Parvalbumin content of fish species varies considerably - possibly contributing to variable allergenicity

95% of fish-allergic patients are sensitized to the major fish allergen parvalbumin. However, clinical reactions to different fish species vary considerably in symptoms, intensity and frequency in allergic subjects.

This study quantified the parvalbumin levels in salmon, trout, cod, carp, mackerel, herring, redfish and tuna.

Parvalbumin contents were (SDS-PAGE scanning):

- less than 0.5 mg per gram tissue for mackerel

- 0.5-2 mg for salmon and trout

- more than 2 mg for cod, carp, redfish and herring

Parvalbumin contents were (ELISA)

- less than 0.05 mg for tuna

- 0.3-0.7 mg for mackerel

- 1-2.5 mg for salmon, trout and cod

- more than 2.5 mg per gram raw muscle for carp, herring and redfish

The parvalbumin content of processed samples (cooked/commercial) was 20-60% lower.

The parvalbumin content of most commonly consumed fish species varies considerably. Differences range from severalfold to 100-fold. This has to be taken into account when designing food challenge tests and advising fish-allergic patients.

Fish-allergic patients should avoid all fish species until a species can be proven safe to eat by provocative challenge (Annals of Allergy and Imm, 1999).

References:

Important Variations in Parvalbumin Content in Common Fish Species: A Factor Possibly Contributing to Variable Allergenicity. Kuehn A, Scheuermann T, Hilger C, Hentges F. Int Arch Allergy Immunol. 2010 Jun 17;153(4):359-366.
Epitope Mapping of Atlantic Salmon Major Allergen by Peptide Microarray Immunoassay http://goo.gl/OGCnn
Image source: Gadus morhua, Atlantic cod. Wikipedia, public domain.