Iodine in shellfish does not cause allergies.

There is a well established myth that fish and shellfish allergy is linked to the iodine content of fish and that iodine allergy and shellfish allergy are interrelated.  This is untrue.

 Shellfish such as shrimp, prawn, crab and lobster are crustaceans (crawl around) and have a protein in their flesh that can cause allergies, they contain too little iodine to cause any problems. Mussels, clams and squid are members of the mollusc (snail) family and a protein in their flesh can also cause food allergies, but they do not contain enough iodine to be a problem.  Shellfish can ingest a nasty flagellate organism which causes food poison and a toxic reaction with vomiting, diarrhoea and flushing (this is not an allergy). 

Iodine allergy is unrealated to shellfish but iodine can cause a local skin reaction when exposed (contact dermatitis) or a more severe anaphylactic reaction when radiocontrast dye is injected into a vein during invasive radiological examinations such as an isotope scan or angiogram used for investigation of kidney, heart, bone and brain conditions.  Many doctors dont realise this seafood myth and will still ask if you are allergic to shellfish before giving radiocontrast.

 The common joint supplement Glucosamine taken to help arthritis symptoms, although processed from shellfish extract (crab, shrimp and lobster shells), can safely be taken by people with shellfish allergies according to the Mayo Clinic in the USA.


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2 Responses to “Iodine in shellfish does not cause allergies.”

  1. Jack Morin says:

    I recently had a severe allergic reaction which required a hospital visit. The only out of the ordinary thing that I had eaten recently was a new brand of shrimp. My only known allergy is to iodine which was determined several years ago when I underwent testing that required the injection of radio contrast dye.

    I am 67 years of age and have never had any other sort of allergic reaction.

    It has yet to be determined unconditionally whether or not the shrimp was the cause, but it seems to make sense. Because of the potential for shellfish to contain high quantities of iodine, your statement that the shellfish could not be the problem, was questionable from my point of view.

    The fact that my only known allergy is to iodine and the only thing I had consumed that could have accounted for the reaction, was the shrimp, the conclusion is, in my opinion (and it is only an opinion – although it was shared by the doctor that treated me for the allergic reaction) that the shrimp was most likely the cause.

    Would you comment, please.

  2. Joan Kroll says:

    I have just become violently ill, and have traced it back to seafood/fish. This
    is diarrhea and cramps, not stomach. I am a vegetarian, what can I eat? I have eaten fish & seafood my entire life.

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