There are radiation horror stories centering on Hiroshima, Chernobyl, and Fukushima. However, there are also mundane matters like radioactive potassium occurring naturally in bananas and potatoes, among other edibles. There’s no way to avoid all radiation since we are exposed to it from our bodies – a disconcerting thought since doctors know ionizing radiation can damage and mutate DNA, which sometimes leads to cancer.

But like so much else, dose is the key. There is exposure in the form of dental and other X-ray exams that contribute to one’s overall better health. The same is true with a full-body CT scan. The Health Physics Society has established safety levels for radiation but cautions these amounts are just educated guesses. From the Society: “There is considerable uncertainty associated with the estimation of risk from relatively low doses.”

Depending on the amount, length, and frequency of exposure, there may be a risk from certain types of radiation, or maybe there isn’t. Dr. Harriet Hall wrote that in some cases, the risk is so low that tens of millions of people would have to be studied “to overcome the signal-to-noise ratio in the data, and the risk is confounded by varying background levels of radiation and other factors.” In short, there’s no practical way to study this issue completely.

While we can’t know for sure the danger levels for all types, there is no reason to assert that low-level radiation is beneficial, an idea championed by some and based on the notion of hormesis. According to the National Center for Biotechnology Information website, “Hormesis is a term used by toxicologists to refer to a biphasic dose response to an environmental agent characterized by a low dose stimulation or beneficial effect and a high dose inhibitory or toxic effect.” In other words, a little can be good, too much can be bad or even fatal. For example, two Advil will help you recover while you lie on your back, while two bottles of Advil will put you on your back permanently.

Some proponents claim that low doses of radiation can kickstart DNA repair and make the recipient healthier. One such believer, T.D. Luckey writes, “Hormesis is the stimulation of any system by low doses of any agent. Large and small doses of most agents elicit opposite responses. A wealth of data presents irrefutable evidence of the benefits that radiation provides for a great variety of organisms: Decreased infections, decreased cancer death rates, increased fecundity and average lifespan in humans.” Luckey attributes these abilities to biological stimulation and suppression of genes, enzymes and other proteins that indicate an activated immune system. He insists there is evidence that ionizing radiation is essential for life.

However, in an article for Human and Experimental Toxicology, Kirk Kitchin and Wanzer Drane criticize the use of hormesis to assess risk/benefit ratios. For starters, they point out that hormetic dose response curves are mostly unknown. (The dose-response relationship refers to the risk of a defined outcome produced by the amount given and the level of exposure).

Second, the duo caution there is the chance of a random occurrence of hormesis, bedsides there being a little data on hormesis’ repeatability. There is also the possibility of post hoc reasoning, and the chance that hormesis represent the total of many different mechanisms and multiple dose-response curves – some beneficial, some negligible, and some toxic. In short, we are unsure if intentional exposure to low doses of radiation may carry benefit, but there is insufficient reason to assert this, and there could be a great danger in being wrong.