Radiation exposure in small doses good for you?
Small quantities of radioactive materials occur naturally in the air we breathe, the water we drink, the food we eat, and in our own bodies. People receive some background radiation exposure each day from the sun, from radioactive elements in soil and rocks, from household appliances (such as television sets and microwave ovens), and from medical and dental x-rays. Even the human body itself emits radiation. These levels of natural and background radiation are normal.
Measurement is usually quantified in units of rem or sieverts with one sievert equal to 100 rem. There are a number of streaming servers with cameras positioned in front of geiger counters showing the current radiation levels in different regions around the world. Streams in Tokyo and prefectures north of the city are quite popular right now due to the catastrophic earthquake, tsunami, and radiation disaster cleanup efforts.
The biggest scare of radiation is the potential for increased risk of developing one of the many forms of cancer. But we’re all exposed to limited amounts every day. Electronics, microwave ovens, AM/FM radio, incandescent light bulbs, A/C power lines, even rocks expose us to radiation all the time. While these sources falling within the non-ionizing electromagnetic spectrum don’t have the energy to strip electrons in our cells with their low energy long wavelengths, high energy ultraviolet and the even higher x-rays and gamma-rays energies with wavelengths of a million-millionth of a meter can break down chemical bonds and damage our DNA. Simply put, exposure to this kind of energy will kill you dead.
For more info on ionizing and nonionizing electromagnetic radiation check the epa:
So what about limited doses of radiation exposure? There have been all kinds of tests to prove low doses of a substance can have the inverse affects of higher dosages. The name for this phenomenon is hormesis. This term describes generally-favorable biological responses to low exposures to toxins and other stressors. A pollutant or toxin showing hormesis has the opposite effect between small and large doses.
This might explain that while nicotine is a stimulant, smokers feel a calming sensation from smoking a cigarette. Other examples include tests of small amounts of methylmercury improving the hatching rate of mallard eggs and laboratory tests performed on mice using low and high doses of a form of morphine in combination with avoidance learning. Small doses of a dopamine was shown to enhance the ability to learn to avoid electric shocks faster than larger doses which impaired their ability to avoid shock as you would expect.
Single trial passive avoidance learning in mice:
So how about radiation hormesis as compared to mitochondrial hormesis. The general consensus sold to the public is antioxidants are good for you. Foods fortified with antioxidants are supposed to promote good health and stave off disease right? Research, however, suggests that the reverse is true! Antioxidants may actually increase risk of disease.
Hormesis on wikipedia: