Fish allergy, a global immunoglobulin E (IgE)-mediated condition with no cure, persists for life in nearly 90% of patients and is usually managed by avoiding it. Some fish-allergic individuals tolerate canned fish; however, the reasons remain unclear. Canning might reduce allergenicity by altering protein structures, but comprehensive studies of canned fish allergens are lacking. Allergic reactions to canned fish highlight allergenic potential, underscored by heat-resistant allergens such as parvalbumin (PAV), tropomyosin (TROM), and collagens that remain intact despite cooking. Further research is crucial to ensure the safety of consuming canned fish for people with fish allergies.
In a recent study, researchers evaluated the safety of canned fish consumption for fish allergic patients by analyzing serum immunoreactivity of fish allergic subjects and assessing the content and integrity of PAV in fish products. in box. In the present study, pediatric patients aged one to 18 years with clinically confirmed fish allergies were recruited from Westmead Children’s Hospital, Australia, and their sensitization was assessed using diagnostic tests such as skin prick testing and detection of specific IgE. If these patients or their parents showed interest in incorporating canned fish into their diets and a history of canned fish tolerance was unclear, they underwent oral food trials with canned fish such as tuna or salmon.
Serum from patients without seafood allergies was used as a control, and the research was conducted ethically, with all guardians providing informed consent while maintaining patient confidentiality. The study focused on understanding the protein profiles of various canned seafood products, specifically examining the allergenic properties of these proteins. In the analysis of canned fish products, a significant variation was observed between the protein profile of canned fish and that of crude extracts (CRE) of the same fish. Specifically, proteins in canned products appeared more aggregated or degraded, resulting in a lack of distinctive bands on the protein profiles. The study found no significant differences in the protein profiles of canned salmon from different species or producers.
However, distinctions have been noted between canned skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacores), containing smaller proteins and larger proteins. Furthermore, the PAV allergen was not detected in any canned fish products, although it was present in salmon and sardine CREs. Additionally, some proteins in canned fish products have been found to bind to specific immunoglobulin E (sIgE). The extent of sIgE binding varied between types of fish; for example, yellowfin tuna showed more sIgE binding than skipjack tuna. Furthermore, while salmon and sardine CEs demonstrated strong sIgE binding to proteins between 11 and 14 kDa, tuna CEs lacked this pattern. Mass spectrometry techniques identified major fish allergens, including PAV and TROM, as sIgE-binding proteins.
An in-depth analysis revealed that these proteins were present in varying quantities in different canned fish products. For example, canned pink salmon contained significant percentages of PV and TM, while canned sardine contained abundant amounts. The data collected showed that 66% of the 53 fish allergic patients had sIgE binding to canned fish proteins, with canned sardine recording the highest percentage of sIgE binding, followed by salmon and tuna in box. The specific proteins that the patient sera bound to varied, but a significant portion was bound to smaller proteins in the canned salmon.
Sardine showed frequent sIgE binding, especially in certain protein weight ranges, and this trend was also observed in salmon and tuna. Finally, an analysis of the amino acid sequences of fish allergens revealed that TROMs were more conserved in fish species than PAV. While sardine and salmon tropomyosins were found to be 84–90% similar, parvalbumin isoforms showed less similarity, many of which were only up to 80% similar. The presence of myosin heavy chains was also detected, which is not yet a universally confirmed fish allergen. However, the safety of consuming canned fish specifically for allergy sufferers requires individualized assessment.
- A cura del Dr. Gianfrancesco Cormaci, PhD, specialista in Biochimica Clinica.
Pubblicazioni scientifiche
Taki AC, Ruethers T et al. Allergy 2023 Aug 31: 15864.
Molecules. 2022 Sep; 27(17):5674.
Minerva Pediatr. 2020; 72(5):408-415.