Research on internal exposure and assessment from food intake using a whole body counter and self-administered questionnaires

Radioactive nuclides can enter the human body through inhalation or ingestion, with internal exposure from food depending on the radionuclide type and intake. This study aimed to assess dietary radiological effect using whole body counting (WBC) measurements and self-administered food intake questionnaires. A survey was conducted on 105 people between July 31, 2023, and February 6, 2024. Food intake questionnaires analysis estimated the average internal exposure dose from 40 K due to food ingestion at 208.42 μSv/y, and from 137 Cs at 254.24 μSv/y. WBC detected only 40 K, while 137 Cs was undetectable. Internal exposure factors differed significantly by age, height, weight, body mass index, and whole-body index. The highest activity among men was 5012.7 Bq in their 20s, and among women, 2999.5 Bq in their 50s. Internal exposure from ingested food was negligible compared with the average annual natural background radiation dose of 2.4 mSv/y received by the general public. WBC measurements show that 40 K intake through food remains relatively constant, underscoring its role as a physiological marker, while the non-detection of anthropogenic radionuclides suggests minimal radiological risk from the current food supply.