Saturday, October 25, 2008

Poisoning science

No, not anything about climate change, but an interesting New Scientist article that I was reminded of by the slightly pointless discussion about bottled water versus tap on this post.
"WHAT doesn't kill you makes you stronger" is a phrase often used to explain the resilience of people who have endured hardships. Like many aphorisms it contains more than a grain of truth. It describes the theory of hormesis - a process whereby organisms exposed to low levels of stress or toxins become more resistant to tougher challenges.

The theory of hormesis has been around for decades, but has long been met with scepticism or downright suspicion. In recent years, however, biologists have pieced together a clear molecular explanation of how it works, and hormesis has finally been accepted as a fundamental principle of biology and biomedicine. The question now is how to take advantage of hormesis to live longer and healthier lives.

The rest of the article is, unfortunately, behind a subscription wall and, during the massive clean-up that my flat so badly needed last week, I must have junked the issue (so, in what Timmy calls a "bleg", if anyone could email me the article, I'd be incredibly grateful).

However, the theory of hormesis has been around for some time, and can generally be described thusly...
Hormesis (from Hellenistic Greek hórmēsis "rapid motion, eagerness," from ancient Greek hormáein "to set in motion, impel, urge on") is the term for generally-favorable biological responses to low exposures to toxins and other stressors. A pollutant or toxin showing hormesis thus has the opposite effect in small doses than in large doses.

The biochemical mechanisms by which hormesis works are not well understood. It is conjectured that a low dose challenge with a toxin may trigger certain repair mechanisms in the body, and these mechanisms, having been initiated, are efficient enough that they not only neutralize the toxin's effect, but even repair other defects not caused by the toxin.

This was, in fact, the mechanism described—and apparently tested—in the NS article: effectively, one slightly damages the cells—put them under stress—and the bodies repair mechanisms kick in and repair not only the affected tissues but also any damage to surrounding areas. So, what you are doing is making the body repair itself before it would naturally do so, before the damage might become dangerous: and in some instances, these repairs can also create a future defence against the poison introduced—after all, the idea building up an immunity to a poison—iocane powder?*—by taking graually increasing doses has dominated many works of fiction!

In fact, one does not even have to introduce a poison, as such. As regular reader will know, your humble Devil tends to eat somewhat erratically, and rarely mor than once every other day. The reason that the article caught my attention was that the researchers had also shown, contrary to what so many people have warned me, that those who ate, say, every other day tended to be healthier than those who ate more regularly, because of hormesis.

An interesting idea, I think, and might be useful for medical purposes. It is certainly relevant to the world around us and to the state (and society)'s mania for ever more stringent toxin eradication. For, if hormesis does work, this may, in fact, be making ourselves more unhealthy than previously—a theory that might also apply to the ever-increasing incidences of allergies...

* A very fine film.


Mark Wadsworth said...

I thought that this hormesis was generally accepted to exist*, and similarly that if you were nuts about disinfecting everything all the time, you'd simply become more susceptible to germs.

* when babies eat mud in the garden, parents just laugh it off and say 'They are building up a resistance to germs'.

Oxbridge Prat said...

Have just emailed you a copy. Enjoy.

barry norman said...

"Whatever doesn't kill you makes you stranger." The Joker - Batman.

Surely this is a more accurate description of the weird times we are living through, and even how hormesis works. Sometimes it may be better to be stranger than stronger.

The Filthy Smoker said...

Interesting. This backs up what most sensible people intuitively believe to be true. Unfortunately, environmental and health policies are increasingly based on the opposite theory - linear regression - in which there is a straight line between exposure and risk that decreases exponentially. At high doses, this makes sense (eg. smoking 2 packs a day is more hazardous than smoking 1 pack a day). But this common sense (and provable) observation is taken to extremes because it assumes there is no safe level of exposure. Very, very low doses of secondhand smoke/dioxins/benzene/diesel fumes/radiation/alcohol during pregnancy/chlorine in water etc. etc. are assumed to carry a risk to life, albeit a lower risk than would be the case at high exposure.

This is bollocks because it assumes that the human organism cannot cope with trace amounts of 'chemicals'. Someone (I can't remember who) said that it is like saying that because 10 people out 20 drown crossing a 10 foot deep river, then 1 person in 20 must drown if they stand in a foot deep puddle.

And as you suggest, DK, it is likely that the absence of exposure to supposed 'toxins' in childhood explains the massive rise in allergies and asthma in Western countries.

The Filthy Smoker said...

I should clarify that there is nothing wrong with linear regression per se; it is linear risk extrapolation that is the problem. Anyone who is *very* interested in its relation to hormesis might want to read this

Ed said...

Co-60 in the rebar of concrete Taiwanese apartments.
Should be the most famous of all.
'course we've built such strong bodies devoted to reducing radioactive exposure to nil that there is no way to actually act on the ideas raised by this serendipitous study.

Mark Wadsworth said...

Re what Ed says, there's more to it than that.

Of course radioactivity is usually harmful, but one of the reasons why there is such a vast diversity of different life-forms, is because planet earth is actually surprisingly radioactive -> mutations, but even if 99% of mutations are harmful then 1% are beneficial -> evolution and so on.

Re what Filthy Smoker says, I am absolutely sure that somebody was once commissioned to do a study in California that was supposed to 'prove' that children of parents who smoked had more lung disease etc but he gave up when he realised that it wasn't true; a very moderate exposure to diluted second hand tobacco smoke actually had - statistically speaking - a beneficial effect.

But I can't find a link right now.

Gareth said...

Eating infrequently makes you healthier - I can buy that. The toxins produced as we process food in our guts must be quite a problem for the body to deal with. Eating infrequently would reduce this shock to a more manageable (and beneficial?) level.

Perhaps eating less frequently also allows the body to expend more energy repairing itself instead of dealing with food.

Here is a New Scientist article on 'feed a cold, starve a fever'. By eating infrequently you might be in starve a fever mode on a regular basis and are better for it.

TheFatBigot said...

If I didn't eat regularly I'd lose a lot of my charm.

Oh, no, sorry, that's chins.

BB said...

Mark Wadsworth.

Although not the study that you referred to, the results of this study reached a similar conclusion in 1998.

This was a major, 'landmark' study carried out by IARC (a part of the WHO), which was intended to show once and for all that passive smoking was responsible for lung cancer in non-smokers.

Unfortunately for them, things didn't go according to the script:


ETS exposure during childhood was not associated with an increased risk of lung cancer (odds ratio [OR] for ever exposure = 0.78; 95% confidence interval [CI] = 0.64-0.96).

The OR for ever exposure to spousal ETS was 1.16 (95% CI = 0.93-1.44). No clear dose-response relationship could be demonstrated for cumulative spousal ETS exposure.

The OR for ever exposure to workplace ETS was 1.17 (95% CI = 0.94-1.45)"

Given the statistical rule that any OR confidence range that includes the value 1.0 means that the OR is statistically insignificant, and thus that the null hypothesis stands, what they really meant to say was this:

"There is no evidence that second-hand smoke causes lung cancer in non-smoking wives or work colleagues of smokers. However there is clear statistical evidence that children exposed to second-hand smoke are protected against lung cancer in later life, with the odds of getting LC some 22% less than those not exposed".

But hey, why let the truth be provided by a political incorrect conclusion?

When the WHO tried to - ahem - avoid reporting this study, the Sunday Telegraph got hold of it, and reported it under the (truthful) headine "Passive Smoking Does Not Cause Lung Cancer - Official". Those nice people at ASH tried to get the Press Complaints Commission to censure the ST. They failed - dismally!

WHO themselves swiftly followed up with a press release that screamed "PASSIVE SMOKING DOES CAUSE LUNG CANCER, DO NOT LET THEM FOOL YOU" (their capitals).

Yeah, right!

This was a black episode in the history of epidemiology - and also real science. This study never gets spoken of nowadays in all the blanket hysterical reporting of passive smoking lies.

Despite this outrageous attempt at censorship, most people still believe what the public health organisations such as WHO tell them.

Yet when it comes to spinning dishonest PC 'facts' out of statistics that clearly tell the opposite story, bastards like WHO could give lessons to Campbell, Mandelson and all.

BB said...

Sorry, not used to the tags here, so the link to the IARC study failed to appear. It is:

Budgie said...

Hormesis sounds similar to the mechanism already used in Enzyme Potentiated Desensitisation (EPD)

It is true for the poison mechanism that if you die (by drowning) in 10 ft of water you won't die (unless supremely careless) in 1 ft of water. But the allergy mechanism is different: with an allergy it is possible to "drown" in a quarter of an inch of water.

Unfortunately, until a layman experiences an allergy in himself or in someone close, there is a temptation to dismiss it as imaginary.

Frederick Davies said...

Concerning on how low levels of a pernicious agent can be beneficial, you may find the Channel-4's documentary "Nuclear Nightmares" very interesting. It turns out that no-radiation environments actually harm human health. The positive link between radiation and mortality has been established for high levels of the former, but low levels (like those we all live in throughout our lives) actually keep our immune system active.