TOKYO -- As nut allergies are becoming more common in Japan, the Mainichi Shimbun looked into which varieties are most likely to cause reactions, and what sort can occur.

Question: What ingredients must be labeled in Japan to prevent food allergies?

Answer: Based on the Food Labeling Act and taking account of factors such as the number and severity of cases, certain designated ingredients need to be labeled on processed foods and other products. There are currently eight such ingredients, including eggs, wheat, shrimp and crabs. Twenty more ingredients are quasi-designated with recommended labelling, including red caviar, orange and banana.

Q: Can other ingredients be added to the list?

A: The Consumer Affairs Agency (CAA) plans to add cashews to the list. Labeling of pistachios is also being advised, with both expected to be added within fiscal 2025, beginning in April. Other tree nuts have been recommended for labeling, such as walnuts in 2023 and macadamias in 2024.

Q: Are allergies to tree nuts increasing in the country?

A: In a 2023 CAA study, walnuts were second only to chicken eggs as a cause of food allergies, representing 15.2% of the total. Tree nuts have seen an increase since the prior study three years earlier. The percentage for cashews grew by 1.6 times, taking seventh place with 4.6%. The rise is thought to be due to a growing consumer trend toward maintaining good health. Aside from being eaten raw, tree nuts are also commonly found in products such as dressings, sweets and breads.

Q: What kind of symptoms arise?

A: Allergy symptoms include itching, hives, difficulty breathing and nausea. Severe cases can cause disturbances in consciousness and anaphylaxis. The CAA, maintaining that cashews, pistachios and other tree nuts cause severe symptoms in many cases, is pointing out the need to take measures to prevent accidental ingestion.

(Japanese original by Reiko Ide, Lifestyle, Science & Environment News Department)