Hormesis, Again

[Richard Hull]

I just read a paper by T.D. Luckey in RSO MAgazine. (volume 8, #4)

He is a prof emeritus at Univ of Missouri and has researched Gnotobiology for 8 years and taught biochemistry for 30 years. He lectures widely on nutrition, intestinal microbiology and radiation hormesis.

His 20 page paper is interesting, if not down right counterbary!

Some quotes I found interesting.......

"We live in a subclinical deficiency of ionizing radiation."

" A threshold exists between biopositive and bionegative effects. This threshold is called - Zero Equivalent Point or (ZEP)."

"ZEP negates the LNT (linear no threshold) concept."

In discussing national and international agencies that cling to LNT and ALARA he notes...

"These agencies consider the perception of harm to be more important than ovewhelming scientific evidence showing that stimulation with low doses is a general rule in biology."

And........

The thesis is clear. There is no risk and considerable benefit from chronic whole body exposures to low doses of ionizing radiation. The evidence shows national and international agencies promulgate harm when they severely restrict exposures to ionizing radiation. Their goal should be health."

There is much more.

This fellow is obviously well trained and speaks with some authority within this field. He is not the only voice, however, and others will certainly take any and all of his work to task. Still, there is a growing hormetic cadre of researchers that seem to attract a counterpart medico or researcher who decrys this point of view.

I would love to read Luckey's book , a scholarly work with miles of references published by the prestigious scientific, CRC press but like all such works by CRC and Elsvier you will have to pony up $379.00 to the 370 page tome. Too bad I don't have a birthday and wedding annivesary on Christmas day. I might have received it as a gift.

Hormesis has always stimulated discussion here and this paper and others I have read are quite impressive, but who here would want to be in a double blind controlled test on such a vast clinical trial to show who is right. Remember, one group is doomed to more cancers than the other.

Human genetics passed down to each of us is probably more of a factor in who gets cancer, who is very suseptable, who is mildly suseptible, who is cancer neutral and who is virtually cancer proof over a full life. Immune system genetics is a separate issue outside of the cancer. The best that might come of it all is a statement like.

"given a general cross section of 1000 city dwellers, 1000 country dwellers and 1000 high elevation dwellers all in good health, all with no rash history of cancer in their families, blah blah blah......"

Such a study would still, regardless of pro-hormesis or Pro-LNT results, only tell you where to live if you were a lucky guy whose family was mostly cancer free.

Thus, you could bath in 10X whole body background until such time as you got hit by a bus in your 39th year or got shot during a robbery, ending your days with a hormetically boosted immune system in full vigor or have the same ill fate befall you as a totally radiation starved ALARAite with nearly zero cell damage attributable to radiation.

Life is a crap shoot. Medico stuff (they call it science) even with perfect control grouping is about 5 notches to the left of black magic and a cast o' them bones.

I'll take my external rads as they come and avoid the truly hot stuff but not shrink from a good regular dose of chronic low level stuff. I just gotta' remember to make it wholebody. Internal rads, for me, will always remain a no-no. (an inverse square law kinda thing I hold with)

Richard Hull

[UG!]

very interesting. i have been moderatly supprised to learn, on my cause, that one can recieve a properly hefty dose of radiation ~3Gy mabey or as much as 20Gy if spread out over a few months and suffer a relativly moderate encrease in ones liklyhood to get cancer, mabey 5% or so, compaired to a 25% background. Almost unoticeable below the noise. not entirly supprising i suppose considering the storm of heigh energy stuff raining down on us 24/7 (200 muons m^2 s^-1, iirc) and thats just the muons, all those high energy gammas creating positron/electron pairs everywhere and suchlike.

as Richard states though internal stuff (especialy those nasty alphas are rather bad), one must take the Gy to Sv conversion factors for different radiations (alpha being 20), and the weighting factors for various bits of ones anatomy. it becomes a decidedly non-trivial process.

not supprising that government agencies assume a linear model, and attempt to keep peoples does to a minimum though, it seems resonable (to me) that they should err on the side of causion, when dealing with something that is known to be damageing in high doses.

on a side note, all my lecturers have been on the news with all this 210Po media interest

Oliver

[davidtrimmell]

Internal vs External dose is the same as long as you know how much and weigh the type, target organ, etc. correctly. Dose is dose.

ZEP sounds like zero point energy to me

Regards,

David Trimmell

[UG!]

this is true, i didn't make that very clear in the last post. one must also take into account the biolobigal halflife of the radionuclide in question and the form it was ingested in.

Oliver

[JohnCuthbert]

There's someting about this hormesis thing I don't understand. If the presence of a little radiation stimulates the body's immune system to provide better health overall why hasn't millions of years of evolution broken the link and ensured that the immune system is always that good, even if the radiation is missing?

[Verp]

It’s an odd fact of biology that what is bad for an organism in large amounts, be it a toxin, a crop plant competing with a weed, people experiencing stress, etc. the organism usually responds positively at a much-reduced rate. When it is graphed out, there is an upward trend in some measure of vigor that reaches a peak, then turns down as whatever it is becomes a more familiar bad thing for the organism.

I think it has something to do with the organism responding to the weak stimulus by overshooting a bit in the area of vigor, as it gears up metabolically to deal with the issue. That a biological feedback loop with the added complexity to try to keep things more level might be more metabolically energy intensive than simply having a less complex loop that tends to overshoot at the low levels of the stressor, or that having a more complex feedback loop has more things to go wrong with it. Either way, that would be a selective disadvantage.

Rod

[JohnCuthbert]

What's the optimal level for exposure to lead or cyanide?
I can see how for some things like selenium (where some is required but too much is toxic, there is an optimum. I just don't understand why, for example, a plant wouldn't grow "flat out" in the absense of weeds. One that did would outgrow those that don't and so ought to eave more progeny. (In this sense, when I say "grow" I don't just mean get taller I mean generally expend the available resources to get more progeny- that might mean more fruit, bigger flowers, whatever. What I don't understand is why it would "hold back" in the absense of some noxious stimulus.

[Richard Hull]

Backgorund is background and any organism lives to its background. The general observation is that stimulus above background stimulates the organism or system. However this is only to the point where overstuimulation is detremenetal or stresses the organism or system.

There are a million examples, some scientific and some trite.

A student placed in a dumbed down environment is dumbed down for the most part with his dumbed down peers in a reduced performance or lower stimulus environment. All manner of complication in complex systems fouls a clear understanding along lock step scientific lines, but still, general rules seem to apply. There are flyers such as kids in a dumbed down environment that are drawn to self stimlate and seek out, but it is never the norm and a percentage of even these are dragged down by the herd.

The world and civilization worked splendidly with Neandertahls, Cro-Magnons and the like. It worked fine with warlords, devine right of kings and domination of empire. Yes folks were treated like crap and died en-mass just a they do today, but just due to different causes. The world organism lived to its stimulus level.
As more stimulus was applied more smoothly civilization, by our view, improved. Slowly.

Overstimulation, world wide campaigns fo conquest stressed the organism. Thousands fo cells (people) within the organism died, but other things happened, the expansion of ideas swept over both the conquered and the conquerers, by fits and starts, the organism advanced and grew for good or ill, but it carried on. It mutated

Individual cells within a society animal or an individual animal within that society live, get stimulated, advance, retard and die. Nonetheless, the overall organism survives as it lives to its stimulus level. It either adapts or dies.

Hormesis on the level of the living society is ultimately good inspite of a lot of cells getting solughed off. Hormesis, at the level of the human body, is just another complex system that has adapted to its own background. No stimulus, no advance, possible decay through failure to mutate or auto-stimulate. Who knows? Such entities are called "complex" for a reason.

Biological and sociological systems are tied together and respond in very similar fashion, but in complex ways that are only generally predictable via statistics rather than along specific predictable, repeatable scientific paths.

Hormesis is just another of these apparent paths of possible stimulus and reponse curves. The issue is that it involves future health of an entity that can bring suit and, as such, is a real hot potato issue that a simple LNT guy can dismiss because he feels safe and is covering his or her ass nicely by just saying no to all radiation.

No one has yet been sued for denying anyone else their God-given right to an extra helping of chronic wholebody radiation. The way this fickle world is acting and reacting, someone will certainly be the first to do so in future.

For right now though, the ALARA people are safe as houses. It is always better and safer to sit and do nothing or advocate zero case dosing in medicine, for lawyers are always circling above. If someone dies due to dosing, it is the medicos fault; If they die through inaction or zero dosing, it is the will of god.

Richard Hull

[JohnCuthbert]

Human civilisation does not evolve in the same way as biology. We can chose what to teach our children, but we can't (up till very recently at least), choose what genes they get. The evolution of complex society under a given level of stress is an interesting study in its own right but I'm not sure it's a good model here. Is there ay clear evidence of a biological/ biochemical mechanism for hormesis? If there is, for example that radiation stimulates DNA repair mechanisms, then I still wonder why evolution hasn't got the "set point" right and that we need some additional damage to get the best life expectancy.

[Richard Hull]

We really have no idea what the past radiation levels for earth is or was. We can be sure however it has varied probably over at least an order of magnitude or two depending on the various calamities induced by geologic and extraterrestrial influences. Right now we are looking at .3 rads/year for ALARAists.

3.0 rads or 30.0 rads a year would not kill man or civilization. it would be mere childs play to our species. It might kill a bunch of non-preped ALARAists and mutate us a bit, but if present long enough, we biologics would adapt. The great thing about mutation is that if left alone the best mutant wins. None of us want to mutate, mostly out of fear and not out of the calm wisdom that it is nature's way.

Go back a billion years and there was a lot more earth based NORM around due to the original U load on the planet and also a lot more Radon daughters, etc. However, if the atmosphere was thicker and cloud laden back then, then the space particle load may have been lower.

Anyone know a radio-archeologist?

Richard Hull

[Frank Sanns]

Radiation hitting the ground varies with the Earth's magnetic field strength. At times of low magnetic field or during null at a reversal, the radiation levels increase but only I think by a factor of less than 10. Not really a significant dose. One can only assume that the Sun's output over the last million years or more has been just like it has been over the last historical solar cycles so not much has changed. The gamma ray bursts from outer space like the one a decade or so ago that gave everybody on the other side of the planet the equivalent of a chest x-ray was not long term so it does not play into the long term hormesis theory.

Frank S.