All About Fish, Shellfish Allergies
Why Me?
So why is it that a food you’ve always been able to tolerate suddenly starts wreaking havoc? There is no firm answer, but scientists theorize that it could have something to do with the fact that the main allergen in shellfish, the muscle protein tropomyosin, is very similar to the tropomyosin found in dust mites and cockroaches, which are some of the most allergenic pests.
So exposure to those insect proteins might actually increase a person’s odds of developing a seafood allergy. (This would also explain why studies in which orthodox Jews, who have never eaten shellfish, end up with positive results for shellfish allergy in medical tests.)
Another hypothesis is that many adults eat seafood on occasion rather than regularly, and that may affect their tolerance. In other words, the immune system may in effect forget that the food is not a problem, and may instead treat it like a harmful invader.
Pass the Caviar
It’s important to note that the key allergens in fish and shellfish are unrelated, so people who can’t eat salmon might be just fine with crab, and someone who can’t tolerate even the tiniest amounts of shrimp may be able to eat whole helpings of fresh cod.
To further complicate matters, some people only react to very specific foods: so they may be able to eat crab but not oysters, or they may be allergic to the roe (eggs) of the fish, but not to its meat. Others who cannot tolerate fresh tuna or salmon may be just fine with the same fish canned, which has led some researchers to believe that the method of food preparation could have something to do with seafood’s allergenicity.
Seafood Allergy Myths
There is some confusion about the safety of both fish oils and iodine for people with shellfish allergy.
Fish oils are popular as nutritional supplements, because they are very rich in essential omega-3 fatty acids – but are they safe for people with allergies? According to Health Canada, most of the oils are so highly refined that they no longer contain the allergenic protein, and they should be safe to consume.
However, if you have a seafood allergy, it’s important to discuss any fish products with your allergist before trying them out; it may also be a good idea to contact the company and ask them about the processes they use.
Because many types of shellfish are rich in iodine, some shellfish-allergic people are told that they must avoid iodine – a common ingredient in everything from table salt to x-ray dyes. This is incorrect: the allergen in shellfish is in the flesh of the food, and not in the iodine, so iodine should be safe to consume. (Some people cannot tolerate iodine, but this is a separate issue.)
BlueHawaii
I’m one of those adults who developed it in my 40′s. I was getting mild reactions way prior to my final episode. But it was so sporadic, that I just thought I ate something bad or I just over-ate. My body was telling me something but I wasn’t listening. Since I only ate seafood outside of my home, my reactions were inconsistent. One time I was okay, the next time not and I frequented the same restaurants. So since there was so much inconsistencies I never figured it out. My anaphylatic reaction came one night when I had a fabulous crab dinner at an upscale restaurant. An hour later I had this weird sensation of my hands and feet burning, then itching intensely but it was itchy inside of them, not outside like an insect bite. I didn’t know it but at that time my body was reacting as the allergen was coursing through the various body parts. Then my face felt hot but no hives, then I started coughing, my first asthma attack as I labored to draw air into my lungs. I then had a hard time breathing and then my voice dropped to a whisper. My date looked on in alarm (first date too). We finally found a water cooler and drinking the water helped. After another hour I was finally okay. A week later at a routine doc exam I brought it up to my doc who diagnosed me and told me I could’ve died that night. *sigh* That was the end of my life long affair with shrimp and crab. What makes it hard is that Hawaii, due to the big Asian population, has a LOT of Asian restaurants. I had to ban myself from Chinese food because they add oyster sauce to nearly everything. Japanese food sauces also have oyster or scallop added. Until Panda Express came along I have not eaten Chinese food for over 10 years. Panda Express does not use any oyster sauce to their food, thank God. My strong craving for shrimp took years to go away.
Sometimes I would imagine eating shrimp once again. Now I no longer do. But eating any type of Asian food is like “danger danger Will Robinson”. I found out that Vietnamese and Thai food is mostly free of seafood flavorings. Of course it’s not Chinese or Japanese but at least it’s just as good. I did accidently eat shrimp once in a Chinese dim sum that I didn’t know used shrimp (thought it was pork), but I didn’t react. Also ate a clam accidently in a chowder and again I didn’t react. I suspect my stress levels may be related to a reaction, but no way will I test that theory.
I did see an allergist and found out that I’m also allergic to dust mites and roaches, like the article says. Here in Hawaii, due to our warm weather, we are besieged with roaches always. Later on I reacted to pistachos so no longer eat that along with cashews. But I’m fine with all the other tree nuts and peanuts. With all the Asian fusion type foods and chefs adding different ingredients when I eat out, it’s like 20 questions I play with the waitress. Even a simple fried rice is made with oyster sauce these days – a hugely popular breakfast here. It’s incredibly frustrating to live here with so much seafood meals and not be able to eat it. I am also embarrassed, I went once to PF Chang’s with the company staff and I had to have a special dish made for me without oyster sauce; the rest of the team ate stuff off their menu a variety of dishes. Me, I only had one. I tried to make it at home, but Chinese food has to be made in those huge woks at a high heat, not something made at home it just doesn’t come close. Or having to eat shrimp-free tempura. *sigh* It plain sucks.