I read what you wrote about whether or not you are intolerant to gluten and dairy as well as corn may be an issue. My husband has gone throught the same thing you're going through, though with the help of a great doctor we figured it out sooner than you have. He was diagnosed with celiac disease in December of 04. He felt great after going on a gluten-free diet for about 6 months. Then he started feeling like crap again. So we looked at everything he was eating and figured out it was dairy. So we cut that out. He again felt good for awhile then again started getting worse. At that point we decided to see an allergist to get some testing done. He had skin testing done, and found out that he's also intolerant to eggs, corn and many, many other things. The whole squash family. Carrots, celery, and in that same family is also all italian herbs. So after we cut those things out he was feeling great. The skin testing also showed some things that he has slight intolerances too. It so easy to think maybe it's not gluten, but I assure you that it's possible to have problems with soooo many things! His doctor asked him to write down his favorite foods, and most of what he wrote he was intolerant to! It's so strange and very frustrating. I completely understand where you're coming from. I definately reccomend getting a referral to a good allergist and getting the skin testing done. The one he had was done on his arm, which is different from the one they do on your back, I'm not sure which is better, but I know the results were very accurate for him. I hope this helps! Corn is a nasty thing to have to cut out, b/c like you said it's in everything. If you need any help with finding vitamins and things like pain relievers and over the counter medicines without corn in them please feel free to email me. I would be happy to help. Let me just tell you one thing, my husband used to be a baker and chef, so we know how hard it is to give up food you love. celiac disease is also on my side of the family as well so I've been familiar with it for a long time. I'll also say the people in my family that have it have multiple other foods that they cannot tolerate, so it's very common. My best advice is to read labels on everything EVERY time you buy it, even if you've done it before. Companies change ingredients all the time, and even the difference between regular and fat free can change the ingredients as well. If you still have problems after cutting corn out, write down what you're eating and how you feel within a half hour after eating it. Write down if you have bloating, if you get tired, stomach cramps, nausea. Any thing that doesn't sound like a "normal" reaction to food. I will tell you my husband has gotten very good at tell if he's eaten something he shouldn't and can usually tell the difference between if it was gluten, corn, dairy, eggs or some other food that is bothering him. Listen to your body!
My email address is SnydDar@aol.com Please feel free to write if you need any help.
Here is a good site for corn allergens. There are lists of ingredients on here that are things made from corn, like you mentioned Xanthan Gum. Get familiar with them and if you have to print the list and bring it with you shopping. There are SO MANY OF THEM! http://www.cornallergens.com/
Also, the gluten free mall has an advanced search for shopping for multiple food intolerances. You can exclude products with the things you don't want in them. But still read the ingredients they have posted for the products because I have caught things like Xanthan Gum getting through even though I clicked no corn in the search. So here is the link for the advanced search.
One other thing is we got a great book used off Amazon called Allergy Cooking With Ease written by Nicolette M. Dumke. In the back it has a whole section on food families. If you find that one thing such as carrotts bother you, you may have to cut out the whole family of that particular food, so that chart is helpful. Take care and I hope this helps!