In the last Longevity Meme Newsletter I offered the following opinions on Protandim, current research into tuning the human metabolism and other longevity-related tinkering:

It is somewhat frustrating to watch well-oiled publicity machines going to work to promote what is essentially useless junk in the grand scheme of things. There is some moderately interesting science in the intersection of metabolism and longevity at the bottom of all this, but it's not science that will deliver firm answers or meaningful progress any more rapidly than the folks currently working - from a far more sound scientific basis - on calorie restriction mimetics. It certainly won't deliver any surety in whatever bottled compound they're selling today.

As I've remarked before, the whole field of metabolic science is useful, but any healthy life extension to come from it will be a form of tuning the machine - using better motor oil, running the engine at the most efficient speed, that sort of thing. This suffers from much the same problems as supplementation - you can spend as much time and money as you like tinkering and experimenting ... are you ever really sure you are making progress? Is it a productive use of your resources once you have gone past the basics?

Ian Clements wrote to me with the following comments:

This has, for me, highlighted the two differing models (which are not necessarily mutually exclusive) which may be a source of confusion: on the one hand, we may already be immortal, but are held back from achieving this by a myriad of successive minor failures of our body system; on the other, we have already more or less reached our natural life-span limit with our traditional living methods, and therefore need a radical alteration (growing replacement organs like lizards; reversing the present gradual decline of complete replacement of failing sub-systems).

It is not clear (to me anyway) which of these models more correctly describes us (or any living organism for that matter).

If the former, let's call it Model A, is true, then addressing each and every issue as it comes up or for which new solutions are found may well enable us individually live longer and the average life span to increase. This approach appears to be the one which has worked for the last 100+ years, and explains the data of a linear increase of the numbers and percentages living beyond 100 years. Model A is probably the one most of us use at present in practice, as we incorporate each successive proven (or plausable) new method and life-style alteration (regular exercise, not smoking, anti-oxidants, etc).

Model A was/is based on the belief that we can extend our healthy life up to an implicit maximum, but not extend beyond that - this last phrase is the one I now wish to challenge (implicit in its turn, byt the linear extension of lower mortality rates beyond about 80). However, we can revise our view of Model A (to the status of Immortality model): that is, immortality can be achieved by incorporating (cautiously) each and every proven improvement as they come along and therefore (perhaps) stay ahead of the ageing processes otherwise taking place.

The additional (Model B) idea recently introduced is the lure of immortality by some radical new methods - such as growing new organs from our existing cells (as distinct from transplants) to replace failing/ageing ones. I also put CR mimetics in this class, as this would probably require a lifelong intake of some drug to cause our cells to do the mimicing.

One of the benefits of age is that you get experience of many things, as distinct from just reading about them. And one of the things I've become increasingly convinced about is that gradual change/evolution is more successful than radical or revolutionary change. As a scientist, I have an open mind and will let the evidence decide; but until that happens (either way), I'll use the step-by-step approach to life extension (as, I'm sure, most others will). What I am highlighting here is that there needs to be a more explicit recognition of the two alternative models, and to be aware that Model B is not the only game in town - that Model A should not be either dismissed or consigned to the band-aid category; it just might be the only one that works.

Thus, far from tinkering being only a process of minor improvement whilst awaiting the Holy Grail of a radical complete solution, it (Model A) may be the only solution. If so, then far from needing to get started on anti-ageing research, we are already within the midst of it - after all, doubling the average age of death (well, 25%-50% if we ignore the distortion of including the under 5s mortality figures) in a hundred years is not to be sniffed at; couple that with the healthier old and linear improvements in mortality figures above 75 or so for several decades indicates that Model A has 'legs'.

Immortality in these comments refers to physical immortality, a state of "vulnerable agelessness."

I think I could assign all valid scientific efforts to extend healthy life span to the category of gradual change - but some gradual change is faster than others. No-one is claiming that Aubrey de Grey's Strategies for Engineered Negligible Senescence (SENS) could happen overnight; advances would be gradual ... but I see such work as more effective on a per dollar investment basis than working with supplements and metabolism. As is pointed out above, it's not a zero-sum, mutually exclusive sort of choice, however - in fact, everything that is not SENS is pretty well entrenched in the private and public research communities already. It's just that the resulting - largely incidental - gains in life span are not enough, and show no signs of accelerating rapidly. We need to add further, better strings to our bow if we want to avoid the consequences of untreated degenerative aging.

Posted by Reason