Are food intolerances like msg and onion permanent?

Food intolerance: The exact meaning of "food intolerance" is controversial, which is another way of saying "we don't know much about this subject". We know that biological products that contain proteins can trigger the production of allergic antibodies (ige), but many times adverse reactions occur when foods or chemicals are eaten despite the absence of ige. There are very few good studies addressing this topic.

Food Intolerance : Unfortunately they do tend to be permanent although they can fluctuate and sometimes regress in symptoms.