Though thousands of years old the ancient Taoist tradition of eating mushrooms and other magical substances together with eating less, as some wandering monks practised in India to extend life, is still with us. There are modern religious mystics who believe in the possibility of achieving physical immortality through spiritual transformation as a part of their religious doctrines. They believe that after God has called the Day of Judgment, they will go to what they describe as Mount Zion in Africa to live in freedom for ever. They avoid the term ‘everlasting life’ and deliberately use ‘ever-living’ instead. An example is the Rastafarian and Jamaican singer Bob Marley, who refused to write a will despite suffering from the final stages of an advanced metastasised cancer on the grounds that writing a will would mean he was ‘giving in to death’ and forgoing his chance of living for ever. A group called the Rebirthers believe that they can acquire immortality by following the ‘connected’ breathing process of rebirthing.
The multi-million-pound industry based on anti-ageing treatments is discussed in the next chapter. In 2002 an article in
The American Academy of Anti-Aging Medicine promotes the field of anti-ageing medicine and trains and certifies physicians in this speciality. Their co-founder Ronald Klatz stated that ‘We’re not about growing old gracefully. We’re about never growing old… The leaders of the Anti-Aging movement will help to usher in a new modern age for humanity: The Ageless Society. There is a remedy for this apocalypse of aging, and this remedy comes just in time to save America.’ But there is scientific hostility to its practices and no evidence that what they promote works.
Medical interventions for age-related diseases do result in an increase in life expectancy, but none have been proved to modify the underlying processes of ageing. At present there is no such thing as an anti-ageing intervention. For example at present there is relatively little evidence from human studies that supplements containing antioxidants lead to a reduction in the rate of ageing. The use of cosmetics, cosmetic surgery, hair dyes and similar means for covering up manifestations of ageing may be effective in masking age changes, but they do not slow, stop or reverse ageing.
Nevertheless, there is extensive advertising of anti-ageing products and the public is spending vast sums of money on them, even though in most cases there is little or no scientific basis for their promises and some may have harmful side effects. Some scientists are unwittingly contributing to the proliferation of these pseudoscientific anti-ageing products by failing to participate in the public dialogue about the reliable science of ageing research. There are, for example, advertisements for a treatment which prevents shortening of telomeres and so promotes longevity. Although telomere shortening may play a role in limiting cellular lifespan, there is no evidence that telomere shortening plays a major role in the determination of human longevity.
There are a variety of reports of substances that can extend life. A study of over a thousand men in Holland over 40 years found that those who drank half a glass of wine a day lived about five years longer than those who drank no alcohol at all, and two and a half years longer than those who drank beer and spirits. Herbs such as ginseng, rhodiola and maca have active ingredients that are claimed to suppress ageing. Studies show that a plant compound, resveratrol, can extend the lifespan of yeast, worms, flies and fish but there is as yet no evidence that it helps with humans. Resveratrol appears to mediate ageing effects partly by activating sirtuins. Resveratrol is found in the grape plant and in berries, and it is also a vital component of red wine.
A new star has appeared in the field of drugs that delay ageing in laboratory animals, and are therefore candidates for doing the same in people. The drug is rapamycin, already discussed in relation to TOR, its target, and which is in use for suppressing the immune system in transplant patients and for treating certain cancers. It can increase the lifespan of nematodes and fruit flies, and recently increased the lifespan of mice significantly. Given to the mice when they were 600 days old, it increased their lifespan by about 30 per cent. It has not been tested on humans and this should be done with great care because of its effects on the immune system. Studies in mouse models indicate that weakening the pathway on which rapamycin acts leads to widespread protection from an array of age-related diseases.
Aubrey de Grey is a scientist who, contrary to the standard scientific view, believes it will be possible to significantly prevent ageing. He calculates that two thirds of the people who die each day worldwide die of ageing, based on a definition of ‘death from ageing’ as death from causes that afflict the elderly more than young adults. He claims it will be possible to reduce the effects of ageing so greatly that humans will have a 50/50 chance over the next thirty years of being effectively immortal. He believes regenerative medicine may be able to thwart the ageing process altogether within that time. He works on the development of what he has termed ‘Strategies for Engineered Negligible Senescence’, a tissue-repair strategy intended to rejuvenate the human body. One basis for his claim is that mitochondria are damaged due to free radicals damaging their DNA, and they cause their host cells to secrete more damaging free radicals and so damage other cells. He believes that it will be possible to obviate the damage in the mitochondria’s DNA. He also claims that many age-related degenerative diseases are linked to inadequate lysosomal function. Lysosomes are small vesicles in cells whose contents can destroy almost any unwanted cellular material—but not quite all, and this shortfall is known to underlie various age-related problems, including cardiovascular disease and macular degeneration. Alzheimer’s disease involves the failure of unwanted proteins to be destroyed by other waste disposers both inside and outside the cell. Amyloid protein aggregates, a possible cause of Alzheimer’s, are made from a normal protein that has been altered. An anti-amyloid vaccine could be helpful as the immune system would destroy the aggregates. A clinical trial along these lines was stopped when one individual became very ill, but a new trial has now reached phase 3.
In order to prevent ageing in this way, it will be necessary to repair, or else render harmless, numerous types of accumulating molecular and cellular damage so that the age-related pathologies caused by excessive amounts of that damage are prevented. In various cases, this requires manipulating genes, which at present would need to be done in the fertilised egg. And then the researcher would have to wait more than a hundred years to see if that individual survives that long, and suffers no problems from the manipulation to the genes. This is a most unlikely scenario; it is far too risky, and few if any researchers would live to see if their treatment worked. Thus, as de Grey accepts, the comprehensive application of regenerative therapies to ageing within a few decades relies on the development of safe and highly effective somatic gene therapy, which currently remains a daunting prospect. Additionally, an effective panel of therapies must address cancer, extracellular damage causing pathologies such as heart disease, and viral and bacterial infections. Finally, it is also far from clear that preventing cellular ageing would prevent cognitive abnormalities such as dementia and depression occurring, and de Grey acknowledges our ignorance of such matters.
In the UK the life expectancy for men and women is now 77 and 82, and a young man in his 20s today is expected to live five years longer than a man in his 50s. There are estimates that one in eight UK citizens now aged 35 will live to over 100. Half of the children alive today in countries with high life expectancies may celebrate their 100th birthday. In the UK, with a population of 61 million, 400,000 are over 90 and there are more pensioners than children under 16. The small village of Montacute in Somerset has the highest life expectancy for men in Britain, possibly because many of them grow their own food and work hard at it. In the USA, male life expectancy is 75 and female is 81. There is expected to be an increase from 4 million to 20 million over-85s by 2050 in the USA, at which time there may be nearly one million centenarians. At present about 10 per cent of the world’s population is over 60 but by 2050 it will be 20 per cent, and the elderly will outnumber children worldwide. Women outnumber men at age 100 by 5 to 1. Japan has the current highest life expectancy for females, estimated at 85, and Iceland for males, at 80 years.
There are currently about 40,000 centenarians in the United States, and they are the fastest growing segment of the population. Traditionally scientists believed that most people who live to 100 experience a ‘compression of morbidity’—that is, they do not develop common age-related chronic illnesses like diabetes or coronary disease until very late in life, if at all. However, more recently, investigators have found that nearly one- third have in fact suffered from long-standing chronic illness, in many cases for 15 years or more, before turning 100. What they experience is a compression of disability: they avoid major disability and require little or no
