There are several ways to realize the vast implausibility of — and thus the vast amount of information conveyed by — radiation hormesis. If you are not an experimental scientist, you may not realize how incredibly hard it is to find a treatment that substantially improves something complex. Think how hard it would be to make your laptop work a lot better. Not by redesigning and building a different laptop — but by doing something to the carefully-designed laptop you have now. Has such a thing ever happened in the whole history of engineering? Probably not. Or consider the possibility that shooting a bullet at your laptop (or any other complex machine) will make it work a lot better.Â Absurd. Couldn’t possibly happen.
Yet that is exactly what happens in radiation hormesis: Small amounts of radiation improve health. This review article gives a wide range of examples. Experimental:
Bhattarcharjee in 1996 showed that when the mice preirradiated with just adapting doses of 1 cGy/day for 5 days (without a challenge dose), thymic lymphoma was induced in 16% of the animals (Bhattarcharjee 1996). Interestingly, when preirradiated mice were exposed to a 2 Gy challenge dose, thymic lymphoma was induced again in 16% of the animals. However, the challenge dose alone, induced thymic lymphoma in 46% of the mice.
Cancer frequency among [United Kingdom] nuclear power plant workers was lower than the national average (Kendal et al. 1992).
(I’ve never heard anyone complain there wasn’t enough radioactive radon in their basement, but in some cases that’s true.) Thomas Luckey, the discoverer of the effect, wrote a book about it, reflecting the vast number of examples.
What does it mean? Obviously it supports my umami hypothesis. Life evolved in a world of junk and damage; that junk and damage was used to make things work better. Think of a police force. They function best spread over a city, travelling here and there. When there’s a crime, someone will already be close and get there quickly; many crimes will be stopped in progress. A low crime rate is better than a very low crime rate because it gets the police out of the police station and allows them to practice their skills. With too little crime, the police spend most of their time in the police station. When a crime occurs it takes longer to reach the scene (so small problems become big ones) but also, having nothing else to do, they overreact: treat small problems as big ones. That our body’s defense mechanisms are slow to react means infections and cancers become bigger than necessary (and sometimes lethal); that they overreact means we get autoimmune diseases.