Hormesis - A little radiation may be a good thing

Last Thursday, my wife and I gave a presentation to the new students in the Honors College at WSU on the common reading book, Physics for Future Presidents. One large chunk of the book discusses nuclear power and its risks. When extrapolating to low dose, the author is careful to always state "assuming the linear hypothesis."

This got me thinking about an article in Scientific American that I read back in 2003 on the topic of Hormesis. The idea is that toxins might actually be beneficial when taken in low doses. As an example of Hormesis, exercise wreaks all sorts of havoc on the cellular level, but is healthy in moderation. The explanation is that the body's response in repairing the damage does some good that goes beyond the status quo. At higher levels of exposure, the body cannot keep up with the damage, and toxic effects become - well, toxic.

The red curve in the figure shows the linear hypothesis; the toxicity of a toxin, quantified in terms of the death rate, increases with dose. Hormesis, shown in green, yields a benefit at low exposure levels. Serious scientific studies are finding a hormesis response in many toxicological studies.

Hormesis may describe the effect of ionizing radiation on living creatures such as humans (see the references below). Karl Grossman furiously protests on the anti-Nuke website NuclearFREEPlanet.org. He sees these studies as an obvious ploy by nuclear scientists to pollute the planet, "These scientists don't just want to minimize or even flatly deny the deadly impacts of radioactivity - they want people to think it's healthy." What if it is actually healthy?

Our presentation to the students of the Honors college focused on the notion that decisions that are made based on the facts have better outcomes when not clouded by ideology. We should not bash science just because its conclusions weaken those arguments that support our beliefs.

My point in using this example is not to be an advocate for nuclear energy, nor is it to support the hormesis hypothesis. Rather, it is to illustrate the pitfalls of clinging to an ideology. If the best evidence shows that low levels of radiation is safe and potentially beneficial, then why not loosen standards to reflect the best science?

Some readers may find these arguments reminiscent of the homeopathy hypothesis, that ingesting toxins at levels of zero concentration can cure various ailments. There is absolutely no evidence for homeopathic effects. Wikipedia devotes a page to Jacques Benveniste, who purported to observe such effects (published in the prestigious journal Nature), but whose work has been discredited many times since (blue dot in the figure). A site visit by a team assembled by the editors of Nature at the time of the report in 1988 found serious procedural problems that explained the spurious result.

Sadly, homeopathic remedies are found on the shelves of my local pharmacy and are even covered by the health plans of many countries. I would venture a guess that there is a large overlap between people who use homeopathic remedies and those who deny hormesis based on their anti-nuke sentiments. If so, they may be wrong on two counts.

At the risk of accusations of being pro nuclear, I will post some interesting statistics on radiation, and a comparison of the dangers of various energy sources including nuclear power. Until then, I encourage you to read the informative links in this post. For someone with a more serious interest, I recommend the articles in the reference list, which appear in hard-core scientific journals. If you are left with a desire to dig deeper, there are several hundred more articles on the topic. But, stay away from ideological websites, unless your aim is to feed your ideology rather than learning the truth.

Buon Pomeriggio!

References

Title: Hormesis: The dose-response revolution
Author(s): Calabrese EJ; Baldwin LA
Source: ANNUAL REVIEW OF PHARMACOLOGY AND TOXICOLOGY Volume: 43 Pages: 175-197 DOI: 10.1146/annurev.pharmtox.43.100901.140223 Published: 2003

Title: The frequency of U-shaped dose responses in the toxicological literature
Author(s): Calabrese EJ; Baldwin LA
Source: TOXICOLOGICAL SCIENCES Volume: 62 Issue: 2 Pages: 330-338 DOI: 10.1093/toxsci/62.2.330 Published: AUG 2001

Title: Hormesis: A highly generalizable and reproducible phenomenon with important implications for risk assessment
Author(s): Calabrese EJ; Baldwin LA; Holland CD
Source: RISK ANALYSIS Volume: 19 Issue: 2 Pages: 261-281 DOI: 10.1111/j.1539-6924.1999.tb00404.x Published: APR 1999

Title: Evidence for beneficial low level radiation effects and radiation hormesis
Author(s): Feinendegen LE
Source: BRITISH JOURNAL OF RADIOLOGY Volume: 78 Issue: 925 Pages: 3-7 DOI: 10.1259/bjr/63353075 Published: JAN 2005

Title: Multiple stressors in Caenorhabditis elegans induce stress hormesis and extended longevity
Author(s): Cypser JR; Johnson TE
Source: JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES Volume: 57 Issue: 3 Pages: B109-B114 Published: MAR 200

Title: RADIATION HORMESIS - ITS EXPRESSION IN THE IMMUNE-SYSTEM
Author(s): SHU ZL; LIU WH; SUN JB
Source: HEALTH PHYSICS Volume: 52 Issue: 5 Pages: 579-583 Published: MAY 1987

Title: Exercise and hormesis: oxidative stress-related adaptation for successful aging
Author(s): Radak Z; Chung HY; Goto S
Source: BIOGERONTOLOGY Volume: 6 Issue: 1 Pages: 71-75 DOI: 10.1007/s10522-004-7386-7 Published: JAN 2005

Title: Effect of a continuous gamma irradiation at a very low dose on the life span of mice
Author(s): Caratero A; Courtade M; Bonnet L; et al.
Source: GERONTOLOGY Volume: 44 Issue: 5 Pages: 272-276 DOI: 10.1159/000022024 Published: SEP-OCT 1998

The scientific method and discourse

Since the announcement of a possible merger between the college of sciences (COS) and the college of liberal arts (CLA), many faculty members at our university on both sides of the divide could be heard complaining. In a mixed-party conversation, a CLA colleague vocalized concern that in a merged college, liberal arts would be strong-armed by the sciences, philistines who might not be aware of other ways of knowing.

I was curious about this seeming paradox of alternatives to the scientific method, so I asked to be enlightened. "Discourse" was offered as an example of another way of knowing. This got me thinking about scenarios where this approach might be appropriate. Perhaps an autobiography that describes the suffering of a minority could strike a cord with others who experience the same pain. Similarly, such a narrative could convey the meaning of oppression to outsiders. While the scientific method might be appropriate for studying the brain chemistry underlying emotions, it is not applicable in the human activity of communicating emotions. There is no hypothesis that is being testing, so I am fine with this concept.

Immediately after vocalizing my thoughts, my moment of clarity was yanked away by the accusation that the scientific method is clearly not always appropriate in science. Data can be misinterpreted, protocols changed after the fact, and falsity propagated by stubborn scientists who are too arrogant to change their minds. No scientist would ever claim infallibility. I felt that the accusations were extreme and did not ring true.

I was then lectured on how eastern holistic medicine such as acupuncture, long ignored or belittled by science, was now becoming accepted by western medicine, as was therapeutic touch. I was flabbergasted by this misinformation. It just ain't so! Since I could see the fruitlessness in an appeal to reason, I remained silent and changed the subject.

Sadly, health insurance companies are being strong-armed by patients who are demanding that alternative medicine be covered. When an insurance company caves, it implicitly implies that there is validity to alternative approaches when in fact, these treatments have been shown by double blind experiments to be ineffective. In the end, we all suffer as precious resources are squandered on worthless treatments.

Then there are politicians such as Senator Tom Harkin of Iowa, who have a special interest in alternative medicine and who have used their power to create a government-funded clearinghouse for Complementary and Alternative Medicine (CAM) research. As a result, The National Center for Complementary and Alternative Medicine was established, and now garners a yearly budget of $130 million. While there is a need for studies of alternative approaches that are not potentially lucrative enough for pharmaceuticals to foot the bill, the research is heavily biased by true believers who control the funding, rehashing treatments that have be shown over and over again to be ineffective.

The downside of this "research" is that it bestows the air of legitimacy. As a result, there is growing support for alternative medicine.

If this is what our comrades in CLA generally mean by other ways of knowing, then it does not belong in academics. While all new ideas deserve to be heard, ones that have been shown to be false and counterproductive need to be put to rest as a historical curiosity - a lesson in how the mind can be fooled and how we can avoid making similar errors in the future. We need to learn the difference between a closed mind and letting go of notions that are known to be false unless reliable new evidence is brought to light.

While I have been generally in support of government involvement in healthcare to insure universal coverage for all, the fact that centralization gives politicians the power to decide what is science gives me cause to reconsider my position. One may protest that government is not so capricious; but, consider that the French healthcare system covers homeopathy, an idea that is utter nonsense both in its inefficacy as established in scientific studies, as well as in the fact that its basis runs contrary to all that we know. Sadly, even private insurers are covering alternative medicine; so, both government and the private sector have failed us in optimizing health outcomes.

Once again, I am too exhausted to fight a war that long ago has been won on the battlefield of reason. For further reading, I recommend the report prepared by the Center for Inquiry, which describes the history and science of acupuncture; and Robert Park's excellent piece on alternative medicine.