Lab Cat

20 Feb 2008

Self Diagnosing Food Allergies

Filed under: Food, Health — Tags: — Cat @ 10:29 am

Continuing discussion on food allergies, there is concern amongst dietitians in Australia that people are self-diagnosing themselves as having food allergies and intolerances. While avoiding a food items is not the issues, there is a problem:

The number of adults being diagnosed with food allergies has remained constant, but the number of people incorrectly self-diagnosing food allergies and intolerances has skyrocketed,’ Ms Graham said.

She said a problem with self-diagnosis was the risk of missing an underlying health problem.

[link]

Not mentioned in the article is that fact that if wheat or dairy are being excluded from the diet, the diet could missing essential nutrients and sufficient energy, especially for children.

The bottom line, as always, is if you think you may have an allergy visit your doctor and get tested.

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8 Feb 2008

Food Allergies

Filed under: Basic Concepts, Food, Health — Tags: — Cat @ 8:00 am

Professor Richard E. Goodman, from Nebraska-Lincoln visited the local Institute of Food Technologists’ (IFT) section and gave a very interesting talk about food allergies. He is an active member of FARRP (Food Allergy Resource and Research Group), which is a resource for the food industry to test for and research known and potential allergens.

In this post, I tried to summarize the bits I remember but as I did not take notes, I found this information on the web. Thus, if anything is wrong, it is my fault, not Dr Goodman’s.

Food allergy is an adverse clinical reaction to food due to any type of abnormal immune response to food protein.

There are two mechanisms by which a food allergy can trigger the immune system. The first is IgE-mediated:

ige1cell

IgE-mediated food allergies are mostly immediate reactions, occurring within in minutes to hours of ingestions. The IgE response is the cause of anaphylactic shock, which is the cause of death after eating peanuts and bee stings. In this case, the allergic response is so extreme that it causes the air passages to swell; blood pressure drops leading to the inability to breathe and eventually, if not treated, it is fatal.

The second mechanism, which is mentioned by Dr Goodman and on the Act Against Allergy website, is Non-IgE mediated and involves the interaction of T-cells with the allergen and the part of the body where it is located.

Non-IgE mediated food allergies are usually delayed, taking 24 -48 h for a reaction.

Key symptoms of food allergies include hives, hoarse voice and asthma. In a severe reaction, there may be low blood pressure and blocked airways. Other symptoms that may occur include abdominal pain, angioedema (swelling, especially of the eyelids, face, lips, and tongue), diarrhea, difficulty swallowing, light-headedness or fainting, nasal congestion, nausea, and oral allergy syndrome (OAS). Symptoms of OAS are:

  • Itchy lips, tongue, and throat
  • Swollen lips (sometimes)

This last interested me. I have already discussed the problems I have when drink alcoholic beverages, especially beer, but I also have OAS in response to fennel and ginger*.

Common food allergens seem to vary depending on where you live. In the US, since January 2006

…the Food and Drug Administration (FDA) is requiring food labels to clearly state if food products contain any ingredients that contain protein derived from the eight major allergenic foods. As a result of the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA), manufacturers are required to identify in plain English the presence of ingredients that contain protein derived from milk**, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, or soybeans in the list of ingredients or to say “contains” followed by name of the source of the food allergen after or adjacent to the list of ingredients.

source

[highlights mine]

Peanuts, treenuts and shellfish are the most common foods to trigger anaphylactic shock.
In Europe, the EU directive since November 2005 states that:

The 13 main food allergens must be listed: gluten-containing cereals, shellfish, fish, egg, peanut, soy, milk, tree nuts, celery, mustard, sesame seed, lupine and mollusks. Products derived from these allergens must be named without exception if used as an ingredient. In addition, sulfite must be listed if more than 10mg/kg is used.

Source

Currently, the only way to prevent an allergic response to a food item is avoidance. Ephedrine can be used, via an EpiPen to stop an anaphylaxis response, but will not prevent the reaction occurring again.

More food allergy links:

MedicineNet

FamilyDoc: Just the Facts

emedicineexcerpt

 

There is also a consumer advocacy and support group: The Food Allergy and Anaphylaxis Network (FAAN).

Footnotes

*I have another response to ginger in that it irritates my urethra (the passage from the bladder out) and so when I eat or drink anything gingery (ginger beer anyone), I have to remember to drink lots of water to reduce this irritation. I used to get, I thought, a lot of cystitis or infections in my urethra. Finally, I noticed that “infections” were linked to the day after when I went out for a curry, which was fairly frequent as a graduate student. Sigh. I probably should be grateful that curryhouses are not so common here in the US.

**Fortunately all the websites I found differentiate between food intolerance and food allergy. A food intolerance is when you cannot digest something properly, such as lactose. This means that the ingredient remains intact until the colonic microflora get hold of it. Then the gut bugs have a party. Seriously. A serious party.

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