In the past few years two ongoing studies of long term calorie restriction (CR) in primates have started to publish their results on longevity. Both research programs have been underway for more than 20 years, one run by the National Institute on Aging and the other by the University of Wisconsin-Madison. Researchers have followed small groups of rhesus monkeys to see how the benefits to health and life expectancy resulting from a restricted calorie intake compare with those obtained in mice and other short-lived species. At this point the results are ambiguous, unfortunately: one study shows a modest gain in life expectancy that has been debated, while the other shows no gain in life expectancy, and that result has also been debated.

Calorie restriction does produce considerable benefits in short term measures of health in rhesus monkeys and humans, that much is definitive, but the present consensus in the research community is that it doesn't greatly extend life in longer-lived primates - perhaps a few years at most in humans. Differences and issues in the two primate studies mean that effects of this size on longevity may never be clear from the data generated. Other factors will wash it out, such as differences in the diet fed to the control groups, or the different age at which calorie restriction started. Certainly the results so far support the conjecture that calorie restriction is exceedingly good for health but doesn't have the same impressive effects on longevity as it does in short-lived animals. Why that is the case is a puzzle to be solved - but not one that has a great deal of relevance to the future of human longevity. One would hope that we'll be a long way down the road to rejuvenation therapies by the time another set of better constructed primate studies are nearing completion.

You'll find a long article over at the SENS Research Foundation that examines the NIA and Wisconsin primate studies, their differences, and their results in great detail - but I'm just going to skip ahead and quote some of the conclusions:

CR in Nonhuman Primates: A Muddle for Monkeys, Men, and Mimetics

In this post, I have sketched out in detail two major possible interpretations of the disparate mortality outcomes in the NIA and WNPRC nonhuman primate CR studies. The "Diminishing Returns" hypothesis posits that the health and longevity benefits of "CR" reported in the WNPRC study were merely the unsurprising results of one group of animals being fed a high-sucrose, low-nutrient chow on a literally ad libitum basis, and another group being kept to portions of that diet low enough to avoid the deranged metabolisms flowing from obesity and (possibly) fructose toxicity. In this interpretation, the more severe restrictions of energy intake imposed at the NIA - particularly when the chow to which access was restricted may have been healthier to begin with - led to no further health benefit, because there are none to be gained: the dramatic age-retarding effects of CR observed in laboratory rodents and other species do not translate into longevous species such as primates, and the sole benefit of controlling energy intake is avoidance of overweight and obesity.

The "Dose-Response" hypothesis begins from the same interpretation of the WNPRC study, but posits that far from being excessive (or, at best, superfluous) to that required for good health, the additional energy restriction imposed at NIA were too little, and imposed during too narrow a window, to elicit a clear signal in health and lifespan benefits; this is supported by the evidence that the NIA primates were not especially hungry, and only weakly and inconsistently exhibited improvements in risk factors and endocrine signatures of CR that are seen both in life-extending CR in rodents, and in humans under rigorous CR.

Unfortunately, it seems very unlikely that this question will be resolved. Even the narrow question of whether the age-retarding effects of CR in laboratory rodents translate into nonhuman primates could only be established with confidence after yet another trial in nonhuman primates. [Such] a study is extremely unlikely in light of the enormous expense of the first two trials, disappointment (and possibly embarrassment) with the results, [and] the ill winds for nonhuman primate research. [Even] if such a well-designed and well-executed study were initiated: what then? Supposing that support were maintained for the duration of the experiment [it] would be a further three decades before the earliest point at which survival data could be reported.

The timescales involved in resolving these questions cannot be reconciled with the immediate imperatives that drive us to pose them. With the scale of the humanitarian, economic, and social crisis that looms in the coming decades due to global demographic aging and associated ill-health, the near-term need for effective interventions against the aging process could not be greater. Whether CR can retard aging in nonhuman primates or not; whether it can retard aging in humans or not; whether even effective CR mimetics can somehow be shepherded through clinical trials - even the most optimistic projection for retarding aging through such approaches is inadequate to the needs and suffering of aging world.

The point made in the article is the same one that should be made for all means of slowing the pace of aging by altering metabolism, whether by the use of drugs to replicate some of the changes caused by calorie restriction or via other mechanisms. These are very difficult and challenging projects, certainly very expensive in time and funds, and which will produce poor and uncertain end results even if successful. Ways to modestly slow aging do nothing for people who are already old, and we will grow old waiting for success in the development of drugs that can safely tinker our metabolisms into a state of slower aging.

The better approach is that outlined by the SENS Research Foundation: targeted therapies to repair the known forms of cellular and molecular damage that cause aging. This path is cheaper, more certain, and the resulting therapies will be capable of rejuvenation - of reversing degenerative aging, not just slowing it down a little. They will be greatly beneficial for the old, and extend the length of life lived in health and vigor. This is why I say that calorie restriction studies are irrelevant to the future of our health and longevity: the only thing that really matters is whether or not the SENS vision or similar repair therapies are prioritized, funded, and developed.

We'll take a short excursion into ranking futurists for today, prompted by a recent article that offers a (transhumanism-slanted) opinion on the identity of the most important futurists of the past few decades.

The Most Significant Futurists of the Past 50 Years

Our visions of the future tend to be forged in the pages of science fiction. But for the past half-century, a number of prominent thinkers, activists, and scientists have made significant contributions to our understanding of what the future could look like. Here are 10 recent futurists you absolutely need to know about. Needless to say, there were dozens upon dozens of amazing futurists who could have been included in this article, so it wasn't easy to pare down this list. But given the width and breadth of futurist discourse, we decided to select thinkers whose contributions should be considered seminal and highly influential to their field of study.

Those selected include Robert Ettinger, one of the founders of modern cryonics, and Aubrey de Grey, who presently works to make his SENS roadmap to human rejuvenation a reality. Ray Kurzweil is notably absent from the list.

It isn't mentioned as a selection criteria in the article, but I think that ranking the importance of futurists by how effectively they help to create the future that they envisage isn't all that bad of an idea. Advocates and popularists play a needed role in moving from vision to reality, but progress also needs people to perform and orchestrate the actual work of research and development. Kurzweil, for example, is a popularist and an advocate with respect to his futurism: beyond the books and films and persuasion his day job as an inventor and entrepreneur is so far largely irrelevant to the future he envisages. I don't think anyone can argue that he isn't important in the arena of ideas regarding machine intelligence, accelerating change, and how this will all play out in the decades ahead. But how much more important would Kurzweil be if, for example, he had decided a decade or two back to create a company like Zyvex as a long term play to advance molecular manufacturing, or something equivalent in AI work?

In contrast Ettinger and de Grey both founded successful organizations devoted to realizing their particular visions: the Cryonics Institute and the SENS Research Foundation. Both were instrumental in creating the groundwork and the early community of supporters to enable a new industry and branch of research in applied medicine. That seems like the best approach to futurism to me: not just persuasion, but also working to create the change you want to see in the world.

If you visit Fight Aging! on a regular basis you'll know that I strongly favor the SENS Research Foundation and the approach taken by its founders, advisors, and staff to speed the development of human rejuvenation. I think we could do with another ten or twenty similar organizations, and certainly a hundredfold increase in the funding for rejuvenation research, but right now we have just the one. So send the Foundation a donation if you're feeling flush today, because there's no-one else out there at the moment who can do as much for your future longevity with that money.

Or rather I should say that there are dozens and possibly hundreds of people out there who can do as much for your future longevity with those funds - it's just that you don't know who they are. Would you know enough to chase down William Bains in the UK and ask him to work on AGE-breaker drugs for glucosepane, for example? Or pick the group at the Buck Institute best placed work on ways to selectively destroy senescent cells by interfering in their characteristic biology? Or have Janko Nikolich-Žugich in Arizona work on restoring the aged immune system by removing unwanted T cells? Of course not. But there is a whole world of researchers out there with useful specialist knowledge and who are these days quite willing to work on the foundation technologies needed for human rejuvenation - provided that the funding can be found.

Organizations like the SENS Research Foundation are the interface between you and the research community: the Foundation staff provide domain knowledge and relationships needed in order to direct funds effectively. Without their work it would be impossible for folk like you or I to help make this field of science move faster - we wouldn't know where to start or who to talk to, never mind where to send funds, and finding out would be so costly in comparison to what we could donate as to make the whole exercise pointless.

The SENS Research Foundation is the watering hole, not the herd. It is the gateway, not the city. It is the door to a network of researchers who are interested in human rejuvenation, but that network is a greater and broader thing than the Foundation. I bring up this point because many people look no further than the gateway: they see the SENS Research Foundation and think of an enclosed group, off to one side of the scientific community, doing its own thing in isolation, and therefore easy to dismiss. For all that this point of view is absolutely incorrect, it is not uncommon. You'll see it liberally applied to biotechnology companies, noted laboratories, and other organizations that are also gateways to broader scientific networks. People look at an organization, see its staff performing some research work in its own domain, but fail to see beyond that to take in the great tree of relationships and connections behind the name plate.

The greatest achievement of the folk behind the SENS Research Foundation (and the Methuselah Foundation before it) is their construction of a lasting and growing network of supporters of rejuvenation research within the life sciences. This was quite the task over the past decade and involved a lot of persuasion, changing the culture of the research community to become more receptive towards longevity science, building relationships, holding conferences, and tireless advocacy. It is that web of relationships, and not the existence of the Foundation per se, that enables growth in funding and progress towards the goal of ending aging. As for all areas of human endeavor, it is relationships and networking that make the world turn: the Foundation is a mailbox, a guidebook, and a banner for a larger community, an outgrowth of that community even, and it is the community that gets things done.

This is worth bearing in mind, because it's all to easy to focus on organizations rather than people and thus miss the whole point of the exercise.

Telomeres are repeating sequences of nucleic acids that cap the ends of chromosomes in the cell nucleus and stop actual gene-coding DNA from being chopped off when a cell divides. The mechanisms of DNA replication require extra leg room at the ends of the strand, a trailing sequence that is not copied over to the new strand under assembly - and the primary role of telomeres is to be the part that is dropped on the floor. A little of their length is thus lost with every cell division. This shortening acts as a clock to count cell divisions, and cells with very short telomeres stop replicating - they either enter cellular senescence (which ideally then causes the immune system to destroy them) or destroy themselves directly via programmed cell death mechanisms.

Telomere length is more dynamic than this simple picture, however. In some cell populations, such as the various types of stem cell that maintain tissues and produce new cells to replace those lost or damaged, an enzyme called telomerase continually lengthens telomeres so as to allow a cell lineage to continue dividing indefinitely.

Ordinary, non-stem cell populations exhibit a range of telomere lengths, some short, some long. You might imagine that a population of cells replenished more frequently or recently by stem cells will have longer telomeres on average. A population that is receiving less support might have shorter telomeres. Researchers have shown that a higher proportion of short telomeres in white blood cells correlates well with ill health or stress, and somewhat correlates with age. Some more complex measures of telomere length, a step above just taking the average, have been shown to correlate well with age, however, and other techniques do a fair job of predicting future life expectancy in laboratory animals.

A few years back a brace of startup biotech companies were aiming to address aspects of aging by lengthening telomeres through the use of telomerase. None of that went anywhere, unfortunately, but it's possible that they were just too early - it is frequently the case that all of the first batch of companies in a new area of biotechnology fail. It's a tough business to be in. I was a skeptic at the time regarding their potential for success based on my expectation that telomere length will prove not to be a root cause of aging.

Nonetheless, researchers are demonstrating extension of life in mice through telomerase these days, but it is as yet unknown as to exactly why this works. Perhaps it makes stem cells work harder to maintain tissues, perhaps there is just one critically limiting type of stem cell or tissue that benefits from more telomerase, or perhaps it involves other effects causes by increased levels of telomerase that have nothing to do with telomere length. It is worth bearing in mind that there are considerable differences in natural levels of telomerase and the resulting telomere dynamics between mice and people, however. Telomerase therapy is probably not something you'd want to just up and try without the research community first obtaining a much greater understanding of why it works to extend life in mice.

Why? Well, the risk of telomere lengthening in humans is cancer. Any mechanism that globally, or possibly even narrowly, extends telomere length in people will raise the risk of suffering cancer. The whole system of telomere dynamics and cellular senescence is intimately tied to the processes of cancer suppression, while all cancers evolve ways of lengthening their telomeres to allow unlimited cell division. Boosting your telomerase levels looks a lot more risky to me than, say, undergoing first generation stem cell transplants.

There continues to be a lot of activity in telomere research and development. The present brace of telomere-related biotech startups are commercializing ways to measure telomere length rather than extend it. The products are tests that will at first add another measure to inform patients on the state of their health, then possibly act as an effective biomarker of biological age, and perhaps later prove useful in further research if it turns out that telomerase-based therapies can be beneficial in humans.

How Long Will You Live?

A growing number of researchers say telomere length is a critically important indicator of how old we really are, and of how many healthy years we may have in front of us. A new industry is sprouting up around the science of longevity, offering telomere testing to the public - and Nobel laureate Elizabeth Blackburn is a notable part of it. Her company, Telome Health, is set to launch a telomere test later this year, joining a handful of others that already do. Like a cholesterol or blood-pressure test, telomere testing could one day become standard in doctors' offices.

And maybe in the future, we'll be able to slow or reverse the effects of aging -the vision of researchers searching for ways to boost telomerase, a goal already achieved in lab mice. Some are already marketing so-called "telomerase activators" to a public hungry for ways to stop the clock, although no such drugs have been approved. With so many companies rushing to come on board, "there's a lot of weird stuff going on out there," cautions Jerry W. Shay of the University of Texas Southwestern Medical Center, an expert on cell biology and telomere length.

Certainly you should be looking askance at any group that's selling herbal "telomerase activators" - it's the standard garbage from the supplement marketplace, and sadly that's the place that formerly funded companies doing original research often end up. It's hard to make money doing something useful in medical research, but depressingly easy to make money doing something useless in the supplement business. The traditional model here is to grab a little research that's somewhat relevant, scare up a bunch of Chinese herb extracts, and then hope that if you market the thing hard enough it'll overcome the obvious ineffectiveness and pointlessness. If you can buy out the shell of a company formerly doing research to try to profit from its one-time reputation, then all the better. Caveat emptor is the watchword, as ever.

So where do telomeres fit in the taxonomy of cause versus secondary effect in aging? Because of the dynamic nature of telomere length I'm given to think that it's a secondary effect: get sick and average telomere length in white blood cells shortens; get well and it lengthens again. This sounds very much like a system responding to circumstances, and those circumstances most likely include the general level of cellular damage, inflammation, and metabolic waste products - all of which grow with age. As for so many other similar questions about aging, the fastest and cheapest way to answer this question about telomere length is to implement the Strategies for Engineered Negligible Senescence (SENS): build the biotechnologies to repair these forms of damage and then see what happens to telomere length once its done. That is a good deal easier at this point than obtaining a full understanding of the aging of human biology.

None of the above precludes short telomeres from causing further damage or changes of their own, of course. Aging proceeds as a cascade of harmful effects as damage causes further damage and flailing biological systems cope badly with the new circumstances they find themselves in. Here is a recent article on how telomere length can impact gene expression and thus the operation of metabolism in a previously unsuspected way, for example:

Telomeres Affect Gene Expression

DUX4, a gene responsible for the genetic disease facioscapulohumeral muscular dystrophy (FSHD), is normally silenced because it sits next to a telomere - a protective DNA sequence that caps the ends of chromosomes, according to [a recent study]. But as telomeres shorten, as they do with age, DUX4 expression climbs, which may explain the late onset of FSHD. Another gene, called FRG2, which sits 100 kilobases away from the telomere, is also affected by telomere length.

"This was completely unexpected. We think that DUX4 and FRG2 are the tip of an iceberg." Due to shrinking telomeres, many genes might gradually become more active as we get older, which may be important for several diseases of old age. "This represents a very significant general advance in our understanding of how telomere shortening may affect human biology."

"Cui bono?", "to whose benefit?", is a question that should never be far from mind. It is rarely the case that the loudest threads in our grand, connected cultural conversation represent the best, the most useful, or the most virtuous of what is possible. That is just as true in any subculture as it is in the mainstream: follow the money and much becomes clear.

Longevity hotspots might not be a term familiar to you, but Blue Zones might be thanks to a fair degree of publicity for that latter term. They mean the same thing, but the latter is a brand rather than a description. A small industry associated with this brand is devoted to promoting the idea that some parts of the world exhibit pockets of exceptional human longevity. It is convenient for various businesspeople to act as though this is proven beyond a doubt and that the root causes involve aspects of local culture, diet, and lifestyle that can be packaged up and sold. So the world goes on: this sort of thing is a textbook example of how small science projects on minor aspects of human longevity can spawn commercial monstrosities set on muddying the waters, promoting myths, and profiting from the credulous.

It is by no means certain that longevity hotspots exist in actuality, or at least not in the sense that Blue Zone business ventures would like you to think, but those most interested in carrying on a dialog on this topic - i.e. marketing folk involved in tourism, diet, lifestyle coaching, and so forth - don't really care to hear that message. Nonetheless:

Designating longevity hotspots: cautions concerning the instability of per capita centenarian estimates

Estimates of per capita centenarians in a Utah population varied between one per 12,864 and one per 4,675, depending on the data that were used, the population assumptions that were made, and the boundary limits that were employed. In general, caution is warranted in claims about the existence of longevity hotspots.

Performing any sort of statistical study on human populations in a given geographical area, even on something as apparently simple as age, is enormously complex. People move and data is ever incomplete or outright false. Some locations attract the wealthy in large numbers, a demographic already well correlated with greater life expectancy. When a region in the US with good demographic data can produce a threefold range of results for a simple population question, one has to wonder about the accuracy of other studies - and the smaller the group the less helpful that statistical procedures become.

This is not to say that there is nothing to be learned by comparing different populations with different lifestyles, but I would be extremely surprised to see the end results be anything other than additional support for the value of exercise and calorie restriction (and derived measures such as body mass index). These line items strongly correlate with health in large statistical studies.

Neither exercise nor calorie restriction will let you reliably live to see 100, however. The only thing that can achieve that goal is significant progress in new medical science. Longevity hotspots are, like so much of what is discussed in relation to aging these days, nothing but a sideshow - something that occupies time and energy and attention, and all to no good end. That the data is most likely flawed and what little science there was is now largely buried beneath an industry that strives to make money by promoting magical thinking and ignorance just makes the joke a little more black.