It is often the case that something is good for you in small amounts, but bad in large amounts. As expressed by Paracelsus, an early 16th century doctor, “There is no difference between a poison and a cure: everything depends on dose.”

Phillipus Aureolus Theophrastus Bombastus von Hoenheim (Dr. Paracelsus).

Some obvious examples involve foods: an apple a day may keep the doctor away. Fifteen will cause deep physical problems. Alcohol, something bad in high doses, and once banned in the US, tends to promote longevity and health when consumed in moderation, 1/2-2 glasses per day. This is called “hormesis”, where the dose vs benefit curve looks like an upside down U. While it may not apply to all foods, poisons, and insults, a view called “mitridatism,” it has been shown to apply to exercise, chocolate, coffee and (most recently) sunlight.

Up until recently, the advice was to avoid direct sun because of the risk of cancer. More recent studies show that the benefits of small amounts of sunlight outweigh the risks. Health is improved by lowering blood pressure and exciting the immune system, perhaps through release of nitric oxide. At low doses, these benefits far outweigh the small chance of skin cancer. Here’s a New York Times article reviewing the health benefits of 2-6 cups of coffee per day.

A hotly debated issue is whether radiation too has a hormetic dose range. In a previous post, I noted that thyroid cancer rates down-wind of the Chernobyl disaster are lower than in the US as a whole. I thought this was a curious statistical fluke, but apparently it is not. According to a review by The Harvard Medical School, apparent health improvements have been seen among the cleanup workers at Chernobyl, and among those exposed to low levels of radiation from the atomic bombs dropped on Hiroshima and Nagasaki. The health   improvements relative to the general population could be a fluke, but after a while several flukes become a pattern.

Among the comments on my post, came this link to this scholarly summary article of several studies showing that long-term exposure to nuclear radiation below 1 Sv appears to be beneficial. One study involved an incident where a highly radioactive, Co-60 source was accidentally melted into a batch of steel that was subsequently used in the construction of apartments in Taiwan. The mistake was not discovered for over a decade, and by then the tenants had received between 0.4 and 6 Sv (far more than US law would allow). On average, they were healthier than the norm and had significantly lower cancer death rates. Supporting this is the finding, in the US, that lung cancer death rates are 35% lower in the states with the highest average radon radiation levels (Colorado, North Dakota, and Iowa) than in those with the lowest levels (Delaware, Louisiana, and California). Note: SHORT-TERM exposure to 1 Sv is NOT good for you; it will give radiation sickness, and short-term exposure to 4.5 Sv is the 50% death level

Most people in the irradiated Taiwan apartments got .2 Sv/year or less, but the same health benefit has also been shown for people living on radioactive sites in China and India where the levels were as high as .6 Sv/year (normal US background radiation is .0024 Sv/year). Similarly, virtually all animal and plant studies show that radiation appears to improve life expectancy and fecundity (fruit production, number of offspring) at dose rates as high as 1 Sv/month.

I’m not recommending 1 Sv/month for healthy people, it’s a cancer treatment dose, and will make healthy people feel sick. A possible reason it works for plants and some animals is that the radiation may kill proto- cancer, harmful bacteria, and viruses — organisms that lack the repair mechanisms of larger, more sophisticated organisms. Alternately, it could kill non-productive, benign growths allowing the more-healthy growths to do their thing. This explanation is similar to that for the benefits farmers produce by pinching off unwanted leaves and pruning unwanted branches.

It is not conclusive radiation improved human health in any of these studies. It is possible that exposed people happened to choose healthier life-styles than non-exposed people, choosing to smoke less, do more exercise, or eat fewer cheeseburgers (that, more-or-less, was my original explanation). Or it may be purely psychological: people who think they have only a few years to live, live healthier. Then again, it’s possible that radiation is healthy in small doses and maybe cheeseburgers and cigarettes are too?! Here’s a scene from “Sleeper” a 1973, science fiction, comedy movie where Woody Allan, asleep for 200 years, finds that deep fat, chocolate, and cigarettes are the best things for your health. You may not want a cigarette or a radium necklace quite yet, but based on these studies, I’m inclined to reconsider the risk/ benefit balance in favor of nuclear power.

Note: my company, REB Research makes (among other things), hydrogen getters (used to reduce the risks of radioactive waste transportation) and hydrogen separation filters (useful for cleanup of tritium from radioactive water, for fusion reactors, and to reduce the likelihood of explosions in nuclear facilities.

by Dr. Robert E. Buxbaum June 9, 2013