Brazil nuts are roughly 1,000 times more radioactive than most other foods.

Brazil nuts (Bertholletia excelsa) are unique because their extensive root systems reach deep into the soil to absorb Radium-226 and Radium-228. These are naturally occurring radioactive isotopes found in the earth's crust. While most plants do not accumulate these elements, the Brazil nut tree concentrates them in its fruit at levels up to 1,000 times higher than other common foods.According to the Health Physics Society, the radioactivity of Brazil nuts can range from 40 to 260 millibecquerels per gram. For comparison, most fruits and vegetables contain less than 0.1 millibecquerels per gram. This phenomenon is primarily due to the specific soil chemistry in the Amazon basin where these trees thrive. The soil is often rich in naturally occurring radioactive materials that the tree’s roots efficiently transport to the canopy.Despite these numbers, the radiation dose from eating a few nuts is negligible compared to everyday background radiation. A person would need to consume an enormous quantity of nuts daily to reach any dangerous threshold of radiation exposure. Most of the ingested radium is not even absorbed by the body and is instead passed through the digestive system within a few days.Beyond radioactivity, Brazil nuts are also known for their high selenium content. While selenium is an essential mineral for thyroid health, excessive consumption can lead to selenosis. Therefore, health experts generally recommend limiting intake to one or two nuts per day for reasons unrelated to radiation. This ensures you get the nutritional benefits without any risk of toxicity.