HumanaNatura’s principal focus is the health and quality of life we enjoy each day. Still, as a prelude to talking about living longer, who of us can say they are indifferent to the length of their life as well?
Ancient philosophers wrote about the trade-off between living well and living long, and wondered which was more important. The wisest of them – who could see that new and higher human life waited beyond the excesses and preoccupations of their times – knew that this dichotomy was a phantom only.
For them, living well and living long were consistent and even complementary goals. The long life and the good life were aspects of the same complete, more balanced human existence they knew was available to us.
As we acknowledge this ancient realization, we must not overlook the many advances in human science that have occurred since antiquity. We might lament that the diffusion of modern scientific understanding in society, like the advance and spread of older knowledge about living well and long in ancient times, has not kept pace with science’s recent dramatic expansion and progress. But this only underscores our potential to make important improvements in our health and quality of life, in our time and building on the ideas and practices of the ancients.
With our modern knowledge is the opportunity to raise the ancient art of living well and long to true science. In this article, we will provide an extended survey the current science of living long, of human longevity, knowing in advance that this will be a survey of much of the new science of living well too.
If you are acquainted with HumanaNatura’s health principles, you will find themes and findings here that are familiar, but perhaps some new ideas to consider too.
The Science Of Longer Life
We should start a discussion of the science of longevity by saying that scientists have learned much in recent years, and still have much to learn. There are a number of important new theories of longevity, which we might see as competing, but which ultimately will be unified and integrated as part of a general science of health optimization. All these theories aim to explain, and ultimately forestall, human aging and degeneration. But none of them are settled science just yet.
Reminiscent of ancient discussions, today’s theories of aging once again consider and invoke contemporary assumptions about quality of life, and the potential for trade-offs between living well and living long, as they probe the length of life available to us. In a full retracing of this old debate, the subtlest of today’s scientists understand that the dichotomy between longevity and life quality remains largely, though perhaps not completely in its extreme, an imaginary one. Then and now, our inclination to see living well as nearer to either to urbanity and excess, or to nature and moderation, ultimately drives the strength of this dichotomy.
As we gradually move to a unified science of health, encompassing life quality and longevity, almost all scientists would agree that genetics will play a large role in the formulation of this science. However, this is not to say that we are each held hostage to our genes, or that the length of our individual life is largely determined at birth by our genetics, or that we have little control of our actual lifespan, as some are apt to think.
The importance of genetics in a modern science of aging has more to do with the fact that our genes ultimately create the structure of our bodies, including the physiological pathways that are critical to our health and quality and length of our lives. In other words, our genetics create important and specific vulnerabilities and opportunities for health and longevity in each of us. We are all subject to these genetically derived structures, although some of us clearly have greater health sensitivities than others.
There are five primary scientific theories or models of aging and longevity today: 1) Dietary influence, 2) Stress & oxidation, 3) Hormonal interaction, 4) Telomere dynamics, and 5) Selection mechanisms. Let’s summarize and consider each of these theories briefly:
· Dietary influence – the idea that our diet is important to longevity is not new. The science linking diet and longevity was preceded by centuries of popular intuition that a moderate diet was essential to both daily health and long life. But intuition is not science, and some of this earlier intuition is proving incorrect under the scrutiny of modern science. What we know now is that when many organisms have their diets restricted, they live much longer and generally maintain their natural vitality throughout most of this added lifespan. We also know that severely restricted diets, however, reduce the fertility of these organisms and thus their quality of life in at least some sense. We still do not understand the impact of restricted diets on human longevity, or human fertility, or the impact of selective food restrictions, although comparative and longitudinal studies of people living on restricted diets are well underway.
· Stress & oxidation – after diet, the science of stress and physiological oxidation, and their effects on longevity, is most widely known. In fact, it is hard to scan the popular health press and not see articles recommending we counter “free radicals” in our bodies with anti-oxidant therapies to achieve a longer life. What many people do not know is that oxygen-free “radicals” (also known as oxidants) are a natural by-product of cell metabolism, and that the healthy body is well equipped with enzymes to control excessive build-up of these free radical oxidants. The body contains these enzymes, as you may know or have guessed, because oxidizing radicals are damaging to the body and accelerate aging. There is also little question that environmental stress (including lifestyle and occupational stress) increases the presence of free radicals and the harm they can cause, including their potential to shorten life. The control of chronic stress is thus an essential strategy to minimize the harm and threat to longevity caused by excess oxidants in our body. The effect of anti-oxidant supplements in increasing the body’s ability to control free radicals, however, is much less certain. Many scientific studies suggest it is very likely that a natural human diet (see the HumanaNatura natural diet program for an explanation of this term) provides a sufficient and readily absorbable supply of the anti-oxidants to control normal oxidation, and even may help to moderate free radical production in the first place.
· Hormonal interaction – slightly less well known is the scientific research on human hormones and their potential impacts on aging and longevity. Hormones such as human growth hormone, testosterone, estrogen, and progesterone have been used successfully to reverse disease conditions associated with aging, such as bone loss and other forms of chronic tissue wasting. These results have led some scientists to hypothesize that hormonal supplements could be used to counter aging more generally and thereby increase longevity. The results of animal studies using hormones to forestall aging and prolong physical vitality have been inconclusive so far, however. Some studies have suggested, perhaps unsurprisingly, that significant side effects may result from hormonal use and that these supplements could actually reduce life span. As was the case with anti-oxidants, it is again likely that a healthy body produces all the hormones we need, in the correct proportions, to live a long life. Nature has had a billion years to balance the costs and benefits of hormonal use, even if its optimization is more species than individually focused.
· Telomere dynamics – now we’re getting into much less well known science and theory on aging. It is been known among scientists for some time that many cells can only reproduce about fifty times, leading ultimately to physiological aging and the death of the organism, but scientists weren’t sure why cell reproduction was limited in this way. More recently, the shortening of our DNA’s telomeres has been established as the most likely contributor to this cellular limitation. Telomeres are the tips of repeating code at the end of our chromosomes. As cells reproduce naturally through division (or artificially through cloning), their telomeres shorten, eventually becoming so short that further cell division is inhibited (perhaps by the body’s chemistry in an attempt to limit increased risks of mutation and prevent the formation of cancers). On the other hand, it has also been observed that certain cells are able to divide without telomere shortening through the use of special enzymes. This has led scientists to hypothesize that more general use of telomere-protecting enzymes could lengthen cell reproduction and delay aging. Unfortunately, the early studies testing this approach have not been encouraging, and the strategies employed so far may well increase the incidence of cancer formation, shortening rather than lengthening our average lifespan.
· Selection mechanisms – least well understood, but perhaps ultimately most important to a unified understanding of human health and longevity, is the science of natural selection. Included in this general science is selection’s crafting of our physiological mechanisms for health, and the specific structures, limitations, and opportunities we have for longevity and vitality during our lives. As alluded to before, our genes do not wholly determine our individual lifespan, but they have created us as a species and as individuals. Evolutionary biologists seeking to understand the impact of selection on our longevity start by asking: why live long at all? What is in it for our species, and our genes, to have us live to a certain average age? And what aspects of our biology are consequences of selection pursuing these special advantages? It is important and worth noting that scientists have roughly doubled the lifespan of simple insects through repeated laboratory selection for long-lived variants. The mechanisms and implications for humans of this change in longevity are just beginning to be understood, but appear ground-breaking and will be covered in the next section.
Important Learnings In Longevity
To begin to integrate these scientific theories, it might be worth thinking of genetics as the beginning, rather than the end, of an eventual science of longevity. Much follows from this starting point, including a new understanding of the physiological pathways they create that support human health and longevity, as well as the resulting strategies essential to optimizing both our health and lifespan.
Genetics, of course, are the result and key medium of biological evolution. If we reflect on evolution and selection, in nature and in human beings, we normally would expect specific genes to be responsible for each of our adaptations and bodily structures.
It is an easy and familiar trap to think about our bodies broadly, and fail to see the genetic trees underlying our anatomical forest. In truth, selection always progresses via an amalgamation of specific genetic mutations. When we see the physical or physiological attributes of an organism, we should expect to find specific genes and resulting mechanisms that cause the attribute, rather than having the whole organism devoted to the attribute’s expression (as many thoughtful people believed from ancient times and until just recently).
When we talk about health and longevity being based on our genetics, we mean that there have been past genetic adaptations that influence human lifespan and that these adaptations are fairly few in number. These adaptations are still complex, but they are also identifiable and specific, and cause predictable features and consequences in our bodies.
This specificity and predictability of the genetic drivers of longevity are exactly what we are beginning to see revealed, as science starts to probe the drivers of aging. Scientists are narrowing in on just a few genes and biochemical processes as the likely key contributors to a long and healthy life. While some individuals are more likely to live longer because of their genes, much more is common between us. Almost all of us have the potential to influence our lifespan – to live longer and better.
Below are a summary of current longevity research findings, most based on or involving evolutionary science and genetics, and microbiology:
· Longevity as adaptation – as discussed before, scientists are deepening our understanding of human longevity as a product of evolutionary selection. In this light, our genes can be seen as mechanisms of longevity, as they are for many of our other attributes, with specific genes crafted to optimize the length of our lifespan against other design requirements that, in the aggregate, best promote overall gene survival. Our human adaptations have produced a relatively long lifespan, likely reflecting the utility of having elders in society (although other explanations are possible). In any case, our natural and naturally long lifespan is not arbitrary, and is potentially alterable by optimization of the physiological pathways that foster our natural longevity.
· Health understood genetically– as scientists narrow in on the key genetic and biochemical drivers of longevity, the importance of a healthy diet, lifestyle, and environment is becoming both validated and better understood. Research continues to uncover the physical mechanisms that drive our health and their linkages to specific genetic and biochemical pathways essential to human health and longevity.
· Sirtuins – if you haven’t heard about sirtuins yet, now is a very good time. Sirtuins are a name for a family of genes that scientists are focusing on in their search for the keys of longevity. We are just beginning to understand how sirtuins work and what they drive physiologically, but it looks like a good bet that they both promote daily health and lengthen our lives when they are activated. More on sirtuin activation strategies in a moment.
· Longevity therapy – animal experiments to increase longevity through diet restriction, drugs, and selection techniques have produced interesting early results, with lifespan increases generally in the range of 10-50%. Therapies for humans, however, are still a ways off, for both practical and bioethical reasons. The current life-extension drug of highest focus is Resveratol, which activates sirtuins and may extend life. One obvious shortcoming in all human life extension experimentation is our already relatively long human lifespan. It could literally take decades, even generations, to fully validate potential life extension therapies for humans (a long time relative to each of us seeking longer life individually).
· Laboratory vs. human results – it is worth noting that short-lived animals such as mice or insects, so often used in longevity research, have different genetic and biochemical structures than longer-lived animals like humans. These animals have evolved to achieve species flexibility and adaptation through rapid metabolism and regeneration, making them useful in the laboratory. Humans, on the other hand, have evolved to adapt by focusing on biochemical and social stability (and adapt now as much or more through cultural learning and teaching as reproduction). What this means is that it is quite possible that longevity therapies that work well with short-lived animals may have a significantly diminished impact in humans and other longer-lived animals.
· Metabolic stability – building on this idea is recent research suggesting that metabolic stability may be more important for health and longevity than metabolic deceleration, especially for long-lived organisms like humans. Earlier thinking was that our metabolic rate, and our corresponding rates of oxidation and creation of free radicals, was the largest determinant of physiological aging and longevity – and slowing everything down seemed like a good idea. It now appears that the stability of free radical production, rather than their actual rate of production, is more closely linked with health and extended lifespan.
· Right amount of stress – though it may seem counterintuitive, newer research suggests that mild stress may be better for your health and longevity than low levels of stress. The reason for this is that mild stress appears to activate your sirtuins, promoting your natural defensive biochemical pathways and therefore physiological health. If you think about it, mild stress actually may be more natural a state than low stress environments, and may trigger our body’s natural health-inducing mechanisms more strongly. In nature, we were apt to be on the move and moderately challenged in our daily life.
· Plant sirtuins – in case you were wondering, it is not just animals that have sirtuins. Plants have them too. In fact, ingestion of plants rich in sirtuin-created compounds may be important to our health and longevity. And, as is the case with humans and animals, food plants under mild natural stress may have the most active sirtuins and therefore be the most health-promoting compounds. For this reason alone, organic produce may be healthier for us (and is likely a good health bet for other reasons too).
· Insulin production – it has been known for a long time that excessive production of insulin was a key contributor to reduced health and longevity. In addition to promoting obesity and other forms of physiological degradation, excessive insulin appears to curtail sirtuin activity, inhibiting the natural biochemistry of human health and longevity. This becomes just one more of many important reasons to control your insulin levels through a natural diet and exercise program.
· Fat mass -a person’s total amount of body fat appears more related to longevity than food intake. The reasons for this are still being studied, but a good guess is that reduced fat means fewer stored toxins, which generally end up in our fat cells, as well as more stable long-term insulin, free radical, and hormonal production in our daily lives.
· Calorie restriction – yes, back on calorie restriction. Recent research is bearing out the effectiveness of moderate calorie restriction in humans, especially when they involve diets that are insulin-stabilizing and sirtuin-activating. Moderately restricted diets may actually lead to less efficient metabolism, but afford much cleaner metabolism than unrestricted diets – moderating and stabilizing free radicals, oxidants, and insulin levels.
· Happiness – returning to our earlier discussion that living well and long are complementary goals, studies of centenarians (people living over 100 years) reveal one important, common, and cross-cultural attribute of these long-lived people: optimism. Centenarians are much more optimistic than the population as a whole, and report having felt that way throughout their lives.
Implications For People Today
As mentioned before, there has been a great deal of progress in developing a true and more complete science of human health and longevity. Various theories of aging and research findings are slowly fitting together to form a unified understanding of health promotion and life enhancement. But we have a way to go and all of our conclusions still need to be made tentatively, even if we have reason to be hopeful and can see future understanding taking shape in our time.
Certainly there are evolutionary constraints on our human lifespan, but these constraints may be mitigated through lifestyle choices today and longevity therapies in the future. In both cases, it is worth asking: If we choose a longevity strategy today, or a longevity therapy in the future, what will the trade-offs and side effects be? Will we really be able to live well and long?
We know already there are life choices that promote, but do not guarantee, a good and long life. Ancient ideas of moderation and simplicity work as well today as they have for centuries, and can even be improved by our more complete modern understanding of natural human health and vitality.
If you are interested in living well and long, today, while we all wait to see what new techniques and understanding science will bring tomorrow, here are several strategies to improve your health and life today, and perhaps extend it further into the future:
· Health management – the most important idea in our discussion and emerging health science is that our health and longevity are inextricably tied together. While you may come from an ancestral line studded with centenarians, or not, this fact only hints at a possible lifespan and is not a guarantee or a sentence. Lifestyle matters a great deal in our lifespan. And of course living long is only half the game of life – let’s not forget living well. In truth, we can pursue both goals, but only through a deeper understanding and managing of the contributors of our natural health and well-being. In health, we can create longer life and enjoy better lives for ourselves and those in our care.
· Physical environment – while we have spent most of our time in this article talking about our internal environment (our genetic and biochemical processes), it is also critical to remember that our external environment plays a large role in longevity and quality of life too. Important factors in our physical environment include sanitation, food and environmental quality, physical safety, freedom from excessive stress, open space and access to nature, timely and proactive healthcare, and an extended, supportive network of family and friends. All these environmental factors are essential to a longer and better life.
· Natural diet – an essential strategy to extend and enhance our lives is adoption of a natural diet (see the HumanaNatura natural diet program for detailed information). This strategy involves following a diet that approximates human eating in nature and is consistent with research showing that lower (but not low) calorie and carbohydrate diets are associated with longer and higher quality life. A natural diet reduces insulin production and is metabolically moderating and sirtuin activating, combining to lower important health risks and foster critical health and longevity-promoting biochemical processes.
· Metabolic moderation – based on current research, strategies to lower metabolic activity and/or to offset metabolism via anti-oxidant supplements (such as vitamin E) appear less important to health and lifespan promotion. Instead, strategies to moderate metabolism and free radical and insulin production appear more likely to promote health and longevity. A natural diet is thus well equipped to promote metabolic moderation, while providing a rich supply of anti-oxidants for health and long life.
· Organic produce – I’m sure I’m not the first person you’ve heard suggesting that you eat organic to live longer, but let me do it for a different reason. In addition to keeping toxic compounds out of our outer and inner environments (i.e. fostering the health of soil and tissue), you should eat organic produce because it is under mild stress (the natural condition of living things). Remember that mild stress activates sirtuins, which plants have too, promoting healthy biochemistry in the foods you eat. Eating healthy, mildly stressed produce appears very good for you. Chemically treated produce, on the other hand, is protected from the environment and is under almost no stress. It looks better on supermarket shelves but comes from plants with less active sirtuins and likely fewer health-enhancing and life-extending compounds.
· Active lifestyle – a balanced, active human lifestyle seems like another good bet to actively promote a long and good life, activating our sirtuins and other drivers of physiological health. The mild or moderated stress that comes through sensible work, family, friends, community, daily exercise, creative activities, and contact with wild nature appears health enhancing and life extending. Low and high stress lifestyles, by contrast, appear much less healthy. This, it may well be time to get off your mountaintop, or out of your high-rise office, and down into the streets and lanes where community and healthy human life await.
· Optimism – scientists don’t fully understand the linkage between centenarian longevity and their more pervasive and lifelong optimism but suspect their positive attitudes moderate stress and promote healthy chemistry. Are there certain people genetically pre-disposed to both optimism and long life? No one knows, but why not work on being happy already. In all seriousness, you may have much more personal power to live a good, long life than you realize. The old parable about changing our attitude when we cannot affect our circumstances may be just what we need to consider. Often, a change in attitude is even sometimes all that may be needed to change our circumstances, favorably and permanently.
I hope this survey of the current science of longevity has been interesting and informative, and will help you consider your own strategies for living a good, long life.
None of us can be honestly indifferent to the prospect of having a long and healthy life, but many people remain poorly equipped for pursuing these goals, and few may still understand that they are indeed complementary, rather than competing, human preoccupations.
Mark Lundegren is the founder of HumanaNatura.
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