food only to cause a severe allergy. Then the baby was not be able to eat it for a really long time, if at all, because of it.

DS was allergic to egg when he was a baby, we didn't give it as per medical advice for a long time and now he can have it.