Image Source: www.shutterstock.com

As of 2018, less than 1% of global population has fish allergy. It is more common in countries with higher fish consumption such as the Philippines which has a higher prevalence of 2.29% as compared to other countries. Fish allergy is due to our body’s abnormal response to fish proteins such as Parvalbumin which is the major fish allergen which is resistant to heating or cooking and even to acid digestion. This is why some allergic individuals still experience symptoms despite thorough cooking of fish. Fish allergy symptoms are immediate and often severe such as:

• Oral allergy syndrome: Itchiness, Redness or Swelling of the lips, mouth or throat
• Skin: Rashes, Redness, Swelling
• Digestive System: Abdominal pain, Diarrhea, Sudden Vomiting
• Respiratory: Sneezing, Runny Nose, Eye tearing, Asthma
• Anaphylactic Shock: Difficulty breathing, Sudden drop in blood pressure, Weak pulse, Rashes, Nausea and Vomiting (Note: This is a life-threatening allergic reaction)

Diagnosis of a true fish allergy with a physician is important due to its potential life-threatening allergic reactions and to avoid unnecessary food restrictions that lead to lesser food choices and increased cost for alternative food items. There are also other conditions which may mimic fish allergy such as:

• Anisakis Infestation from undercooked fish- Symptoms are due to the body’s reaction against the Anisakis parasite that contaminated the fish. They are commonly found in undercooked fish.
• Histamine Poisoning or Scombroid Poisoning from improperly preserved fish - Symptoms look like an allergic reaction, but it is due to the high histamine content of fishes that are improperly preserved. Bacteria that contaminates the fish produces histamine which may trigger allergic-like reactions.

Prevention of Fish Allergy or Adverse Food Reactions Towards Fish

• Introduce properly cooked fish to infants by 6 - 9 months

A 2010 study has found that late introduction of fish beyond 8 months old is associated with a higher risk of developing fish allergy from inhaling fish particles or vapor while cooking. Thus, the recommended timing of introducing cooked fish to infants is around 6 - 9 months old. The fish must be flaked and free of fish bones to prevent choking.

• Cook fish thoroughly and avoid eating raw or undercooked fish.

Raw fish products such as Kilawin and undercooked fish may contain live parasites such as Anisakis which may trigger severe allergic-like reactions. Thus, cook fish thoroughly to kill parasites and other bacteria which may cause food poisoning.

• Choose fish products that are preserved properly.

Check for the quality of local canned fish and other preserved fish in terms of their food safety handling and if they have signs of contamination such as white, green or black molds, unusual bubbles or smell. Bacterial contamination may increase its histamine content which may cause histamine poisoning leading to allergic-like symptoms.

Nutrition Tips for Those with True Fish Allergy

• Avoid all types of fish and fish products unless you have tolerance to some fishes.

Some individuals can develop tolerance to other fishes based on their specific fish allergy type. Canned tuna has lower parvalbumin content due to its extensive food processing. This can be tolerated by some individuals with fish allergy.

• Be careful with exposure to fish vapor while cooking

Some individuals are sensitive to fish vapors or inhaling fish substances and may experience respiratory allergic reactions such as asthma.

• Try other sources of protein such as beans, legumes, poultry and meat and use iodized salt in cooking and seasoning

Fish is a good source of protein and restricting it from the diet may lead to protein and iodine deficiency. Trying other protein sources and using iodized salt in your dishes may help address this concern.

References:

Virginie, D. (2020). What we know about fish allergy by the end of the decade?. J Investig Allergol Clin Immunol, 30(1).

Connett, G. J., Gerez, I., Cabrera-Morales, E. A., Yuenyongviwat, A., Ngamphaiboon, J., Chatchatee, P., ... & Lee, B. W. (2012). A population-based study of fish allergy in the Philippines, Singapore and Thailand. International archives of allergy and immunology, 159(4), 384-390.

Nwaru, B. I., Erkkola, M., Ahonen, S., Kaila, M., Haapala, A. M., Kronberg-Kippilä, C., ... & Virtanen, S. M. (2010). Age at the introduction of solid foods during the first year and allergic sensitization at age 5 years. Pediatrics, 125(1), 50-59.

Recto, M. S. T., Genuino, M. L. G., Castor, M. A. R., Casis-Hao, R. J., Tamondong-Lachica, D. R., Sales, M. I. V., ... & Dionisio-Capulong, R. C. (2017). Dietary primary prevention of allergic diseases in children: the Philippine guidelines. Asia Pacific Allergy, 7(2), 102-114.