A nationwide survey has found that nearly 7 million people in the U.S. – about 2.3 percent of the population – are allergic to seafood. Shellfish allergies are the most common at about 1 in 50, while fish allergies affect about 1 in 250.
The survey was conducted nationally and included about 3,000 participants. Most allergic reactions to fish are to raw fish (sushi) rather than cooked, and most people who are allergic to one type of fish are likely to be allergic to another as well, but cross-allergies from shellfish to fish (or fish to shellfish) are unlikely. Allergies to crustaceans are most common.
The reasoning for cooked fish being less allergenic, allergists believe, is because the common proteins that cause allergies are often broken down under intense heat. This explains why canned fish often does not produce an allergic reaction.
The survey shows that seafood allergies are on the rise but not significantly when compared to other food allergies. Findings in other surveys in recent years were similar. The study is due to be published later this year.