Radiation Hormesis

Hormesis is a medical term that notes that many substances show positive effects to health at low dosages, but are dangerous at high dosages. Most drugs fall into this category. . Hormesis was discovered by Hugo Schulz, a professor of pharmacology at the University of Greifsalf in the mid 1880's. He discovered that formic acid (which would kill yeast at high doses) was helpful in their growth at very low dosages. This discovery was so surprising, that he and his assistants checked, and rechecked their results for a couple of years before publishing.

For example, the drug aspirin (salicylate acid), is helpful at low doses, but at high doses is lethal. (In 2004, there were 20,000 cases of moderate aspirin poisoning, and 43 deaths.)

There is overwhelming evidence that very low levels of radiation are helpful to human health.

Discussion

Studying the effects of massive doses of radiation in a very low time period (from survivors of the atomic bombs at Hiroshima, and Nagasaki) it was found that the chance of cancer increased linearly. The larger the dose, the greater the chance of cancer.

However, damage to cells occurs all the time, and they are constantly repairing themselves. Logically, radiation damage to cells, that is below the rate at which cells repair themselves would have little effect. There were three basic ideas on how to model radiation damage: 'Linear No Threshold', the 'Threshold Model', and 'Hormesis'.

A threshold model was the most logical, but very early radiation safety standards assumed the wildly conservative Linear No Threshold model, assuming that the safety standards would be relaxed as more research came in.

Linear No Threshold (LNT) says that there is NO level of radiation which is safe. Given that we are bathed in radiation all the time, from cosmic rays, ground radiation, and radiation from inside our bodies, the LNT is very suspect. Surely if our radiation dose was equal to, or lower than, the normal background radiation, there would be no harm to our health?

Most scientists assumed that the Threshold Model would be correct. Below some dose the radiation damage was trivial or non-existent, above the threshold dose, it would do harm.

However, as time passed, the evidence accumulated that at very low levels of radiation, there were positive health effects, and some low amount of radiation was helpful to human life.

Sadly, the regulatory regime in most countries, did not update radiation safety standards in light of this new evidence.

Samples of Research

Science Direct's study on radiation hormesis (volume 902, Dec 2023).

ResearchGate - A message to Fukushima: Nothing to Fear But Fear Itself.

Speculation of Why Radiation is Helpful

Life evolved (and is still evolving) in an environment filled with background radiation. (In Earth's early history, this background radiation dose was higher.) It is not surprising that some metabolic pathways would come to depend on a certain amount of radiation in the environment. That said, most speculation as to why low doses of radiation is helpful falls into two categories: 'Exercising the Immune System' and 'Stimulating Repair Mechanisms'.

Stimulating Repair Mechanisms

Stem cell therapy found that the stem cells injected into humans aged rapidly, but if irradiated, they lived longer. The radiation triggered improvements in proliferation, mobility, and chondorgenic differentiation capacity, (which improved cell longevity). This is thought to have been caused by stimulating repair mechanisms in these cells.

Radiation Regulation and Mars Exploration

In most countries, radiation safety standards are based on the Linear No Threshold model, which has been shown to be wildly incorrect.

In the city of Ramsar Iran, natural radiation is 50 times that of most areas on Earth, and they show no higher levels of cancer or other forms of radiation disease. Nor are the average lifespans lower than similar cities (with much lower levels of radiation) in other parts of Earth.

If the radiation dosage required for astronauts was at the level of Ramsar, far lighter and less expensive radiation protection would be needed.

This youTube video nicely summarizes the radiation levels of Mars exploration and discusses safety concerns. https://www.youtube.com/watch?v=VluEllUrseE&list=LL&index=11

See also: https://www.youtube.com/watch?v=gzdLdNRaPKc&list=PL994EB042117A7F6D&index=66