It goes without saying, of course, that there is little if any point in advocating strategies which would lead to a longer life span were this to be in anything other than a reasonable state of physical and mental health. The emphasis of all the evidence outlined in this book, the milestones and markers in the search for life extension, will therefore be on those methods which offer the greatest prospect for a healthy longer life.

The aim of 'more years to your life' appeals to many, but equally there are those who insist that they are more interested in adding 'life to their years'. I suggest that both of these aims can be met by the most proven of the methods which I will explain in later chapters - calorie restriction.

Evidence not recommendation
I want to make it clear, though, that the approaches which I outline and explain are not recommendations which you are being urged to follow. The concept of life extension and the evidence which has accumulated from the work of many researchers in this age-old quest will be explained, but any attempt to apply such methods must be a personal decision and should take into account those individual variables which make you unique, including your current health status and predispositions, as well as your individual biochemical, structural and psychological make-up.

During the ageing process there are a number of well researched interacting processes at work, some of which at least can be modified and slowed down by simple natural means.

Natural?
What is natural in this context is hotly debated, not least by those conducting the research into methods of increasing life span. A working definition might be: 'anything which retards, modifies, improves, or in some way influences for the better, those processes which lead to ageing and death'. A course of action could be thought of as 'natural' if it were to involve the use of methods or substances which are a normal part of the body's economy (dietary modification or supplementation, for example) but which do not involve the use of synthetic materials, or approaches which cannot be applied in total saftey (surgery or hormonal treatment, for example).

A summary of current methods, so far used experimentally on animals in order to evaluate their effect on life extension, can help to highlight those methods which can reasonably be considered 'natural'

Dietary strategies

1. Alteration of individual components of diet (fat,carbohydrate,protein)

2. Increase of antioxidant nutrient intake

3. Increase in vitamins and/or mineral intake

4. Adequate nutrient intake accompanied by calorie restriction strategies

Drugs, hormones and/or specific nutrients used pharmacologically

1. Various natural or synthetic hormones

2. Various synthetic antioxidants

3. Specific amino acids used pharmacologically* (e.g. arginine, ornithine)

* This is pharmacological in the sense that the nutrient is used in the fashion of a drug rather than a nutritional supplement, and where its specific supplementation has a more powerful effect. For example, the taking of heroic quantities of vitamin C (up to 50 grams when used pharmacologically) for its antibacterial and/or anti-viral activity is not the same effect as would be anticipated from the eating of an orange with its relatively small vitamin C content, or even of supplementing a few grams in order to enhance immune function. Nor would the taking of arginine in large doses for its anticipated effect on the pituitary gland be the same as the effect from eating a protein food of which arginine is a natural constituent.

Surgical methods

1. Surgery to pituitary gland

2. Removal of testes in males

3. Immunological intervention strategies

Other methods

1. Altered exercise patterns

2. Methods for altering core temperature

Which of these methods is natural?
All of the first list might be considered as natural inasmuch as changing dietary patterns seems to be a process many people adopt for a variety of reasons. To many people dieting in the hope of increasing the length of their life might be considered just as suitable and natural an objective as slimming or weight training.

Results to date favour using dietary restriction methods (method 4) for this has produced some truly remarkable life extension results. Method 2 has also had its successes.

Readers familiar with the traditional methods used in naturopathic medicine (in Britain, America and Germany) will not be surprised to discover that many of the benefits which have been ascribed to periodic detoxification diets, fasting methods and nutritional approaches to health, are closely related to the findings of half a century or more of animal experimentation involving dietary restriction, periodic fasting and related methods, leading as they do to a longer, healthier life.

None of the second list is really natural, with the exception perhaps of some of the ways in which method 3 on that list is employed (this being the most successful and widely employed method in this category).

All of the third list fail the test for naturalness (these being relatively unsuccessful and certainly not suitable for selfapplication). While both the approaches in the last list are natural, only method 2 has had notable success.

The most successful options
As suggested above, far and away the most successful method of increasing the life span of a wide range of animals (including mammals) has been the use of dietary modification in which adequate nutritional supply of essential vitamins and minerals etc. is ensured while a reduction in calorie intake is introduced. This approach has been described as 'undernutrition without malnutrition'. I describe in subsequent chapters the fascinating research conducted into this. Research which has shown amazing increases in normal, active, life span of up to 300 per cent in some species, accompanied by a dramatic reduction in the diseases usually associated with ageing, such as cancer and autoimmune disease (with the frequent observation of the healing of these diseases in animals already affected).

I shall explain the ways and means of translating and applying these concepts to the human condition, as well as a number of other interesting life extension possibilities which have emerged from research, such as nutritional stimulation of growth hormone production from the pituitary gland, the use of antioxidant nutrients and methods for lowering core temperature levels.

But are these approaches really applicable to humans?
Two of the major researchers into the effects of dietary restriction on life extension are Richard Weindruch Ph.D. and Roy Walford MD (the former is a researcher at the National Institute of Health, Bethesda, Maryland, and the latter a professor of pathology at the University of California, Los Angeles).

They say: 'We think that there is a very high order of probability that animal data are translatable to humans, in terms of retardation of ageing and life span extension as well as disease prevention.' (The Retardation of Aging by Dietary Restriction, Charles Thomas, Springfield, Illinois, 1988).

Can we assume that animal studies are relevant to humans?
Much of the evidence which has been accumulated in support of life extension through dietary modification involves animal experimentation, but a noted expert, Sir Kenneth Blaxter (writing in the Journal of Nutrition and Reproduction International, 1979) said: '. . . the conclusion seems to be inevitable that the proper species to use in the study of the nutrition of man is man himself.'

For conclusive results of the effects of diet on longevity in humans, with the purpose of proving or disproving the animal evidence gathered to date, a study would need to run for about 100 years, and would require absolute adherence to the diet being tested. This is just not possible. So, to be practical, it is necessary to look for options which are within our reach.

Can we believe animal study evidence at all?
To answer this question we need to look at three things. First we must ask whether we should even honour such experimentation by quoting it, giving it credence, and taking note of its findings. Second, if we can get past these doubts, we must be reasonably sure that the results are also applicable to humans, before we try to use the findings. Third, we must look for alternatives - cell cultures, for example, and evidence from humans who have for many years followed patterns of diet which approximate in some way to the animal studies.

Leaving aside the question of applicability to the human condition, there is a rising tide of feeling against viviSsection (physical experimentation on living animals). However, insofar as life extension experiments are trying to find ways of prolonging the lives of the participant creatures it can be argued that what is being done is in direct contrast to the normal fate of experimental laboratory animals, where life span tends to be shortened rather than lengthened. I accept, though, that even this argument would not convince someone who abhorred animal experimentation on moral grounds, whatever the comfort of the animals, or any positive outcomes their might be, or even the importance of the information gathered in this way.

However, many believe that since the experiments quoted have already been carried out, and since the evidence is of importance to a great many people, we should make ourselves aware of the results, without necessarily condoning the methods used.

Alan Hipkiss Ph.D. and Alan Bittles Ph.D., writing in Human Aging and Later Lik (edited by Anthony Warnes Ph.D. and published by Edward Arnold, London, 1988), have their own views on the subject:

Given that dietary restriction is the only factor known to increase longevity in any animal model, and given its inapplicability to the human condition, one must question whether information appropriate to human ageing can be obtained from animal models. On the other hand, animal studies obviously have their place in comparative research programmes into ageing.

I would strongly refute the statement that dietary restriction methods are 'inapplicable' to the human condition for, as we will see in the chapters that follow, a number of strategies allow us to incorporate aspects of the methods used in these animal studies into our lives if we so choose. I also confess to confusion when told in the same paragraph that animal studies are and aren't useful as evidence. Certainly Walford and Weindruch take a very different position as to the value of information to be gained from animal research. And they are supported by the views of one of the great nutritional pioneers of this century, Sir Robert McCarrison.

Some of his most important research focused on the various dietary patterns followed by different ethnic groups living on the Indian sub-continent, and he found that in feeding these similar patterns to rats that he could produce amazing confirmation of the effects of their diets on the health, physical size and longevity of the different groups. He tells us of these experiments and the results in his remarkable monograph Nutrition and Health (republished by the McCarrison Society, 76 Harley Street, London W1 in 1982 having first been published by Faber and Faber in 1943):

. . . the frequency with which results observed in rats are applicable to man is remarkable - a fact which will be the better appreciated from the examples which I will place before you. Without such experiments on animals the vast amount of knowledge revealed by them would be hidden from us and we would stiJ1 be in ignorance of the kind of consequences to expect in man from his continued use of food of faulty constitution. We would, moreover, be in ignorance of what a properly constituted diet is.

P. Vincent Hagerty Ph.D. of the University of Minnesota, writing in Contemporary Nutrition (March 1981), states that choice of animals for experiments is often dictated by convenience and economics rather than sound biological principles. He points to varying results in nutritional testing involving humans and specific animals, and even between different strains of the same animals. He also questions the care with which other factors such as stress are considered when nutritional tests are conducted, especially in relation to rats. However he concludes that: "The contribution of animal models to understanding alterations in biochemical and physiological processes in complete nutritional stresses has been invaluable."

If precautions are taken regarding selection of species, strains, diet, duration of experiments, adaptation to the diet and a variety of other criteria, useful information can be derived. The choices open to scientists seeking the secrets of prolongation of life seem to fall into three possibilities:

• To use animal studies

• To try to deduce evidence from human experiments (difficult but not impossible)

• To use human tissue (cells) in culture dishes to see what happens to them over time and under different conditions.

It is towards the last of these choices which some researchers are moving, since it is now known that when cells are carefully cultured, in laboratory settings, providing that they are ensured optimal conditions and nutrients, they continue to divide and reproduce for a predictable number of times until they begin, of their own volition, to age.

As Drs Bittles and Hipkiss put it: 'The fact that human cells derived from the skin or lung, such as fibroblasts, undergo senescence [ageing] in culture shows that ageing has an intrinsic [built in] cellular basis and is not solely a consequence of defective intercellular communication (hormonal influence etc).' Since the cellular changes seen in culture situations are very similar, if not identical, to those seen in animal studies (as well as to those found in the cells of people who have aged normally) it seems reasonable to accept evidence from both sources (animal studies and cultured cells) as a reliable basis upon which to build a picture about this fascinating subject.

Resistance to the evidence
Much to the anger of Drs Weindruch and Walford there seems to be a built-in conservatism in medicine which refuses to take seriously the mounting evidence, to which they have added so much, and the contention that it probably relates to humans, largely on the grounds that animal studies do not conclusively prove anything in relation to the human situation. Animal studies, across the spectrum of species, do support the argument for dietary strategies being almost certainly applicable to the human condition and yet such evidence remains inconclusive according to many conservative scientists.

Weindruch and Walford counter this sort of argument by pointing to a wide range of medical methods which are in current general use and for which there is no overwhelmingly 'conclusive' evidence showing that there remains no doubt as to either value or safety. As examples they cite the continuing controversy relating to the relative importance in cardiovascular health of lowering cholesterol levels via diet or drugs. This debate has led to changes in advice for severa1 decades, and still remains unresolved, but it has not prevented authoritative medical guidance on the subject being given to the public time and time again.

Equally equivocal is the new-found medical acceptance that diet is responsible for not less than 40 per cent of all cancers and that prevention via dietary manipulation is a highly desirable objective (increased complex carbohydrate, fresh fruits and vegetable intake and reduced fat, meat and refined carbohydrate intake, a strategy not dissimilar to that needed for lowering cholesterol levels). Since exposure to any carcinogenic factor might precede cancer by as much as 25 years there is no adequate experimental method whereby unequivocal proof of this dietary connection can be made, short of 25 to 30 year long research studies.

This shortfall in certainty has not prevented national and international medical and health organizations from making firm recommendations as to what is and what is not a sound dietary approach to cancer prevention.

Nor, it can be argued, should such a shortfall in absolutely conclusive evidence be the reason for failing to recommend safe nutritional life extension strategies (which incidentally also produce a lowering of cancer incidence and cardiovascular disease in animals). The argument that it is prudent and 'scientific' to wait until we know for sure can be countered by pointing out that sitting on the fence, waiting for evidence which is totally incontrovertible, is far from being a really neutral stance, argue Weindruch and Walford.

Staying with the cancer example, we can see that for authorities to have failed to give publicity to the general consensus of a diet/cancer connection and to not have advocated implementation of an anti-cancer dietary strategy, would in effect have been a policy decision in and of itself.

This is not a case where neutrality means little, for if the evidence pointing to a probable connection (diet/cancer) was subsequently found to be correct, incontrovertibly, the neutral 'hands-off approach could have resulted in an uncountable number of deaths, many of which might have been prevented. Much that we do has to be based on assumptions, made in the light of the evidence available to date, leading us to believe in the probability and likelihood of something being so.

This is where art and logic intervene in the scientific argument, and this is why life extension potentials can be seen to be 'probable' if the animal studies or culture results are taken as guidelines. To state, as has been done by leading members of the study of ageing who are opposed to the making of any recommendations until certainty is apparent, that: 'Dietary restriction will certainly work on rodents (increasing life span) but there is no certainty that it will work in humans' is tantamount to saying that this area of research has to comply with criteria of proof which are not required or necessary in other areas of science and medicine.

But there is another source of confirming evidence, for the fact is that there are population groups who have followed for centuries pattems of eating similar to those applied experimentally to animals, and the results are precisely what would be expected, they live far longer and are healthier than the rest of us. These will be described in detail in later chapters.

It is therefore reasonable to suggest that the application to humans of the methods derived from evidence gained from animal studies can, along with other strategies, lead to safe and healthy life extension, naturally.

Other life extension options
Over the past ten years or so the taking of amino acids supplementally in order to stimulate production by the pituitary gland of growth hormone has been widely employed in life extension programmes, mainly in the USA. The use of this method was given enormous impetus by the best-selling book 1~ Extension by Durk Pearson and Sandy Shaw (Nutri Books, 1983) spawning in its wake a mini-industry in supplement production and sales.

More recently, in 1990, medical studies involving the injection of growth hormone into the muscles of elderly males has shown quite dramatic benefits, and this has validated much of the claims made for the earlier nutritional approach, which is a degree or two more 'natural', if that much-abused word can be applied to any attempt to manipulate hormonal secretions. The arguments and evidence for this approach will also be outlined in detail later in the book. Antioxidant supplementation will also be covered, rounding out the most successful nutritional approaches to life adension to date.

One other method, of proven value in animal studies, which deserves attention, is that of the reduction of core body temperature; something which is accompanied by a slowing down of the rate of metabolic activity (as seen in hibernating animals) and which also occurs when we are in a state of deep rdaxation and meditation.

Before coming to the research in question, and before considering just what we can do ourselves to emulate the truly unazing extensions in life span achieved to date in animals, we must spend some time getting to grips with what is thought to happen as we get older, the ageing process itself.