There are radioactive substances in almost everything we eat. These are substances which are so long-lived that they originate from the creation of the universe and thus also the beginning of the Earth. They are part of the conditions under which all life has evolved, The elements is taken up from the soil by plants and occurs in food. Bananas and Brazil nuts are the most well known examples of foods that contain radioactivity.
We do not become radioactive by eating them, as our body is already – like the whole world – radioactive completely naturally.
Bananas #
Bananas are slightly radioactive because they are rich in potassium. Like other elements, potassium has various isotopes, several of which are radioactive, including a small amount of Potassium-40.
A typical banana contains half a gram of potassium, of which 0.0117% is potassium-40, which means it emits 31 beta radiations per second.
Eating a banana thus gives an extra dose of radiation of 0.0001 mSv.
A lorry full of bananas is radioactive enough to trigger a false alarm on a radiation detector looking for smuggled nuclear weapons [1].
