Why We Age – the theories

Ok I get it. When most of us see the word ‘theory’ some hidden inner science lesson switch seems to go ‘clunk’ and we begin to feel our eyeballs  glaze over faster than a skating rink at the winter olympics. But seriously, without trying to put you all into a jargon induced coma there are very good reasons for understanding at least some of the current prevailing theories in gerontological science on why we all actually do age. Why you might well ask? Well primarily because understanding what may cause us to age will pretty likely lead us bang up to the very possibility of being able to interact with the mechanism/s of aging itself, right? And secondly if you have some real clarity on those mechanisms it might just help you to understand a little better whether you’re being fed a bunch of sciencey sounding marketing hogwash … or not! But before you all rush off and get your microscopes and pipettes dusted off in your quest for that old holy grail perhaps it’s best we get a little more perspective on what this might all mean.

Just as we heard in the last Why We Age? post, there’s no outright winner in the ‘Is it a disease or not?’ hypothesis, well the same appears to be the case in these murky waters as well. Much as we often like to think of science as being able to deliver clear and resolute answers, unfortunately we humans are a complicated bit of kit and trying to pin down absolute answers to questions related to our inner mechanics can be as easy a task as herding cats. In the complex realm of human biology and perhaps even more so in the study of the mechanisms of aging, the best we have at the moment is theory and that in the words of a man who had a few himself, a certain Mr Albert Einstein, means

‘In theory, theory and practice are the same. In practice, they are not.’

That said even though the best answers we’ve currently got are calculated guesses, these guesses are nonetheless based on some very convincing if not at times apparently conflicting research.

In the red corner we have what might be called the Programmed Aging Theories. This is a pretty self-explanatory bunch and there is a fair body of evidence to demonstrate that in a number of living species there exists a kind of self-destruct timer usually set to go off sometime after reproduction.

Salmon, for example, straight after the spawn release a veritable tidal wave of corticosteroids which trigger a process known as phenoptosis, a term quite literally meaning ‘their own pre-programmed death’; and even processes closer to home such as cancer, osteoarthritis and vascular disease are put forward as examples of the very same transactions in we humans. At a cellular level another process known as aptotosis refers once again to a preprogrammed death, but this time it’s of damaged, mutated or ‘sick’ cells. All multicellular critters do it and it’s estimated that we lot in particular lose anywhere from 50 to 70 billion cells each and every single day to aptotosis, and in fact insufficient amounts of this vital house-keeping are suspected to be behind to the rapid proliferation of cancer cells leading to metastasis and the uncontrolled tumour growth associated with later stage cancers.

One of the other areas connected to the programmed aging theory is that of telomeres. Telomeres are sections at the end of each of the DNA helix  which shorten each time the cell divides. In 1961 the leading biogerontologist Leonard Hayflick published the stunning finding that there was a direct correlation between cell age and telomere length, an announcement which consequently lead to an explosion in yet ever more theorising that perhaps by finding ways of keeping telomeres nice and long and shiny we would equally be doing the same with our own chronological age. Ah the simple fix.

And though the correlation between longevity and the Hayflick limit is these days taken as accepted fact, let’s not forget that even Hayflick himself doesn’t currently seem to see  any single magic bullet to turning back time and we can extrapolate that artificially extending telomeres is part of that conclusion. In his own somewhat academic words (watch those eyes!),

‘The finite lifetime of cultured, normal human and animal cells, is a reflection of the maximum capability of that cell lineage to replicate, which is … never reached, in real life because the aging process will kill the individual well in advance of that maximum number of divisions.’

I find this fascinating logic as it appears here that to Hayflick, the aging process is somehow distinct and separate from longevity itself.

Yet another complicating reason is simply that within us immortal cells do in fact already exist. They’re one’s that express an enzyme called telomerase which appears to extend the telomere and hence prolong, apparently indefinitely, the cell’s existence. But before you all rush out for few boxes of telomerase, unfortunately these so-called immortal cells are also ones more commonly known to us as cancer cells. Cells which carry clearly harmful mutations but which equally proliferate wildly throughout our bodies when unchecked by, among other processes, apoptosis or a fully functioning immune system. So can you see how when we’re messing about with the sheer complexity of this human machine, even the possibilities we uncover so often simply raise even more questions? Extend the Hayflick limit and possibly shorten your own (limit that is) rather than the other way round.

And now in the blue corner we have what we could call the Accumulated Damage Theories – or what is in the scientific lexicon called the Stochastic Theory. This side puts forward the notion that over time the physiology just keeps acquiring more and more damage at a rate in excess of the body’s equally miraculous self-cleaning and repair mechanisms. Over time the rate of damage simply becomes overwhelming, the immune system breaks down and all those nasty diseases of older age simply track us down and take us out like a pack of hungry wolves.

In their terrific 2001 bestseller The Quest for Immortality, Professors Jay Olshansky and Bruce A. Carnes liken the body to a car. One designed to carry its passengers – in this case our genetic material – only really as far as it needs to go. After all over-engineering, whether mechanical or biological means adding lots of extra bits and extra bits cost. Why else do you think Ikea have just the right amount of doodads in each of those handy packs?

To Carnes and Olshansky,

‘The scientific view is that aging, sickness and death are inadvertent by-products of operating living machines beyond their warranty period.’ (1)

So in this camp, breakdown is a sad but logical inevitability. However, Olshanky’s sparring partner from the last blog, Aubrey de Grey believes this simply means we can just send the old bag o’bones to the shop and have it lubed, waxed and a new set of plugs – clean out all the mess and start it all again from scratch so to speak. His somewhat controversial but academically credible SENS program (Strategies for Engineered Negligible Senescence) has evolved into a worldwide research foundation leading the charge into what they call ‘rejuvenation biotechnology’.

In the Scientific American of December 2008 three academic titans of gerontological academia published an article to accompany a recent joint announcement by 51 leading researchers starkly and unequivocally countering what they saw as the wildly inaccurate and misleading claims of many of the newly minted anti-aging entrepreneurs. The warning: ‘no anti-aging remedy on the market today has been proved effective.’

In the article the authors, being Olshansky and Carnes alongside the Biggest Daddy heavyweight of them all, none other than Professor Leonard Hayflick himself, jointly stated,

‘… we think of aging as the accumulation of random damage to the building blocks of life—especially to DNA, certain proteins, carbohydrates and lipids (fats)—that begins early in life and eventually exceeds the body’s self-repair capabilities. This damage gradually impairs the functioning of cells, tissues, organs and organ systems, thereby increasing vulnerability to disease and giving rise to the characteristic manifestations of aging, such as a loss of muscle and bone mass, a decline in reaction time, compromised hearing and vision, and reduced elasticity of the skin.’

So that pretty well clears up that side’s point of view then – and now we just gotta pick a side, right? Well as we’ve already heard apparently nothing’s ever that nice and simple in the mucky world of human biology. Firstly as we learnt at the outset this is all about theories, remember? And to turn once again to Professor Hayflick,

‘Virtually all theories of aging suffer from one important difficulty: any proposed cause of aging may, in itself, be the result of some more fundamental cause…Today, most biogerontologists believe that there is not a single cause of aging but many causes and that several mechanisms may be operating simultaneously.’ (2)

And here we land, in the words of the great man himself, perhaps closer to the heart of the issue than any polemic can ever be: that most likely it is a mix of all of the above. Which, of course, means finding any single on/off switch or any magic pill or potion a pretty far-fetched notion indeed. Doubtless this is the very central reason why all those 51 leading scientists decided to stick their heads above the parapet of anti-aging hyperbole. Well that and the fact that many of those very same researchers had been horrified to learn that their own studies were being erroneously touted about as justification and proof of magic and miracles galore by the anti-aging marketing machine.

So just as it seems clear that the answer to ‘Why We Age’ is most likely multifaceted, so too is it why any response should be the same. Clearly science is moving us ever closer to some extraordinary possibilities in the field of aging, health and longevity but as we’ve heard not one of those credible researchers is touting any magic pill … at least just yet.

Finally also bear in mind that simply fixing up the machine is only ever going to be one aspect of any real solution. The analogy of we humans to machines (or cars) totally sidesteps the importance to all aspects of health and wellbeing of areas such as emotional and mental health, strong supportive relationships and vibrant, positive inner worlds. Let’s be honest the Honda sitting in your drive doesn’t give a tinkers cuss whether it’s happy or not or feeling alone but the same inner journey in we humans has been consistently proven to lead to disastrous health outcomes. Grow Young is all about 360° health. Ignore at your peril!

 

1) The Quest for Immortality  S J Olshansky & B A Carnes   loc 2630

2) How and Why We Age  L Hayflick pp227

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