According to Dr William E Walsh, in his book Food Allergies : The Complete Guide to... there are 2 types of allergies. The allergies against food proteins and the allergies against food chemicals.

Allergies against chemicals

This includes allergies against

Monosodium Glutamate (MSG)

Acidic foods

Low calorie sweeteners

Refined Sugar

As a doctor, he says he is aware it is against common medical teachings to say that these could cause allergies, but by listening to his patients and eliminating suspected food from their diets, he came to the above conclusion that the foods containing MSG, acidic foods, low calorie sweeteners and refined sugar could cause allergies in some individuals. He also suffers from allergy to MSG and writes about his own experiences as well.

Allergies against Proteins

This includes allergy against the proteins in

	peanuts
	shrimp
	milk
	wheat
	corn

Certain antibodies, the IgE antibodies react with specific proteins which end up leading to allergic symptoms. Read How eczema occurs for details.

Symptoms

Be aware that the allergy symptoms could occur immediately, be severe or even life threatening making it more obvious. They could alternatively be delayed, accumulated or mild and hard to identify.

The symptoms of food allergy include

	migraine headaches
	hives and angioedema
	asthma
	swelling in the respiratory tract
	swelling in the sinuses
	swelling in the chest
	swelling in the joints
	abdominal cramps and diarrhea
	contact dermatitis or eczema

Exercise-induced anaphylaxis is mentioned in his book Food Allergies : The Complete Guide to... In this case, the victim suffers the allergic symptoms after exercise. If he just eats the food and lazes around, nothing happens. If he eats the food and exercises, say 4 hours later, he gets the allergic reaction. It could be mild, like just hives. It could be serious and completely block your breathing. Worst of all, it is hard to identify.

How allergies start

You are born with your food allergy. It might bother you as an infant. It might only bother you as an adult. Basically, you immune system keeps it in check. As you grow older, your immune system weakens. Your allergy surfaces. Also accumulated exposure to the allergen or even other allergens have the combined effect of overpowering your immune system so the allergy symptoms surface. Viral infections can weaken your immune system so you start getting the allergy symptoms. Something like a cold that started off as a viral infection, but never ended after that.

At the end of the day, it is up to you to play detective to find out what is causing your allergies. Blood tests are useful but some allergies can go undetected in blood tests. Seek your doctor's advice if you plan to avoid certain foods you suspect you are allergic to. If you suffer severe allergies, please see a doctor.

For relief, check out these Allergy supplements