Want to know what you're allergic to? IgE, not IgG, should be measured

"Your child has a severe allergy, so don't eat eggs, milk, fresh, peanuts, hairy fruits ...... and so on." Physicians have always warned parents to avoid allergy-prone foods if they want their children to alleviate allergy symptoms.

But if I were a parent, I'd be worried about what I could eat.

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Food allergy is actually very complex and has been the subject of much attention in the field of allergy around the world in the past few years. Some scholars say that it is the second great leap forward after asthma because there are still so many issues that need to be explored and that are relevant to our lives.

Commonly heard food allergens include milk, eggs, peanuts, seafood, and nuts. However, cooked and raw foods can also produce very different allergic reactions.

An allergic symptom or reaction cannot be called a food allergy

There are some cases that are often mistaken for food allergies.

Some people get diarrhea when they drink milk, but they are actually lactose intolerant to milk, that is, they can't metabolize lactose, not allergic to milk. The intolerance to a certain food has nothing to do with the body's immune response, most of which affects the gastrointestinal tract and causes symptoms such as stomach pain, nausea, vomiting and diarrhea, which can't be considered a food allergy.

Eating food contaminated with bacteria or microorganisms, such as salad or milk, that causes abdominal pain and diarrhea is food poisoning, not a food allergy. Some people eat seafood once and produce skin allergy symptoms like hives, also not necessarily allergic to seafood, it may be because it just happened that the batch of ingredients in the process of processing of freezing preservation is not handled properly, and the production of too much "histamine" (allergic reaction occurs when the body's cells secrete a large number of substances), eat too much foreign food containing high levels of histamine, will also produce allergic symptoms, but does not mean that the seafood allergy.

There are also some food additives that are used to add flavor to food, which can cause similar allergy-inducing symptoms when consumed in excess, such as sulfites for preserving food and monosodium glutamate (MSG), which is commonly used in stir-frying.

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Want to know what you're allergic to? IgE, not IgG

To test whether you are allergic to a particular food, you need to take a blood test for food allergens, in addition to the traditional skin test. It's a blood test, but it's important to keep your eyes peeled to see what kind of antibodies are being measured.

The so-called allergic reaction is when the body's immune system produces a large amount of immunoglobulin antibody E (IgE) to an allergen, causing subsequent skin, respiratory, and nose symptoms. However, there are many tests on the market that measure immunoglobulin antibody G (IgG), and the result is that almost all foods are allergic to it, and the report card is full of red, so you can't eat anything, and you don't dare to eat anything! I can't eat anything, I don't know what to do with my life.

The IgG antibody test does not represent a food allergy, which is clearly written in the textbook.

A while ago, I went to a meeting in Beijing, a Singaporean scholar also suggested not to use IgG antibodies to do the interpretation of food allergy testing, I thought it was just a phenomenon in Taiwan, but other countries also have such a myth. Therefore, the blood test allergens, is to measure the concentration of IgE antibodies in the blood, rather than IgG concentration.

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Chronic food allergy?

It is not uncommon to see so-called "chronic food allergies" in newspapers and magazines, with symptoms such as abdominal pain, bloating, headaches, frequent colds and flu, insomnia, fatigue, muscle aches, anxiety, depression, and even hyperactivity and lack of concentration, among other symptoms of "civilization disease.

If you use google to search for "chronic food allergy", you can find a lot of information, and it mentions that it is related to the IgG that the body produces in response to food. However, there are no scientific journals in the medical literature that mention chronic food allergies, which naturally do not cause these symptoms and do not require dietary restrictions.

In addition to knowing that you are allergic to a certain food, reading the label of the food you are allergic to is also a way to prevent it. However, the FDA's "Food Allergen Labeling Requirements" will not be officially on the road until July next year (2015), including six categories, shrimp, crab, peanuts, milk, eggs, mangoes and their products. The company is required to add a note on the packaging of these foods, in the format of "This product contains ○○, not suitable for its allergy sufferers to eat".

Each food has different characteristics and is subjected to different temperatures, and each person's adaptation or tolerance is different. Therefore, it is important not to generalize, and not to interpret an allergic reaction to a certain food as an inability to eat it or to eat less of it, and not to neglect nutritional intake and balance because of the fear of allergic reaction to the food.

<This column reflects the opinions of experts and does not represent the position of this organization>