Denial of Death or Denial of Immortality

At year end, I have a tradition of writing a column more speculative and personal than usual.  In this post, I consider critically the standard physicalist belief that our consciousness depends on a physical brain, and hence death is the end of all awareness. 

I was 46 years old when I first considered the question, what is aging and where does it come from?  Before that, I had been a physicist with diverse scientific interests pretty much all my life. What was I thinking?  Why had I never considered this topic before? I think the answer is: fear.

Ever since I can remember, I’ve been interested in preserving my health and extending my life.  But it was several years into a committed study of aging science that I thought to ask, why? Do I love life especially well, or am I afraid of death?

I’ve gradually come to realize that fear of death has cast a shadow over my thinking about aging, and possibly about many other other things as well.  I was a young child when I taught myself to avoid thinking about death because I couldn’t handle the abyss of terror into which my thoughts spun. As I developed the habit of tiptoeing around thoughts and discussions of death, what was I missing?  I’ve come to think that whole areas of my humanity became occluded, and have only begun to re-emerge in recent years.

In 1972, Ernest Becker wrote a book called The Denial of Death, which I knew even then that I ought to read.  I bought it, but years went by and it never made it remained unopened on my bookshelf.  Becker proposed that all of human civilization—art and literature, architecture, music, settlements and empires, stories of heroism, religious teachings, projects great and small—all of it stems from a drive to compensate for our mortality by creating something more permanent than our physical selves.  Even if this is only a little true, we have to wonder: Who would we be if we weren’t trying so hard to avoid death?

The Bhutanese people are reputed to be the happiest in the world.  Their mountains are majestic, their lifestyle modest and close to the land; but in this they are no different from many nations whose people seem to be pitiable.  So what is their secret? Eric Weiner tells us that their culture is steeped in death rituals, and that death is out in the open in Bhutan.  Bhutanese Buddhists contemplate their own death five times a day. Weiner goes on to cite studies that suggest thinking about death makes us more joyous.  These studies wouldn’t convince anyone, unless they wanted to be convinced. Maybe I want to be convinced

Of course, Buddhism is pervasive in Bhutan, with its belief that our souls cycle through birth and rebirth in karmic cycles.  Death is not a final end. The abyss that terrified me is not part of their belief system. I used to try consoling myself with such possibilities, but I got nowhere.  This is not science, it’s wishful thinking. Religions have manipulated people with promises about life after death since the dawn of human civilization. I’m too smart to be deceived with such fairy tales.  Even if it makes me afraid, even if it paralyzes me with terror, I prefer the realism of science.

But there came a point when it occurred to me maybe that the immortal soul was the reality and the fear was the delusion.  Did I believe in the Great Void just so I could feel smarter than people who believed in heaven? I peeked out from my fear just enough to question whether the abyss was a scientific deduction, or merely an artifact of scientific culture. Science or scientism?

But there came a point when I wondered whether the self-delusion was in the belief that it was all wishful thinking.  I peeked out from my fear just enough to question whether the abyss was a scientific deduction, or merely an artifact of scientific culture. Science or scientism?

Let’s backtrack to a different scientific myth.  We have been effective in reversing the scientific prejudice that says human lifespan is a fixed, unalterable fact of our biology. Given the intellectual bankruptcy of this thesis, why would so many people, scientists especially, have embraced it for so long?  One reason is the experience with being disappointed by charlatans, fooled by mountebanks, alchemists and snake-oil salesmen who have profited from their customers’ willingness to believe. Perhaps a larger reason is the fear of death that they have walled off with a kind of despair masquerading as science.  Hope is often more frightening than despair. As Milton wrote, “So farewell hope, and with hope farewell fear.”

They leave their hope behind so they don’t have to face the discomfort of their fears.  We have exposed their unreason.

Now, I wonder if we have been drawn into the same dynamic: that we have relinquished a hope that is too uncomfortable to carry.  The hope we have relinquished is that the “self” persists in some form and awareness continues after physical death. For most of my life, I believed that physical reality is the only reality there is, that anything I feel as a “self” depends on 100 billion neurons and a blood supply.

And yet, my primary experience, the only thing of which I am truly certain, is that I exist as a point of consciousness, a primal self-awareness that all our science (as Chalmers has pounded home to us all) is powerless to explain.  Many of us believe (with Dennett) that, since physical reality is the only reality, this primal self-awareness must be an epiphenomenon of neural activity in the physical brain—some would say an illusion created by computation. Maybe this is true, but there is no scientific support for this statement, nor does scientific evidence weigh against it.  The statement that our feeling of self derives from computation is an article of faith, or of Scientism, rather than anything for which we can adduce evidence.

And for me, this idea is counter-intuitive.  I have a meditation practice. I have studied astrophysics and quantum mechanics.  I go for long walks in the woods and I allow my mind to run all over such topics, and the result until now has been for me to trust this feeling of selfhood more than I trust any reasoning about an alleged physical basis.  The light of my awareness is a truth unto itself.

“Yeah, yeah,” says my scientific training, “where’s the evidence?”  Evidence there is aplenty, but it is ignored by the scientific mainstream.  Some of it is recognized as anomaly that we will understand someday, even though it seems strange now.  The more direct kinds of evidence are actively suppressed, banned from mainstream scientific journals and exiled to the Journal of Scientific Exploration and other publications of mixed quality, where it takes some patience to separate the wheat from the chaff.

In the former category are some of the anomalies cited at the beginning of the Michael Levin video that I reported on last week.  Caterpillars whose brains are literally dissolved in morphing into a butterfly, and yet memories survive.  Monarch butterflies that pass memories about the route to return home over half a dozen generations. Ciliated protozoa that are capable of learning and memory, though they have no nerve cells.  People who develop a musical ability or an interest in motorcycles or a vegetarian conviction when they receive a heart transplant.

In the latter category are a number of experiments for which the best source might be Dean Radin’s books, for example Entangled Minds and The Conscious Universe.  There are near-death experiences, in which people have memories, often blissful and love-filled, from the time when there was no neural activity in their brains.  Reflexively, the scientific rationalists dismiss these reports as fantasy creations of the oxygen-starved brain. But in many cases, the person recovering from an NDE reports things she would have no way of knowing if she had not been conscious during the time she was clinically dead.  My introduction to NDE science was by Pim van Lommel. His latest book is Infinite Awareness.  Similar stories have been collected by John Hagan, Chris Carter, Eben Alexander, and others.  Finally, there is the scientific study of reincarnation, pioneered in the West by the late Ian Stevenson, professor of psychiatry at University of Virginia.  His work has been continued by Jim Tucker at UVa and Raymond Moody (his book), Roy Stemman, and others elsewhere.  Carol Bowman researched and documented one spectacular case of a Louisiana couple, non-religious skeptics, whose 2-year-old son had persistent nightmares, then displayed uncanny knowledge about the crash of a World War II fighter plane in Iwo Jima.

photo of James Leininger as a child

Why does the mainstream scientific community persist in dismissing all this research without evaluating it?  Because it conflicts with a strictly-materialist, “scientific” world-view formed in the 19th Century, when the world of science was suffering under the delusion that every natural phenomenon might soon be explained by deterministic laws.  A few decades later, quantum physics put that aspiration to rest, and offered a mechanics at the foundation of science that has room for mind, for intention, for Cartesian dualism, for those who see fit to interpret quantum mechanics in that light.  Quantum mechanics may be 90 years old, but the scientific world has yet to absorb its message.  In particular, it has been shown in independent experiments by Radin, Jahn, and others that the events that are treated as “random” in QM can be influenced by conscious intent, without any recognized physical connection between the brain and the quantum system.  Furthermore, this connection is stronger when there is an emotional stake in the outcome, and its force increases non-linearly with the number of people whose attention is focused on a quantum target.

My tentative conclusion from this is that there is room within what quantum mechanics treats as “random” for (non-material) mind to influence material reality.  And there is evidence from experiment and anecdotes that this actually occurs.  Hence, the door remains open for a non-material locus of selfhood, or some aspect thereof.

“Despite the unrivaled empirical success of quantum theory, the very suggestion that it may be literally true as a description of nature is still greeted with cynicism, incomprehension, and even anger.”   — David Deutsch


The Body Electric

Aging is an extension of the developmental program into a phase of self-destruction.  This much has become clear (if not yet uncontroversial) over the last decade. But this insight is of little use to us so long as developmental biology is so poorly understood.  I have worked from a perspective in which development and aging are both driven by gene expression—an epigenetic program. Then, last week, I learned about an electrical dimension of developmental biology that is entirely new to me.  I’m grateful to Johnny Adams for pointing me to a recent Stanford lecture by Michael Levin, summarizing two decades of research from his Tufts University lab.  

Levin starts by contrasting the intelligence of an ovarian tumor (teratoma) with the intelligence of a tadpole under metamorphosis.  The tumor has stem cells that can create organ tissue, teeth, bones, and hair—but their placement is haphazard, and therefore without function.  The different tissues grow in every direction with no guiding logic or structure.

In contrast, the morphing tadpole knows exactly where it is going and what it wants to be when it grows up.  Levin cites experiments from the 1960s in which a salamander tail grafted onto the side of the body turns into a functional leg, complete with foot and toes.  In experiments in Levin’s lab, he moves an eye to the back of the tadpole head, and it migrates to its correct position as the tadpole becomes a frog.

Where is the information that tells the body how to form itself?  In what form is the blueprint for the body’s shape and structure?

“Very much like the brain, Somatic tissues form electric networks that make decisions.  The decisions are not about behavior, but anatomy.”

Nerve cells communicate by passing electric currents through ion channels and deploying neurotransmitters to pass electric charge from one cell to the next.  Somatic cells use these same mechanisms to communicate with each other and decide where to go, forming into tissues and structures in a functional body. Using voltage-sensitive fluorescent dies, Levin and his colleagues have visualized the electrical structures that precede and determine corresponding anatomical structures.  

This is radical.  It is a new and unstudied mechanism of biology.  Cells in a developing body are wired together electrically, and in their connectivity is encoded the structure of the body toward which they are aiming.  The electrical connections work very much the way nerve cells in the brain do, but their purpose is entirely different. And Levin emphasizes that the time scale is very different.  Electrical signals that make brains think and make muscles contract last for a few thousandths of a second. The circuits that code for bodily structure last for hours or days.

Extraordinary claims require extraordinary proof, and so Levin has been studying this system to manipulate it for almost 20 years now.  Recently, his lab has cracked the code sufficiently to manipulate development and regeneration at a level higher than biochemistry. They have worked with planaria worms and developing amphibians, two experimental models that are capable of regeneration.  They have experimented with rewiring the circuits, and now understand the system well enough to create two-headed worms and ectopic limbs on frogs.

The story of 21st Century biology has, thus far, been about gene expression.  The body is controlled by chemical signals, and these are produced on demand by masking and unmasking different portions of the chromosome, exposing the code for the proteins that are needed in a given cell at a given time.  Our activity and our homeostasis is maintained in this way from moment to moment, and I believe that our life histories, from development to aging and death, are also controlled via gene transcription.

Now comes Levin with a demonstration that, at least under some circumstances, there is a system upstream of gene transcription that is based on electric circuits.  The system controls development at a level higher than gene transcription. For example, an entire eye can be ordered up by artificially creating an electric pattern in the right place, and the eye will have all its parts intact and be functional.  They have placed eyes on a tadpole’s tail and demonstrated that the tadpole can see through them, and their brains can interpret the images.



Living fluids, within and between cells, contain dissolved salts in the form of positive (Na+, K+, Ca++, Mg++) and negative (Cl, PO43-, SO42-) ions, Cell membranes have pumps that can pump ions out of the cell selectively and ion channels that allow some ions through, but not others.  typically, the cell has more negative than positive ions inside, so it has a negative membrane potential, ranging from a few mV for blood and skin to tens of mV for nerve and muscle cells.  Rapid changes in membrane potential are the driving force behind muscle contraction and nerve firing.  

There are drugs that can affect membrane potentials by blocking ion channels selectively.  Membrane potentials have multiple signaling functions, most notably the potential has to drop close to zero before a cell can reproduce, and drugs that keep membrane potential high are able to inhibit cell replication.  There are proposed applications for cancer treatment (inhibiting replication) and for regeneration (promoting replication). Within cells, different organelles also have membranes and there are associated intra-cellular potential differences.  Mitochondria are the most negative parts of the cell, at about -140 mV.

DiBAC is a voltage-sensitive fluorescent dye that is used to visualize patterns of voltage variation in and around a cell. [ref]  Patterns within a cell show locations and activities of the organelles.  Patterns on larger, multi-cellular scales function like blueprints of development, and in animals that can regenerate, the patterns persist and guide later regeneration whenever limbs or organs become damaged.


How do they manipulate electric patterns experimentally, to demonstrate the effect on morphology?

This is not clear in Levin’s oral presentation, but an audience member asked the question.  It is not done with external electric voltages. It is done with biochemical modification of the gateways that control ion channels.  Levin drops a hint that there are photo-sensitive drugs that can control ion gates that can be used to translate a projected geometric image into a pattern of membrane potentials.  He argues that the patterns encode “blueprints” rather than a “construction manual”, based on the fact that the program is adaptive in the face of physical barriers and disruptions, and organisms are capable of detecting damaged parts and growing new parts to the original specs. Levin’s group has tampered with membrane potentials in order to guide the growth of nerve axons in regenerating tissue [ref].  This is just the beginning of the understanding that will ultimately be necessary to reprogram electric circuits to order for medical applications[ref].

In the Levin Lab publication list, there are 28 academic publications in 2018 alone.  There’s a lot here to absorb, and it’s all new to me.

Levin was a computer scientist before he was a biologist, and he continues to be fascinated by the ways in which cells in tissues outside the brain can act as logic circuits.  Gap junctions are bridges connecting adjacent cells, through which ions can flow, transferring charge.  This is the basis of electric circuitry that supports complex logic. A post-doc in Levin’s lab designed a computer simulation that can model the activities of gap junction circuits.  This paper from 2018 ALife Conference proceedings is a good introduction, with context and lots of references.


What does this have to do with aging?

I’m writing about this work more because I think it is potentially a paradigm shift, not because I think it has immediate implications for aging.  Still, because I am who I am and you are who you are, I include possible implications for aging science.

  1. Body parts become damaged with age.  Regeneration will probably be a necessary part of any long-term anti-aging program.  We’ve learned that robust regeneration is available in many invertebrates and amphibians, but it is switched off actively in mammals.  The mechanisms remain latent, untapped, and there are examples of turning them back on.  Bioelectric programming is a new avenue to explore for regaining control of mammalian regeneration.
  2. I believe that the developmental clock continues seamlessly into an aging clock.  The same timing mechanism controls both development and aging. If development is under electrical control, then we might find that there are electrical signal networks that trigger aging.  I’ve written to Levin to ask if he is looking into this.
  3. Some people in the anti-aging community are also interested in simulating the brain in a computer program, and they imagine that if my brain’s connectivity can be simulated in enough detail, the computer simulation will start to “feel like me”.  For people who believe that consciousness is a function of the brain, and that computer modeling of the brain provides a path to a sort of eternal life, Levin’s work may be sobering. Knowledge and information processing take place not just in the brain but throughout the body, and not at the level of neural circuits but at the level of molecules.
  4. The spirit of modern biology is the reductionist spirit of 19th century physics.  Levin argues that we have been remiss in not exploring ways in which living systems are organized from the top down.  I agree.

It is widely assumed in developmental biology and bioengineering that optimal understanding and control of complex living systems follows from models of molecular events. The success of reductionism has overshadowed attempts at top-down models and control policies in biological systems. However, other fields, including physics, engineering and neuroscience, have successfully used the explanations and models at higher levels of organization, including least-action principles in physics and control theoretic models in computational neuroscience. Exploiting the dynamic regulation of pattern formation in embryogenesis and regeneration requires new approaches to understand how cells cooperate towards large-scale anatomical goal states. Here, we argue that top-down models of pattern homeostasis serve as proof of principle for extending the current paradigm beyond emergence and molecule-level rules.  [ref]

A Speculation

In epidemiological studies, it has become clear that exposure to radio frequency radiation is associated with higher cancer risk [review].  There are anecdotal reports of people whose mental function is affected by wifi and by nearby cell phone towers.  Part of the reason we don’t know more about the subject is that the entire telecomm industry works behind the scenes to discredit and defund the science.  (I have found that the relevant articles are suppressed in Google Scholar and PubMed searches.) Another reason is that we have no theoretical understanding of how radio frequencies interact with living cells.  The standard biological paradigm regards living systems as chemical systems, and there are no obvious ways that radio waves at the levels we are commonly exposed should affect chemistry.  Interaction of radio frequencies with ion channels is a possible mechanism, and may open the door to understanding (and then minimizing) the hazard.  Most interesting is the effect of RF on mitochondrial potential, which may connect to an emerging paradigm that cancer has a mitochondrial origin. [Here’s an older reference from the 1980s. More recent ref. And another]

Letter to an Incipient Cancer Survivor

This is a letter I wrote to a dear friend from the 1970s who has been diagnosed recently with colon cancer.  She had surgery last summer to remove the primary tumor, and is in the midst of a 12-week course of chemotherapy.  She has, in my opinion, a well-balanced view of the relative merits of traditional vs alternative treatments. One unusual thing about her situation is that she has an extraordinary social support system, having led a community of peer counselors within the disability community for many years, and now benefiting personally from the community of people she has helped.

Dear M—-,

  We would like to be able to derive from the research on controlled clinical trials a “best bet” treatment option, but the data to support this inference don’t exist.  One reason is that only chemotherapy has been tested with controlled clinical trials, and for your particular brand of cancer, the odds that chemo offers don’t look attractive.  For alternative treatment modalities, we have only anecdotes and not controlled trials. Another reason is that cancer is an individual disease, more so than heart disease or infectious diseases.  Different people respond very differently, and the medical community has not yet figured out how to tell in advance which treatments will work for which patients.

   Western medicine profoundly misunderstands the nature of cancer.  The classical understanding is that cancer results from a series of random mutations as the body’s stem cells divide, culminating in some combination of genetic abnormalities that enable a single cell to evade apoptosis and all the body’s defenses against cancer.  In this paradigm, the root of the problem is in the DNA of the cell nucleus. But we know from experiment this is not true. When the DNA-nucleus of a cancer cell is transplanted into a normal cell, the normal cell remains normal, and when the DNA-nucleus of a normal cell is transplanted into a cancer cell, the cell remains cancerous [ref, ref].  I don’t pretend to understand the true cause of cancer, but I suspect it is related to the mitochondria at the cellular level, and to immune and other deficiencies at the system level that make the metabolism as a whole hospitable to cancer.

   When our bodies are healthy, cancer is nipped in the bud, probably as a frequent and routine occurrence.  Cancerous cells are induced to commit suicide (apoptosis) or they are marked out by the immune system and destroyed by white blood cells.  Cancer arises as a clinical reality only when the body fails to do this. Western medicine makes the mistake of focusing exclusively on killing the cancer, without attention to re-balancing the body or strengthening the immune system so cancer cannot recur.  In fact, chemo and radiation both damage the immune system, which you depend on to guard against a recurrence.

   I’ve heard some doctors say, and I believe it’s true, that all cancer treatment modalities rely in the end on your immune system to kill the last few cancer cells and to prevent recurrence.  When cancer recurs, is it because just one cancer cell managed to survive the onslaught of chemo, or is it because the immune system is so weak that the body is highly vulnerable to new instances?  It is an academic question, because in any case we need a healthy immune system to survive.

    At some point, our plan will be to switch over from killing the cancer to healing your body and restoring your immune system.  Maybe we’re already at that point, after surgery + four chemo infusions. Maybe you’re ready now to make the transition. Cancer-killing treatments make you feel bad, accelerate aging, and damage your body.  In contrast, healing and immune support will feel good in the present and will have beneficial side-effects for other aspects of your health.

   There are many credible alternative cancer treatments out there.  None of them is a universal cure, but all of them have worked for some significant percentage of people who tried them.  The plan will be to choose an alternative clinic or a medication or a diet plan and try it for about 6 weeks. The proposal depends critically on having a sensitive and non-harmful test that you can do every 6 weeks for feedback on whether the treatment is working.

       My proposal will take time.  I believe you have time. You’re not going to die this year or next year, and we have time to try at least a dozen treatments.  We don’t expect the first one or the second to work, but there’s a good chance one of them will. There are many, many stories of people who have banished cancer from their bodies.  You’re the next success story, waiting to be told.

   I propose that you tell your oncologist that you want to find out if the 4 doses of chemo have killed the great majority of the cancer, so that you can now strengthen your own system to handle the last few (chemo-resistant) cells.  Tell her that you are open to returning to chemo in the future should it be necessary, but that for the next phase, you want to try a series of alternative treatments that are non-toxic and have only beneficial side-effects. Each of these has worked for some fraction of patients, and your expectation is that one of them will work for you.  Tell her that you would like to ask her to work with you as an expert diagnostician, using blood tests and subjective state of health to tell when a treatment is not working, so you can move to the next option, and to tell you when a treatment is working, so you can stick with it.

    (I believe PET scans are the most informative test for cancer, but your oncologist will know much more than I.  PET scans are expensive, and I imagine that insurers discourage their overuse. More concerning is that the radiation dose is about 100 times a chest x-ray [ref], so we’ll be counting on your oncologist to come up with a less damaging battery of tests that you can do, perhaps as often as every 6 weeks.)

    We have lots of candidate treatments to try, from the Moss Report, from the Polizzi video or a long list of herbal medicines, from your sources and mine.  There are approaches that involve killing cancer cells with medicines that are much less toxic to your non-cancerous cells, for example, intravenous vitamin C, curcumin, cannabis, dichloracetate, and many others.  A complementary approach strengthens the body’s resistance to cancer, especially the immune system. In the end, it must be your own healthy immune system that protects you from cancer. Reishi and other mushroom extracts, Cimetidine=Tagamet, Nigella sativa (kalonji seed), spirulina, and green tea extract are among many nutracuticals that strengthen the body’s resistance to cancer.  I want to remind you especially of the research of Valter Longo, a USC professor who has worked with fasting and diets that discourage cancer.  There are alternative cancer clinics in Canada and Mexico and around the world that have cured some fraction of the people who have sought their help.  

    Almost all of these interventions have been attacked or dismissed as frauds.  Sometimes this is because they really are frauds, and sometimes it is the medical community circling its wagons to avoid infiltration by researchers outside the mainstream.  Until we look in detail at the accusations and the results, it is difficult to tell the difference, and even then we’re often left guessing. Much of the debunking is based on theory–“there is no credible biochemical mechanism by which xyz can cure cancer.”  I take these pronouncements with a grain of salt, and look only at the empirical results. We don’t understand cancer well enough to dismiss anything on theoretical grounds

    Any one of these options has a low probability of providing deliverance from your cancer, but you have time to try 10 or 20 of them, and there is a very good chance that you will respond to one of them.  You are destined to become the next “miracle cure” cancer anecdote — we just don’t know yet which one you will be.

    I’ve mentioned to you a fallback option, in the unlikely event we should find ourselves two or three years from now with a persistent, active threat of cancer.  The last resort would be to replace your immune system with a bone marrow transplant from your niece (or another related donor, preferably younger).  The upside is that the transplanted immune system absolutely will not tolerate your cancer, and will eliminate it promptly.  The downside is that you expose yourself to “graft-vs-host disease”, in which your immune system also treats healthy cells as “foreign” and attacks them.  This is a potentially fatal complication, and would probably consign you to immune suppressants for the rest of your life.

Im in this with you for as long as it takes.  So are your dear friends and family and the deep community of people who are full of gratitude for the years of love and attention you have offered them.

— Josh

Fisetin—a new senolytic

Senolytic drugs have been the most promising near-term anti-aging therapy since the ground-breaking paper by van Deursen of Mayo Clinic published in 2011.  The body accumulates senescent cells as we age, damaged cells that send out signal molecules that in turn modify our biochemistry in a toxic, pro-inflammatory direction.  Though the number of such cells is small, the damage they do is great. Van Deursen showed that just getting rid of these cells could increase lifespan of mice by ~25%. But he did it with a trick, using genetically engineered mice in which the senescent cells had a built-in self-destruct switch.  

After that, the race was on to find chemical agents that would do the same thing without the genetically engineered self-destruct.  They must selectively kill senescent cells, while leaving all other cells unharmed. It’s a tall order, because even a little residual toxicity to normal cells can be quite damaging.  Before last week, the two best candidates were FOXO4-DRI and a combination of quercetin with dasatinib.

I’ve written in the past (here and here) that senolytic drugs are our best prospect for a near-term lift on the road to anti-aging medicine.  

Last week, a large research group affiliated with the original May Clinic team published findings about fisetin, the latest and greatest candidate for a senolitic pill, another flavenoid, very close in structure to quercetin. 

They grew senescent and normal cells in a test tube, then tested 11 different plant-derived chemicals for power to kill the one while leaving the other unharmed.  The winner was fisetin.

(MEF stands for Mouse Embryonic Fybroblast, the cells that were cultured in the screening experiment.)

Fisetin is especially interesting because it is cheap, easily available, widely-regarded as safe, but not nearly as well studied as quercetin.

They took the winner, fisetin, and subjected it to a series of tests.  They began with in vitro (cell culture) tests and proceeded to in vivo tests with live animals, culminating with an impressive life span assay in mice.

(The runner-up was curcumin, less interesting perhaps only because it has already been extensively studied.  The curcumin molecule is unrelated to quercetin or fisetin, and is not a flavenoid. I can’t help but wonder if they had subjected curcumin to the same thorough testing that they reserved for fisetin, how would curcumin have fared?)



The paper’s principal findings were:

  • Fisetin has lower liver toxicity (at equivalent doses for senolytic benefit) than any of the other senolytics tested so far.
  • Fisetin reduces pro-inflammatory signaling in a short course given to mice and in long-term experiments where fisetin was added to the mouse chow.
  • Fisetin reduces number of senescent fat cells in a short course given to mice.
  • Mice fed fisetin for long periods had much more glutathione than control mice.  (Glutathione is one of very few marker molecules that seems to be wholly beneficial.)
  • Most impressively, mice fed fisetin late in life lived 10-15% longer than control mice. This represents a 50% increase in the remaining lifespan after the intervention.

What we know and what we’d really like to know

We’d like to know, do humans who take large doses of fisetin live longer?  Do they have toxic side-effects? These questions require decades to answer.

Does fisetin reduce age markers in humans, especially methylation age?  This is a feasible study, since the test is mature and safety of fisetin is fairly well established for short courses.  Perhaps this experiment is being considered; I’ve written to the corresponding authors of the most recent study, in case they haven’t already thought of it.  This test would not be definitive because we know that methylation age is not perfectly correlated with biological age; but if positive it would confirm both that fisetin is accomplishing epigenetic rejuvenation and that methylation tests were correctly informing us of this; a negative result would be ambiguous.

Episodic Dosing

It makes sense that senolytics should be taken periodically, not continuously.  A high dose can be toxic to existing senescent cells, and then getting out of the way, it can allow normal cells to recover from any damage.  This sounds like good theory, but different dosing regimens have not been tested experimentally. In fact, the new paper reports positive results from both high episodic dosing and lower everyday dosing.

The Mayo group had previously tested fisetin, and found it effective in killing some kinds of human senescent cells but not others.  In previous tests, fisetin was found to be effective in senescent fat cells (pre-adipocyte, white adipose tissue), and that is where it was primarily tested in the new studies.  

Authors’ comments

They note that the episodic treatment and short half-life suggest that the benefits of fisetin come from its senolytic action, rather than other actions as an antioxidant and signal molecule.  They emphasize that clearing senescent white blood cells and making room for new, active white blood cells are activities that enhance the benefits of fisetin, since white blood cells contribute to clearing the remaining senescent cells.  

Fisetin has previously been shown to have anti-cancer activity and to inhibit inflammatory signals directly.  Here is a review of benefits of fisetin from three years ago.  Drugage lists just two previous lifespan studies with fisetin, with encouraging results from yeast and fruitflies.

The Bottom Line

If we choose to take fisetin at this stage in the science, we are early adopters, and our main concern ought to be safety.  There is little doubt that killing senescent cells will be beneficial. But what is the toxic burden of fisetin, and what dosage can we safely take without risk of damage to normal cells?  The current study covers a lot of ground but doesn’t answer this question, apparently because they are convinced that fisetin is quite safe.

Strawberries, apples, grapes, and onions all contain fisetin, but at low levels compared to a senolytic dose.  For example, the highest food concentration, 160 ppm, is found in strawberries.  A half pound of strawberries yields 36 mg of fisetin.  We’re still guessing at the therapeutic dose, based on mouse studies, and the experimental dosage in human trials is about 1,000 to 1,500 mg (based on this clinical trial), the content to 30-40 pounds of strawberries on each of two consecutive days.

In the best cases, fisetin was shown to reduce senescent cell burden by 50% and up to 75% in cell cultures.  This is a good start, and encourages us to think we can do better by combining fisetin with other agents, or perhaps with fasting.

Also reported today,

Clearing Senescent Cells From The Brain In Mice Preserves Cognition

It sounds impressive, but I’m not impressed.  First, mouse models of Alzheimer’s have been discredited repeatedly.  Mice don’t naturally get AD, so they have to be genetically engineered to do so, and the genetically modified mice don’t share the deep causes of human AD.  Time and again, treatments have been found effective in the mouse model that fail to translate to humans. Second, the treatment used in the study to kill senescent brain cells also relied on another genetic modification, and would not be applicable to humans.  

My guess is that effective senolytic agents for humans will be available within a few years, and that they will decrease risk of all age-related disease, including Alzheimer’s.  But this study does little to advance us toward that goal.

A cure for Alzheimer’s? Yes, a cure for Alzheimer’s!

This is the most important column I’ve ever written.  The message is quite complex–dozens of new health parameters to test for and to optimize, all of them interacting in ways that will require new training for MDs.  The message is also as simple as it can be: There is a cure for Alzheimer’s disease. You can stop reading right here, and buy two copies of Dale Bredesen’s book, one for you and one for your doctor:  The End of Alzheimer’s.

Dr Bredesen’s spectacular success is easily lost in a flood of overly-optimistic, early hype about any number of magic cures.  This is an excuse for the New York Times, the Nobel Prize committee, and the mainstream of medical research, but it’s no excuse for me.  I’ve known Bredesen for 14 years, and I’ve written about his work in the past.  His book has been out for a year, and I should have written this column earlier.

I suspect you’re waiting for the punch line: what is Bredesen’s cure?  That’s exactly what I felt when I read about his work three years ago. But there isn’t a short answer.  That’s part of the frustration, but it’s also a reason that Bredesen’s paradigm may be a template for novel research approaches cancer, heart disease, and aging itself.

The Bredesen protocol consists of a battery of dozens of lab tests, combined with interviews, consideration of life style, home environment, social factors, dentistry, leaky gut, mineral imbalances, hormone imbalances, sleep and more.  This leads to an individual diagnosis: Which of 36 factors known to affect APP cleavage are most important in this particular case? How can they be addressed for this individual patient?

Brain cells have on their surface a protein called APP, which is a dependence receptor.  It is like a self-destruct switch whose default is in the ON position.  The protein that binds to the receptor is a neurotrophin ligand, and in the absence of the neurotrophin ligand,  the receptor signals the cell to die.

APP cleavage is the core process that led Bredesen down a path to his understanding of the etiology of AD 16 years ago.  APP is Amyloid Precursor Protein, and it is sensitive to dozens of kinds of signals, adding up the pros and the cons to make a decision, to go down one of two paths.  It can be cleaved in two, creating signal molecules that cause formation of new synapses and formation of new brain cells; or it can be cleaved in four, creating signal molecules that lead to trimming back of existing synapses, and eventually, to apoptosis, cell suicide of neurons.

In a healthy brain, these two processes are balanced so we can learn new things and we can forget what is unimportant.  But in the Alzheimer’s brain, destruction (synaptoclastic) dominates creation (synaptoblastic), and the brain withers away.

On the right, one of the fragments is beta amyloid.  Beta amyloid blocks the dependence receptor, so the receptor cannot receive the neurotrophin ligand that gives it permission to go on living.  Beta amyloid is one of the 4 pieces, when the APP molecule goes down the branch where it is split in 4.

One of the signals that determines whether APP splits in 2 or in 4 is beta amyloid itself.  This implies a positive feedback loop; beta amyloid leads to even more beta amyloid, and in the Alzhyeimer’s patient, this is a runaway process.  But positive feedback loops work in both directions–a boon to Bredesen’s clinical approach. If the balance in signaling can be tipped from the right to the left pathway in the diagram above, this can lead to self-reinforcing progress in the healing direction.  In the cases where Bredesen’s approach has led to stunning reversals of cognitive loss, this is the underlying mechanism that explains the success.

Amyloid has been identified with AD for decades, and for most of that time the mainstream hypothesis was that beta-amyloid plaques cause the disease.  (Adherents to this view have been referred to jokingly as BAPtists.) But success in dissolving the plaques has not led to restored cognitive function.  In Bredesen’s narrative, generation of large quantities of beta amyloid are a symptom of the body’s attempts to triage a dying brain.


To tip the balance back toward growing new synapses

Having identified the focal point that leads to AD, Bredesen went to work first in the lab, then in the clinic, to identify processes that tend to tip the balance one way or the other.  He has compiled quite a list.

  • Reduce APPβ-cleavage
  • Reduce γ-cleavage
  • Reduce caspase-6 cleavage
  • Reduce caspase-3 cleavage
    (All the above are cleavage in 4)
  • Increase α-cleavage (cleavage in 2)
  • Prevent amyloid-beta oligomerization
  • Increase neprilysin
  • Increase IDE (insulin-degrading enzyme)
  • Increase microglial clearance of Aβ
  • Increase autophagy
  • Increase BDNF (brain-derived neurotropliic factor)
  • Increase NGF (nerve growth factor)
  • Increase netrin-1
  • Increase ADNP (activity-dependent neuroprotective protein)
  • Increase VIP (vasoactive intestinal peptide)
  • Reduce homocysteine
  • Increase PPZA (protein phosphatase 2A) activity
  • Reduce phospho-tau
  • Increase phagocytosis index
  • Increase insulin sensitivity
  • Enhance leptin sensitixity
  • improve axoplasmic transport
  • Enhance mitochondnal function and biogenesis
  • Reduce oxidative damage and optimize ROS (reactive oxygen species) production
  • Enhance cholinergic neurotransmission
  • Increase synaptoblastic signaling
  • Reduce synaptoclastic signaling
  • Improve LTP (long-term potentiation)
  • Optimize estradiol
  • Optimize progesterone
  • Optimize E2:P (estradiol to progesterone) ratio
  • Optimize free T3
  • Optimize free T4
  • Optimize TSH (thyroid-stimulating llormone)
  • Optimize piegnenolone
  • Optimize testosterone
  • Optimize cortisol
  • Optimize DHEA (deliydroepiandrosterone)
  • Optimize insulin secretion and signaling
  • Activate PPAR-γ (peroxisome proliferator-activated receptor gamma)
  • Reduce inflammation
  • Increase resolvins
  • Enhance detoxification
  • Improve vascularization
  • Increase cAMP (cyclic adenosine monophosphate)
  • Increase glutathione
  • Provide synaptic components
  • Optimize all metals
  • Increase GABA (gamma-aminobutyric acid)
  • Increase vitamin D signaling
  • Increase SirT1 (silent information regulator T1)
  • Reduce NF-κB (nuclear factor kappa-ligllt-chain-enhancer of activated B cells)
  • Increase telomere length
  • Reduce glial scarring
  • Enhance stein-cell-mediated brain repair

This explains why no single drug can have much effect on AD; it’s because the primary decision point depends on a balance among so many pro-AD (synaptoclastic) and anti-AD (synaptoblastic) signals.  Addressing them all may be impractical in any given patient, so the Bredesen protocol is built around a detailed diagnostic process that identifies the factors that are most important in each individual case.

Three primary types of AD

Bredesen’s diagnosis begins with classifying each case of AD into one of three broad constellations of symptoms, with associated causes.


Type I is inflammatory. It is found more often in people with carry one or two ApoE4 alleles (a gene long associated with Alzheimer’s) and runs in families. Laboratory testing will often demonstrate an increase in C- reactive protein, in interleukin-2, tumor necrosis factor, insulin resistance and a decrease in the albumin:globulin ratio.

Type II is atrophic. It also occurs more often those who carry one or two copies of Apoε4, but occurs about a decade later. Here we do not see evidence of inflammatory markers (they may be decreased), but rather deficiencies of support for our brain synapses. These include decreased hormonal levels of thyroid, adrenal, testosterone, progesterone and/or estrogen, low levels of vitamin D and elevated homocysteine.

Type III is toxic.  This occurs more often in those who carry the Apoε3 allele rather than Apoε4 so it does not tend to run in families. This type tends to affect more brain areas, which may show neuroinflammation and vascular leaks on a type of MRI called FLAIR, and associated with low zinc levels, high copper, low cortisol, high Reverse T3, elevated levels of mercury or mycotoxins or infections such as Lyme disease with  its associated coinfections.  

(This box quoted from Dr Neil Nathan’s book review)

There’s also a Type 1.5, associated with diabetes and sugar toxicity, a Type IV, which is vascular dementia, and a Type V which is traumatic damage to the brain.
These categories are just a start.  The patient will work closely with an expert physician to determine, first, where are the most important imbalances to address, and, second, which of the changes that cna address them are most accessible for the life style of this particular patient.



Bredesen wrote a paper in 2014 about successes in reversing cognitive decline with his first ten patients.  As of this writing, he has treated over 3,000 patients with the protocol called RECODE (for REversal of COgnitive DEcline), and he claims success with all of them, in the sense of measurable improvement in cognitive performance.  This contrasts with the utter failure of all previous methods, which claim, at best, to slow cognitive decline.

Translation to the millions of Alzheimer’s patients will require training of local practitioners all across the country.  A few doctors have already learned parts of the Bredesen protocol, and Bredesen’s website can help you find someone to guide your program, but you will probably have to travel.  The first training for doctors is being organized now through the Institute for Functional Medicine.



This is a new paradigm for how to study chronic, debilitating diseases.  Type 2 diabetes comes to mind as the next obvious candidate for reversal through an individualized, comprehensive program.  Terry Wahls has pioneered a similar approach with MS.  Cancer and heart disease may be in the future.

I’ll go out on a limb and say I think Bredesen’s protocol is the most credible generalized anti-aging program we have.  (Blame me for the hyperbole, not Dr Bredesen — he has never made any such claim.) Could we adopt Bredesen’s research method to accelerate research in anti-aging medicine?  Perhaps biomarkers for aging (especially methylation age) are approaching a point where they could be used as feedback for an individualized program, but Horvath’s PhenoAge clock will probably have to be 10 times more accurate to be used for individuals.  Averaging over ~100 individuals can give this factor of 10 in a clinical trial.  Still, we don’t have the kind of mechanistic understanding of aging that Bredesen himself developed for AD before bringing his findings to the clinic; and this is probably because causes of aging are more complex and varied than AD.

Disclaimers:  I’m pre-disposed to think highly of Dale Bredesen and his ideas for 3 reasons.  He was a friend to me, and gave me a platform when I was new to the field of aging.  He believes that aging is programmed. And his multi-factorial approach parallels the research I have advocated for researching other aspects of aging.

Rhonda Patrick interviews Dale Bredesen on FoundMyFitness

Aubrey & Me

I’ve been in the field of aging research from the late 1990s, just the time when Aubrey de Grey was getting his start.  Before others, Aubrey had the vision to realize that cancer, heart disease, and Alzheimer’s would never be conquered without addressing their biggest risk factor: aging.

From the beginning, I admired Aubrey’s successes in communicating with scholars and the public, and I reached out to him.  He has always been gracious and supportive of me personally, appreciating the large common ground that we share. There is, however, one foundational issue on which we disagreed from the start.

Aubrey regards aging as an accumulation of damage.  Evolution has permitted the damage to accumulate at late ages because (as Medawar theorized in 1952) there is little or no selection against it, since almost no animals live long enough in the wild to die of old age.  Aubrey’s program is called SENS, where the E stands for “engineering.”   The idea is to engineer fixes to the 7 major areas where things fall apart with age.

I regard aging as a programmed process, rooted in gene expression.  Just as we express growth genes when we are in the womb and ramp up the sex hormones when we reach puberty, so the process continues to a phase of self-destruction.  In later life, we over-express genes for inflammation and cell suicide; we under-express genes for antioxidants, autophagy (recycling), and repair of biomolecules.  I believe in an approach to anti-aging that works through the body’s signaling environment.  If we can shift the molecular signals in an old person to look like the profile of a young person, then the person will become young.  The body is perfectly capable of doing its own repair, and needs no engineering from us.

Over the years, research findings have accumulated, and both Aubrey and I have learned a thing or two.  I’m happy to say that our favored strategies are converging, even as our philosophical underpinnings continue to differ.

A unifying idea in my research has been that aging is an evolved adaptation.  This is a statement about evolutionary biology, but I came to it before I studied evolution, by looking at the phenomenology and genetics of aging.

  • The body does not appear to be doing its best to stay young.  We can see this because when the body is under stress, it has less available resources, but manages to a better job of protecting us from aging damage.  This phenomenon is called hormesis.
  • There are single genes that can be disabled, greatly extending lifespan in worms. Some of these have no known detrimental side-effects (pleiotropy).  These could only have persisted in the genome if natural selection is favoring aging for its own sake.  Similar genes exist in higher organisms, though their effects on lifespan are not as dramatic as the 10-fold increase in worms’ life expectancy in worms that comes from eliminating both copies of AGE-1.
  • Most genes that affect the rate of aging have been around for a long time, and do the same job.  This means they are evolutionarily conserved. For example, insulin is the most effective modulator of aging in mammals (including humans).  In higher animals, insulin is secreted by the pancreas, from whence it regulates blood sugar and fat storage. But yeast cells existed half a billion years before the first mammals, and have no pancreas, as my friend Barja has pointed out; and yet insulin was already a primary modulator of aging in yeast.Article Image

Programmed aging and optimism

There was a time when I spoke of “aging genes” and looked for drugs that could jam their targets and turn the genes off.  Meanwhile, the science of epigenetics, or gene expression, was coming of age, so to speak. We learned that genes are turned on and off, not just in different tissues, but at different times of life.  I came to think less in terms of “aging genes”, more about multipurpose genes that are deployed in appropriate combinations when we are young, keeping us strong and healthy. But as we get older, the proportions change.  Aging is not accomplished via new mechanisms of self-destruction, which evolution invented for that purpose. Rather, the proportions are re-shuffled and change gradually, with effects that are more and more detrimental over time.

  • For example, the immune system is vital for protecting the body, but it becomes indiscriminate with age. In older people, the immune system fails to protect us from microbial infections, and simultaneously, immunity turns against the self.  Autoimmunity contributes to arthritis and to Type 2 Diabetes (metabolic syndrome), as well as playing a role in AD.
  • For example, p53 is a gene that promotes apoptosis, or cell suicide.  We need for cells to be smart enough to destroy themselves when they are infected with a virus or if they are cancerous.  But later in life, apoptosis is on a hair trigger, and we lose muscle and nerve cells that are still healthy and functional.
  • For example, inflammation is used as a primary defense against microbes, and a way to eliminate tissue around a wound so that it can be replaced; but as we get older, signals that promote inflammation are dialed up higher and higher.  Chronic inflammation contributes importantly to all the diseases of old age.

Twenty years ago, I imagined one or a few medications that would block the effects of aging genes.  I wrote that the thesis of programmed aging implied great optimism about the ease with which aging might be combatted.  I thought that merely lengthening telomeres might add many years to our lifespan.

Ten years ago, I saw that what was needed was re-balancing of signaling molecules to create a more youthful environment.  My hope was that a few transcription factors (master regulator genes) might control a large number of signal molecules and we might set the clock by controlling just a handful of master signals.

More recently, I have come to realize that shortening telomeres are only a small part of the aging program.  Worse, there is no clear line between transcription factors and hormones. Most hormones affect transcription, and most transcription factors have direct metabolic effects.  There are thousands of transcription factors in the human genome.  As a result, my robust optimism has been tempered, and I have come to think that we need to look for ways to re-balance a great number of genes to effect rejuvenation.  I still believe in a signaling approach, but I see signals as a tangled web of cause and effect, in which every cause is also an effect, and every effect has a side-effect.  Modulation of the signaling system toward a more youthful state is possible, but not easy.

Aubrey’s program, too, has changed over time

Aubrey has never believed that aging evolved as a program, but rather that aging is a manifestation of damage that is permitted to accumulate because of evolutionary neglect.  Recently, he has argued explicitly against the idea of programmed aging, not for the reasons that traditional evolutionists offer, but by an argument that is uniquely his own.  In his words, “it is impossible for a species to maintain two sets of genetic pathways whose selected actions diametrically oppose each other. Specifically, since we clearly have a great deal of anti-aging machinery…we cannot also have pro-aging machinery.”  (My response is that we have pro-aging and anti-aging machinery that are activated at different times of life.–see Aubrey’s comment below.)

Over two decades, Aubrey, too has paid attention to research results, and his thinking about what is necessary to achieve rejuvenation is changing.  I see changes in the combinations of signal molecules and call it an evolved program. Aubrey sees the same thing and calls it “dysregulation”, which is a kind of damage.  Aubrey and I agree that re-balancing of hormones and other signal molecules is going to be essential.

Aubrey now finds optimism in the existence of what he calls “cross-talk”.  If we engineer a fix for one kind of damage, the body may sometimes regain the ability to repair other, seemingly unrelated kinds of damage.  Hence, we may not have to engineer solutions to everything—some will come for free. A dramatic example is in the benefit of senolytics. Cells become senescent over time.  I see this as a programmed consequence of short telomeres; Aubrey sees it as a response to damage in the cells. But both of us were surprised and delighted to learn, a few years ago, that elimination of senescent cells in mice had 20-30% benefits for lifespan.  Even though only a tiny fraction of all cells become senescent, they are a major source of cytokines (signal molecules) that promote inflammation and can cause nearby cells to become senescent in a vicious circle; this apparently accounts for the great benefit that comes from eliminating them.  If we find appropriately selective senolytic agents that can eliminate senescent cells without collateral damage, then the signals that up-regulate inflammation will be cut way back, and a great deal of the work needed to repair inflammatory damage is obviated.

The SENS 7

The SENS web site still lists the same 7 categories of damage that Aubrey has used for many years.  But the program to address these 7 has shifted a bit from bioengineering of exogenous solutions to signaling approaches that support the body’s innate mechanisms (which we know are sufficient to keep the body in good repair through several decades of early life).  For eliminating the plaques associated with AD, SENS at one time favored the engineering of artificial antibodies that would attack them, but more recently they see promise in the discovery of Dr. Sudhir Paul that our bodies already have catalytic antibodies, each capable of destroying many antibodies and re-cycling itself for the next one.  Where once Aubrey saw the need for tissue engineering to replace worn-out body parts, he now sees promise in reprogramming somatic cells to become stem cells, so that our bodies can regenerate damaged tissues endogenously.  Aubrey’s 1999 dissertation in biochemistry was about the theory that aging was caused by the damage inflicted by free radicals generated in our mitochondria, but he has long since embraced the fact that free radicals have an important role as signal molecules, so that anti-oxidants are not helpful for anti-aging.

Dr Aubrey de Grey presents a Director's Colloquium to the NASA Ames Research Center staff entitled 'Prospects for defeating aging altogether' Dr. de Grey is a British bomedical gerontologist educated at Cambridge University in the UK. A video of the presentation is currently available at the NASA Ames Library.

Aging is not the only threat to human life

One respect in which my thinking has always departed from Aubrey’s is that I see humans as part of a continuous web of life on earth, integrated into a global ecosystem.  Aubrey doesn’t worry about the Sixth Extinction that human activity has initiated because he anticipates that future humans will invent ways to support future human life as necessary.  I value nature for its own sake, and I also believe that human life depends on ecoystem support in ways for which we have seen hints, but that we have not yet begun to study. Aubrey draws a sharp line between the value of human life and the value of other life, and he is highly optimistic about the ability of our species to find new ways to sustain ourselves in a post-ecologic world.


The Bottom Line

In my youthful enthusiasm, I was entirely too optimistic about the prospects for near-term anti-aging fixes.  Aubrey was probably too conservative about the scope of what needed to be done to generate man-made solutions for problems the body can’t solve itself.  I have come to understand the complexity of the body’s signaling network, and the fact that it is inseparable from cellular metabolism. Aubrey has come to realize that the body has endogenous solutions that can be activated more easily than we can engineer substitutes for them.  I’ve been moving the timeline out, as he has been moving the timeline in, and there is much that we agree about.

I’m grateful to Aubrey — we all are — for the energy, the expertise, and the humor that he has brought to his chosen role, as a public advocate for bringing anti-aging strategies into the mainstream of medical research.


Chinese Longevity Herb

Fo-ti is a root herb from traditional Chinese medicine that has been used for centuries as an anti-aging tonic, and has shown promise in limited Western-style analyses.  Interest has been held back by reports of liver toxicity, but there is some indication that the benefits can be separated from the toxic effects. In my readings, I found anecdotal evidence for rejuvenation plus one older study of impressive life extension in quails. I also found many more recent studies documenting beneficial biochemical effects which may be counted indirect evidence that makes life extension more credible.  There were two clinical trials, both with promising results.

I’ve been looking into the effects of a root herb called Fo-ti or He shou wu (何首乌) or Polygonum multiflorum Thunbergia, since a friend emailed me about rejuvenating effects when he fed it to his ancient German shepherd.  I’ll call it PMT for the remainder of this page. I’ve consulted the usual PubMed sources, in addition to books on Traditional Chinese Medicine (TCM), and some scientific articles in Chinese, which I ran through Google Translate, with fair results.  

TCM is based on herbal combinations and formulas.  Each ingredient has many active compounds, and the art of TCM is to combine the combinations.  Western medicine likes to study one compound at a time, based on a scientific tradition (reductionism) that tries to understand each separate piece, then study interactions from that understanding as a foundation.  The reductionist approach was responsible for the explosive success of 19th Century physics, and has been popular ever since, but it is not obviously the best way to make progress in 21st Century biology [Carl Woese philosophy piece].  Another reason for the Western preference for single-compound treatments comes from patent law, which encourages the testing of purified compounds and disallows patents for whole plants. But our bodies are complex, homeostatic systems, and it is rarely true that the combined effect of two drugs is just the sum of the effects of each separately.  Strong interactions are the rule, rather than the exception. I believe that we are not going to find a single Fountain of Youth molecule, so I have been an advocate for high-throughput screening of many combinations of treatments, looking for combinations that stand out as especially effective. If we continue to study purified molecules in isolation, it may be a long time before we get to the point where we understand the biochemistry well enough to identify magic combinations on theoretical grounds.

A curious side-note: It is reasonable to expect some combinations of biochemicals to synergize in the human body.  But why should we expect these combinations to be found regularly in a single plant?  Herbal medicines are unreasonably effective in this regard.

Here [1988] is the one lifespan trial that I was able to find, which reports 50% life extension in Japanese quails.  I looked on Cochrane and, and found nothing. However, Joe Cohen over at Self-Hacked has an extensive article. “More than 100 chemical compounds have been isolated from Fo-ti, and the most biologically relevant components have been determined to be from the families of stilbenes, quinones, flavonoids, and phospholipids…Fo-ti exhibits a wide spectrum of pharmacological effects, including anti-aging, immunologic, neuroprotective, anticancer and anti-inflammatory effects.”  Stilbenes are molecules in the resveratrol family; quinones are like CoQ10, and flavonoids are polycyclic molecules in the quercetin family.

Most of the rest of what I report here comes from this Chinese review [王伽伯, 2016] and this English language review [Bounda & Feng, 2015].

Laboratory studies and clinical practice have demonstrated that PMT possesses various biological and therapeutic actions, including anti-tumor,[16,17] antibacterial,[18] anti-inflammatory,[13] anti-oxidant,[19,20,21] anti-HIV,[22] liver protection,[23,24] nephroprotection,[25] antidiabetic,[15,26] anti-alopecia,[27,28] and anti-atherosclerotic activities.[29,30] It has been also reported to exert preventive activity against neurodegenerative diseases,[31,32,33,34,35] cardiovascular diseases and to reduce hyperlipidemia as well.[36,37] — Bounda & Feng

Anti-inflammatory: [13] is a Korean study that found inhibition of inflammatory cytokines in white blood cells of mice.  Other studies [77] show suppression of NFκB.

Liver protection: [23] A Taiwanese study that demonstrated reduced toxicity from CCl4 after mice were treated with PMT extract.  [24] PMT reversed liver cirrhosis in mice.

Antidiabetic: [15] inhibits enzymes that digest starch [26] is an impressive study, that demonstrates inhibition of TGF-β1 and COX-2, and simultaneous enhancement of SOD and glutathione from a chemical extract of PMT called 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (TSG).  TSG is chemically similar to resveratrol, and in a worm study was more effective than resveratrol at increasing lifespan (22%).

Anti-atherosclerotic: [29] Mice don’t get heart disease so they work with rabbits.  Large reductions in measures of arterial blockage in rabbits fed a water-extract of PMT.  [30] This is really about anti-inflammatory benefits of TSG fed to mice and rats.

Neurodegeneration: [31] This was about adaptogenic benefit in mice.  Mice were protected from nerve damage by paraquat if they had been prepared with extract of PMT.  [32] worked with a mice that had been genetically modified to give them Alzheimer’s disease.  TSG was found to ameliorate the loss of memory. [33] Older rats lose their memory, as tested in their ability to remember from day to day the location of a hidden platform in a tank of water.  TSG protected memory in older rats. [34] This is a study for people who believe in the Amyloid-β theory of Alzheimer’s disease.  A large number of herbal substances were screened in cell lines that generate Amyloid-β, and the only effective inhibitor was found to be PMT extract. [9] Suppresses lipid peroxidation in response to Amyloid-β in a mouse model and increases glutathione. [116] Another successful trial, this time of TSG in a mouse model of AD. [119, 120 is in Chinese] Two clinical studies found substantial improvement in cognitive performance of AD patients with PMT.

Liver injury from PMT is linked to a certain genetic difference, labeled CYP1A2 * 1C.  I didn’t find anything more about this genetic variant. Curiously, I found several studies that claimed that PMT protects the liver, for example this.

My inclination is to look for empirical evidence and downplay theory (both Western and Chinese theory).  I believe that the emphasis on single compounds is a serious limitation of Western medical research, because the interactions are more important than the individual effects.  For me, it is an attractive feature of TCM that there is so much accumulated wisdom, not just about herbs that contain many active ingredients, but about potions that combine typically a dozen or so herbs that have been found to work well together.  So the maddening thing I’ve found is that the Chinese scientists who have studied PMT and other promising Chinese herbs fall into the Western trap and isolate one compound at a time to study their effects. What is missing is the lifespan studies based on whole herbs, or combinations of herbs, as they would be prescribed by a traditional Chinese herbalist.

I went to a local herbalist this week and asked for advice about He Shou Wu.  She explained to me that in TCM, herbs are always given in combinations. There are classic formulas with 6 or 10 or 20 herbs, and these are adjusted for individual prescription.  The main ingredients are large quantities of the herbs that move the metabolism in some direction, and the lesser ingredients counterbalance the main ingredients by pushing in the opposite direction.  Some of the directions they talk about correspond to observables we might recognize (high or low energy, sexual stimulant), and some of them are more esoteric (wet or dry, hot or cold, yin or yang). She gave me a formula with He Shou Wu as the main ingredient, and I’m going to do some more reading before I decide whether to take it.

In the meantime, I’m taking a gram of He Shou Wu extract processed with black beans each morning before breakfast and I think I detect an increase in aerobic stamina which has not listed anywhere as one of the benefits.

Acknowledgement: The idea for this research came from Jeff Bowles, who is a frequent commenter on this blog.  The Chinese research was kindly supplied by Wen-jun Li, a post-doc in the Beijing lab where I have worked the last 3 summers.

If you’re over 50, don’t stop taking aspirin

This week, a headline-making study in the New England Journal of Medicine sought to cast doubts on long-established science that says daily aspirin can be a broadly-effective anti-aging tonic.  I’m writing this response because I think that this new, small study has to be viewed in the context of many larger studies over many decades that together make a solid case for aspirin’s benefits.  

Aspirin has two kinds of effects: First, aspirin thins the blood, reduce clotting, which lowers the risk of most kinds of heart attacks and stroke (ischemic) while raising the risk of bleeding ulcers and  hemorrhagic stroke.  Second, aspirin lowers the level of systemic inflammation, which reduces risk of heart disease, stroke, most cancers, and Alzheimer’s disease.

Historically, daily low-dose aspirin began to be prescribed broadly to middle-aged and older adults in the 1960s as the medical establishment theorized about the first effect.  This led to a grand natural experiment—tens of millions of older people taking low-dose aspirin. Studies comparing these people with matched populations who didn’t take aspirin have shown lower rates of all-cause mortality, Alzheimer’s dementia, and of cancer and probably of heart disease as well.  These studies are based on millions of tabulated deaths. The current study is based on 1052 total deaths in the aspirin group and the placebo group, and the difference between the two was barely statistically significant in the direction against aspirin.

Summary of past studies

Eidelman, JAMA, 2003: Summarizing 5 trials, they found aspirin was associated with a 32% reduction in the incidence of first heart attacks.  Statistical significance was 2 chances in 100,000 (p<0.00002).

Methods  A computerized search of the English literature from 1988 to the present revealed 5 published trials: the Physicians’ Health Study (22,071 participants), the British Doctors’ Trial (5,139), the Thrombosis Prevention Trial (5,085), the Hypertension Optimal Treatment Study (18,790), and the Primary Prevention Project (4,495).

Results  Among the 55,580 randomized participants (11,466 women), aspirin was associated with a statistically significant 32% reduction in the risk of a first MI and a significant 15% reduction in the risk of all important vascular events, but had no significant effects on nonfatal stroke or vascular death.

Conclusions  The current totality of evidence provides strong support for the initial finding from the Physicians’ Health Study that aspirin reduces the risk of a first MI. For apparently healthy individuals whose 10-year risk of a first coronary event is 10% or greater, according to the US Preventive Services Task Force and the American Heart Association, the benefits of long-term aspirin therapy are likely to outweigh any risks.

Rothwell, The Lancet 2011: Summarizing 8 trials, they found aspirin was associated with a 21% reduction in the incidence of all cancers.  Statistical significance was 1 chances in 10,000 (p<0.0001).

In eight eligible trials (25,570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0·79, 95% CI 0·68–0·92, p=0·003). On analysis of individual patient data, which were available from seven trials (23,535 patients, 657 cancer deaths), benefit was apparent only after 5 years’ follow-up (all cancers, hazard ratio [HR] 0·66, 0·50–0·87; gastrointestinal cancers, 0·46, 0·27–0·77; both p=0·003). The 20-year risk of cancer death (1634 deaths in 12 659 patients in three trials) remained lower in the aspirin groups than in the control groups (all solid cancers, HR 0·80, 0·72–0·88, p<0·0001; gastrointestinal cancers, 0·65, 0·54–0·78, p<0·0001), and benefit increased (interaction p=0·01) with scheduled duration of trial treatment (≥7·5 years: all solid cancers, 0·69, 0·54–0·88, p=0·003; gastrointestinal cancers, 0·41, 0·26–0·66, p=0·0001). The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer. For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0·66, 0·56–0·77, p<0·0001). Benefit was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age—the absolute reduction in 20-year risk of cancer death reaching 7·08% (2·42–11·74) at age 65 years and older.

Wang, Journal of Alzheimer’s 2015: Summarizing 11 trials, they found aspirin was associated with a 49% reduction in the incidence of dementia.  Statistical significance was less than 1 chances in a billion (p<0.0000000005).

Objective: Alzheimer’s disease, the most prevalent dementia, is a prominent source of chronic illness in the elderly. Laboratory evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) might prevent the onset of Alzheimer’s disease. Since the early 1990s, numerous observational epidemiological studies have also investigated this possibility. The purpose of this meta-analysis is to summarize and evaluate available evidence regarding exposure to nonaspirin NSAIDs and risk of Alzheimer’s disease using meta-analyses of published studies. Methods: A systematic search was conducted using Medline, Biological Abstracts, and the Cochrane Library for publications from 1960 onwards. All cross-sectional, retrospective, or prospective observational studies of Alzheimer’s disease in relation to NSAID exposure were included in the analysis. At least 2 of 4 independent reviewers characterized each study by source of data and design, including method of classifying exposure and outcome, and evaluated the studies for eligibility. Discrepancies were resolved by consensus of all 4 reviewers. Results: Of 38 publications, 11 met the qualitative criteria for inclusion in the meta-analysis. For the 3 case-control and 4 cross-sectional studies, the combined risk estimate for development of Alzheimer’s disease was 0.51 (95% CI = 0.40–0.66) for NSAID exposure. In the prospective studies, the estimate was 0.74 (95% CI = 0.62–0.89) for the 4 studies reporting lifetime NSAID exposure and it was 0.42 (95% CI = 0.26–0.66) for the 3 studies reporting a duration of use of 2 or more years. Conclusions: Based on analysis of prospective and nonprospective studies, NSAID exposure was associated with decreased risk of Alzheimer’s disease. An issue that requires further exploration in future trials or observational studies is the temporal relationship between NSAID exposure and protection against Alzheimer’s disease.


Problems with the present study

Because of small numbers and short duration, the result of the study was only marginally significant (p<0.05).  The aspirin group had higher cancer rates and lower heart attack rates than placebo.

Typically, doctors advise patients to start low-dose aspirin around age 50, but this study was with patients more than 70 years old who had no cardiovascular symptoms by age 70.  Most people by age 70 have had some cardiovascular diagnosis before age 70, so this is an unrepresentative sample. The study fails to address the question, how many deaths and how many diseases could be avoided between the ages of 50 and 70?  This is the period in life when inflammation is most active, and a great deal of destruction of the body’s veins, joints, and nervous system happens during these years. Excluding those with a history of heart disease during those ages is excluding just the people most likely to be helped by aspirin.  Of course, when you’re 50 and considering whether to start on aspirin, you may not know whether you’re lucky enough (or have the right genes) to be in the group that will do fine for the next 20 years without it.

This table breaks the composite test group into sub-groups according to various criteria.  Dots to the right of the line mean “aspirin was worse”, and to the left mean “aspirin was better”.  Among the subgroup in the US, aspirin was better. Among people who had never taken aspirin before, aspirin was better.  Among people within fairly wide limits of a “normal” weight range, aspirin was better.

Why are we seeing this?

Scientists are only human, and their environment, their preconceptions, and their incentives shape the way that statistics are handled.  In my experience, it is not difficult to make a small effect look like a (p<0.05) effect by making consistent choices in the way the data are treated, none of which are suspect or dishonest.  If the group had come up with the conventional and accepted conclusion based on such a small study, there would have been no prominent publication, no headlines, probably no follow-on grant. So they had every incentive to perform the analysis in a way that makes the results appear more interesting than they are.

Heat shock / Cold shock

Heat Shock Protein

[My sources for much of this article are a 2018 review from University of Campinas, Brazil and a 2016 review on hormesis by Joan Smith Sonneborn, as well as the ever-inspiring and accessible summaries by Rhonda Patrick.]

Most animals have the latent ability to live longer when stressed.  It’s called hormesis, and it’s a major clue concerning the nature and evolutionary provenance of aging.  The body compensates when stressed—that’s no surprise—but the remarkable thing is that it overcompensates so that, paradoxically, stress ends up by lengthening lifespan. Sometimes.

One of the prime responses to stress at the cellular level is Heat Shock Proteins, discovered in 1962 in fruit flies.  Heat was the stressor that led to the original discovery of HSP, and the word “heat” remained with the name, though it soon became clear that HSP are secreted in response to many kinds of stress, including cold.  HSP are not a single protein, but a family of molecules, all of which are highly conserved; the human versions are remarkably similar to HSP in flies and even yeast cells.

HSP protects delicate biomolecules from damage.  HSP act as chaperones, helping newly-created proteins to fold properly, and helping misfolded proteins to find their correct shape.  HSP protect against sarcopenia (muscle-wasting) which is responsible for so much frailty. Lab worms with an extra copy of an HSP gene live longer.   Here is a closely-related finding for fruitflies, but there are contradictory findings for mice [pro, con].

Heat Shock Factor (HSF) is a signal molecule that turns on the full set of HSP genes.  It turns on a great many other protective proteins at the same time, a whole library, in fact, of protections.   Calorie restriction and exercise both activate HSP, but protein restriction may attenuate HSP.  HSP induction in response to HSF declines with age in rodents, but not if they are calorically restricted. Pro-biotics and high-fiber diets encourage microbiome signaling that increase HSP expression, at least in mice.  Insulin resistance, characteristic of type 2 diabetes, suppresses HSP in response to HSF.  High fat diets reduce HSP. Garlic in the diet increases HSP.

HSP is neuroprotective when there is potential damage from a stroke or head injury.  Does HSP protect nerves from the slow damage of aging as well?



In my reading this week, I’ve come to think that saunas may be the second most powerful form of human hormesis after calorie restriction.  Statistics for saunas suppressing cardiovascular disease and especially dementia make you stand up and take notice. Here’s a clear and straightforward article by Rhonda Patrick (FoundMyFitness) about the benefits of saunas.

If you’ve ever run long distances or exercised for endurance, it’s intuitive that increased body temperature will eventually induce strain, attenuate your endurance performance, and accelerating exhaustion. What might not be as intuitive is this: acclimating yourself to heat independent of aerobic physical activity through sauna use induces adaptations that reduce the later strain of your primary aerobic activity. Hyperthermic conditioning improves your performance during endurance training activities by causing adaptations, such as improved cardiovascular and thermoregulatory mechanisms.

I don’t enjoy getting overheated any more than you do, but hey—stress is stressful.  How surprised can we be that heat is a powerful inducer of Heat Shock Protein? Perhaps more interesting is that saunas are associated with increased growth hormone, a far safer and cheaper way to achieve higher HGH levels than injections.  The combination of HGH and HSP help to maintain muscle mass against the erosion that almost always comes with age. Patrick documents that saunas contribute to maintaining (or restoring) insulin sensitivity, and to growth of new brain cells.  Another pathway by which saunas work their magic is norepinephrine=noradrenaline, which is both a neurotransmitter and a hormone, and higher levels are associated with good attention and cognitive performance.

“The greater the discomfort experienced during your workout or sauna, the better the endorphin high will be afterward.”

Jari Laukkanen, a Finnish cardiologist, followed middle-aged sauna-bathers (men) and matched controls for 20 years.  His study found dramatic decreases in cardiovascular deaths, and a 40% drop in all-cause mortality for those reporting sauna use at least 4 times per week for 20 minutes.  A prospective study–planned in advance to follow 2,300 men over 20 years–is the gold standard for epideiology. A 40% drop in mortality is worth about 3 years of extended life.  An even more impressive number: the Alzheimer’s risk of men taking at least 4 saunas a week was only ⅓ as great as those who took 1 sauna a week.  The benefit compared to no saunas at all is likely to be substantially greater yet.

Just this week, there is a new review by Laukkanen, author of the above study, who also did much of the the original research in his review.

The review doesn’t mention cancer, and there have been mixed reports whether saunas and HSP in particular protect against cancer or add to cancer risk.  On the one hand, localized applicatation of heat and even whole body heat are a well-established cancer treatment over 40 years. On the other hand, HSP increases the ability of cells to survive stress, and that includes cancer cells.  There is some evidence that saunas enhance the immune system and that would likely contribute to cancer resistance.  In my judgment, the balance of the evidence is that saunas lower cancer risk.


Choose your poison.

The body responds to alcohol as a poison, and raises levels of HSP.  This may be the mechanism by which alcohol consumption (~1 drink per day) lowers heart attack risk, though cancer risk is increased even at low doses.

I’ve made my choice, and I’ve been a teatotaler my whole life.  It’s been for personal reasons that I never have written about the established epidemiology of alcohol.  Moderate alcohol consumption has conventionally been associated with a modest increase in life expectancy, (~1 year or less), but conventional wisdom could be wrong.  It’s always difficult to separate variables in large population studies, and alcohol consumption is linked to so many different factors, all of them more powerful influences than alcohol itself.



HSP is a stress adaptation, not specialized to heat, and in fact cold temperature can also trigger release of HSP.  That said, cold and heat are not symmetric. Saunas work by raising the core temperature of the body several degrees, as in a fever.  Cold is applied on the skin, and the core of the body works harder to keep its temperature close to normal. The benefit is mediated by the cold-sensing nerves in the skin, which trigger release of norepinephrine, similar to heat exposure.  A specific response to cold is a protein called RMB3, which promotes neurogenesis.

It’s tempting to take your cold shower or plunge into an icy stream after you’ve been working out and your core temperature is elevated.  But this may actually cause delayed cramping and lessen the benefit of your workout.  I hate to say it, but after resistance training is the most beneficial time to take your sauna (if the least comfortable).  If you can’t bear the thought of jumping into a cold shower when your body is already cold, you might try a hot shower first.  Here’s a study that demonstrates a drop in infectious disease rates from hot showers followed by cold.  Hof recommends that you take your cold plunge after a course of deep breathing.

One of the most consistent and profound physiological responses to cold exposure is a robust release of norepinephrine into the bloodstream, as well as in the locus coeruleus region of the brain. — Rhonda Patrick

Does the Wim Hof method increase life expectancy

In the last several years, Dutch extreme athlete Wim Hof has popularized a training discipline that combines breathing exercises, cold immersion, yoga and meditation.

Wim Hof is able to suppress immune response to a standard challenge, suggesting he is also able to consciously suppress the auto-immune response that contributes to arthritis, and probably diabetes and AD as well.  When Hof was studied with metabolic and neurologic sensors, the result indicated that he has acquired conscious control over physiological adaptations which, in the rest of us, are entirely automatic.  Is it possible to learn to dial down inflammation by an act of will, or to control our epigenetic age directly from the mind?  This is an approach to health and perhaps to anti-aging that has always fascinated me, though there is little in the mainstream literature on the subject because it is presumed impossible.  There have long been stories about yogis and ascetic devotees of Eastern religions who culture extraordinary control over their bodies and live to extraordinary ages. Of course, we would like to see these claims subjected to controlled conditions and standardized lab tests, but there are probably good reasons why most ascetic hermits have no interest in taking leave from their mountain caves to serve as lab rats.

There is no direct evidence that Wim Hof training affects aging.  Indirect evidence is that it lowers inflammation, which makes a large contribution to all the diseases of old age, and that it releases norepinephrine and RMB3, both of which are neuroprotective  I’m eager to see if Wim Hof method has an effect on methylation age, and will include it in the Data BETA study that is ramping up this fall (DataBETA is the name I’ve chosen for the Mother of All Clinical Trials.  It stands for Database for Epigenetic Evaluation of Treatments for Aging.)


The Bottom Line

If the Finnish review is to be believed, then hyperthermia—overheating—is one of the most powerful modes of hormesis we know of, ranking second only to calorie restriction.  Just as interesting is the fact that hyperthermia works by a path independent of insulin, so we might hope that there is synergy between saunas (or Bikram yoga) and from calorie restriction (or fasting).  In other words, combining low calorie with high heat might, if we’re lucky, yield life extension equivalent to the sum of the two measures separately.  Cold exposure and the full Wim Hof program, including meditation techniques, show promise, but are further from validation as a life-extending practice.

The Most Effective Personal Anti-aging Program

What are the most effective things you can do to slow the aging process and extend your life expectancy?  This is the question being asked by a clinical trial that I am organizing, and which seems to be rapidly taking shape.  But before the study begins, we have to have candidates to evaluate. We should begin with hypotheses about what we are evaluating.  My idea is to consult some experienced experts, and also to crowd-source this choice, and to ask for your help in selecting the supplements and life habits to be evaluated.

Details of the trial were described in two blog posts last spring [One, Two] and a more technical manuscript submitted in May.  Outcome will be evaluated based on a variant of DNA PhenoAge, taken from a blood test before, amid, and after the two-year trial.  We use methylation pattern differences rather than mortality or health outcomes because the latter take a long time to reveal themselves, and make anti-aging trials prohibitively expensive.  Using methylation clocks as an endpoint is a new idea, and we don’t know if it will work, but if it does, it will be 100 times cheaper and 10 times faster than previous methods. We will have enough bandwidth to test a dozen different measures at once, which itself is a revolutionary step.  

Many measures are known that are thought to increase life expectancy by a year or a few years each.  Of course, we want to know which ones offer their greatest benefits. But even more important, we want to know how they interact, synergize, and interfere with one another.  If any one of these measures offered major benefits—say 20 years of life—its effects would be so apparent that we would probably know it already. Likewise, if these measures added up to 20 years of extra life, we would all know some people who are obviously younger than their chronological age.  Realistically, we must assume that most of the things we do are redundant. Combining metformin with berberine and gynostemma may offer little additional life expectancy compared to any one separately.  A panoply of different anti-inflammatory strategies may be little improvement over an aspirin a day.

But we hope there are exceptions.  If two different measures act via completely different metabolic pathways, we have reason to hope that their effects should compound.  For example, perhaps life extension interventions based on mitochondrial health synergize with interventions based on rebooting the immune system.  Then we might hope that the life extension available from these two measures together is greater than the sum of what we get from the two separately.


Study design

We will not tell the people who sign up for this study what to eat, what pills to take, or how much to exercise.  We will ask people what they are doing, what they are eating, and what supplements they are taking in a detailed questionnaire.  We will select subjects so as to represent a broad array of different strategies and different combinations among these strategies.

Broad, but not too broad.  We will have enough statistical power to estimate the interactions among every pair of measures out of 12 that we take as our independent variables.  These 12 should be chosen in advance, so the study has a clear focus. If there are more than 12, the number of interactions increases rapidly beyond what we can hope to distinguish (with multivariate statistics).  I’ve decided to start with 15, and winnow the list as people sign up for the study and we see what

Here are the criteria I propose:

  • Each measure, separately, should have either human mortality data or longevity data to back it up.
  • The measures should be easily available to all (excluding intravenous drugs or transfusions)
  • The measures should be well-enough known that they are already in common use (and we will have no trouble identifying a diverse group of subjects who use them)

I find that it’s hard to limit the list to 15.  It may make sense to include a few measures that are so well established that every participant will be required to comply in order to be included in the study.  In this category, we might put

  • Non-smoking
  • Limited alcohol consumption (or none)
  • Vitamin D at least 5,000 IU daily
  • Multi-mineral supplement with magnesium, zinc, chromium, and selenium
  • Exercise equivalent to minimum 5 hours a week of walking or yoga

Body weight (BMI) is an important longevity factor, but difficult to account.  Studies show that maximum lifespan is associated with BMI between 21 and 25, but in my interpretation, lower BMI is always beneficial for any given individual.  

BMI Mortality versus age

The reason for the apparent paradox is that individuals have genetic disposition to be overweight or underweight.  Those who are genetically underweight tend to overeat, because they can do so with no social stigma. Those who are genetically overweight feel compelled to diet all the time (women more than men), and they may be restricting calories just to keep their BMI at 25.  These dieters get the most benefit from Caloric Restriction, despite the fact that they don’t look thin.

List of things that lengthen your life

  1. Love.  Men who are married or in close relationships have 7% lower mortality than singles.  The number is 4% for women [ref].  These numbers correspond to less than a year of life expectancy.  A different study finds loneliness increases mortality by 50%, corresponding to almost 5 years of life.
  2. Empowerment: Staying employed is worth up to 14 years, and I like to think this is more about being needed than making money.  This study claims that the big difference is wealth.
  3. Anti-inflammatories: Aspirin, ibuprofen, curcumin, or fish oil.  This study attributes about a year of life expectancy to daily aspirin.
  4. High fiber, a proxy for healthy gut flora.  We know that they are important, but don’t yet know how to manage the biota for maximal life expectancy.
  5. Vegetable-based diet This review concluded that vegetarians live 3 years longer, but methodologies and results vary considerably.
  6. Meditation This is difficult to evaluate, and data is unreliable but encouraging [ref].  The only careful study linked meditation not to mortality but to telomerase activity.  I confess I am including meditation in the list from my own intuition and experience.  
  7. Intermittent fasting Extends lifespan in mice and lowers mortality in nursing home studies [ref].
  8. Interval training Reputed to be the most efficient path toward cardiovascular fitness [ref], and there is limited documentation of benefit for all-cause mortality [ref].
  9. Donating blood This is another quirky inclusion on my part, but there is data to support it, which I reviewed a few years ago.  
  10. NAC just one study — 30% increase in lifespan of mice
  11. DHEA Lower blood levels of DHEA are clearly associated with greater age and higher mortality at the same age, but the direction of causality is in dispute.
  12. Metformin Prescribed for diabetes for decades, this drug also lowers mortality from cancer and heart disease [planned clinical trial].
  13. Rapamycin The most convincing data available for any supplement for life extension in mice.  Early adopters are beginning to experiment on their own.
  14. Quercetin + Dasatinib (or other senolytics).  Senolytics are the best near-term hope we have for a breakthrough in anti-aging medicine; but the combination of quercetin +dasatinib is not yet discriminating enough to be safe for humans, meaning it kills too many regular cells.
  15. Epithalamin  Very promising data from Russia [ref], both in rodents and in people, but there is no one trying to reproduce them in the West.
  16. Ashwagandha [many benefits, but no mortality or rodent lifespan data]
  17. Selegiline (deprenyl).  In classic studies from the 1980s, lifespan of rats was extended.  Data in humans is contradictory [ref].

Perhaps we should begin with a guess about which combinations are likely to be highly redundant.  In this way, we could cluster together different strategies and condense more strategies into a manageable list.  It might look like this:

  1. Anti-inflammatories (aspirin, ibuprofen, statins, omega 3, curcumin, boswellia)
  2. Blood sugar control (metformin, berberine, gynostemma, chromium)
  3. Social factors (family, employment, wealth, community support, marriage, sex, communing with nature, empowerment)
  4. Mitochondrial supplements (NAC, CoQ10, PQQ, NR, melatonin, glutathione, carnosine, ALA)
  5. Immune support (reishi mushrooms, cistanche, andrographis, goldenseal, echinacea)
  6. Adaptogens (rhodiola, ashwagandha, bacopa, silymarin, pycnogenol)
  7. Telomerase activators (silymarin, astragalus, ashwagandha, horny goat weed)
  8. Senolytics (quercetin, dasatinib, fasting)
  9. Diet (everything from high-protein to high fiber to vegan to paleo in one cluster?)
  10. Limiting and intermittency of diet (long- and short-term fasting, CR, BMI)
  11. Exercise (aerobic, strength, interval, walking, competitive sports, yoga)
  12. Mental focus (meditation, prayer, yoga, tai chi, spiritual practice, cafeine)
  13. Neuroprotective (ashwagandha, rhodiola, ginkgo, melatonin, bacopa, selegiline, gotu kola, coffee, tea, blueberries, chocolate)
  14. Multivitamin supplements (including mega D, mega-C, B12, carotenoids and tocopherols)
  15. Sex and steroid hormones (DHEA, prostaglandin, progesterone, SAMe, testosterone)
  16. Angiotensin inhibitors (Lotensin, captopril, enelapril)

Or—the best of both worlds—we might structure the study in such a way that it can be analyzed after the fact either with individual strategies or clusters of strategies.

Fauja Singh, centenarian marathon runner

The best way to design a study is to start at the end.  I imagine I am two years down the road, taking my first look at results from 5,000 life-extenders.  The first thing I will want to do is to look for outliers. Are there a few people who stand out from the bell curve, aging much more slowly?  If so, what do they have in common? The advantage of this approach is that it gives maximal flexibility in telling us exactly what we most want to know.  The disadvantage is that it is easy to fool ourselves and imagine patterns in a small set of random errors. When there is no initial hypothesis, there is no objective way to calculate a probability that what we find is the result of chance.

Our null hypothesis is that there are no systematic outliers, but only a smooth tail to the probability curve.  If there are a few scattered individuals in 5,000 who are aging much more slowly than the rest, we will not find any common thread in what they are doing, and so we must explain their data as anomalies or mistakes.  If this is our result, it will be disappointing, sobering, but liberating as well. Those of us who are compulsive about one or another life extension strategy can ease our discipline.

But there is a chance we will find something more interesting.  We may find that there are dozens of outliers, that their life extension strategies all overlap in some clear and unambiguous way.  We will then have, for the first time, a solid foundation for our personal life-extension habits, and a clear hypothesis for further experiments.

What are your thoughts?  Please comment.