We've recently found out that our son is allergic to milk, soy, and eggs. The doc that we see said that the bible of allergies is http://www.foodallergy.org. And here http://foodallergy.org/allergens.html#soy it says that for people allergic to soy it is ok to have soybean oil (certain kinds) and soy lecithin. It's usually the soy protein that people are allergic to. But check with your doc.
I would definitly do some liver cleanses, and a Bowel Cleanse (drnatura.com)