I know there's a technical difference between an allergy and an intolerance, and I'm not interested in going into it yet again right now. How many people have food ingredients that they can not physically tolerate ie. food that makes you physically ill in some way, and not just because you don't like the taste!
My mother can't eat bell peppers - they make it feel like somebody is kicking a football around in her stomach all night long. DH loves them... but for the last year he's become intolerant of them too - they send him running to the bathroom within an hour of eating them. :( So I have to cook without them again. I don't have any problem with peppers, but refined soy products (soy yoghurt, soy cheese, soy milk etc.) give me vicious heartburn and indigestion. I tried using soy instead of dairy for lactose-intolerance but the effects were more unpleasant than the milk so I switched back! I'm mildly lactose-intolerant and have to watch my intake so that it doesn't make me sick, (no jumbo triple-thick milkshakes for me thank you!) but a cup of milk or yoghurt a day and a bit of cheese is fine.