Tom Shakespeare: Still seeking the elixir of life? Just don't expect it at the doctor's

You will know it has been a busy time for breakthroughs, if you have been paying attention. On Wednesday, we learned that mega doses of vitamin D could halve the risk of cancer. Before Christmas, Mayo clinic researchers reported that green tea might cure leukaemia. In Alabama, research with eye-cell implants reduced twitching in Parkinson's patients by up to 48 per cent. And in San Diego, a study has identified the genetic mechanism by which insulin metabolism is disrupted by high fat diets, causing type-two diabetes. The worried well will feel a wee bit better about our future.

It is not all good news. The San Diego research was conducted on mice, and scientists are a long way from proving that it's relevant to humans. There were only six patients in the Alabama study, and four in the Mayo research. Meanwhile in Holland, a clinical trial has proved conclusively that bee stings are not a cure for multiple sclerosis. And we also learned that Professor Hwang Woo-suk faked his stem-cell research breakthrough in Korea. The news value of medical breakthroughs can go down as well as up.

The quest for miracle cures has a long history. Five hundred years before Harry Potter, alchemists were busy searching for the philosopher's stone that promised eternal life as well as gold, while the masses resorted to holy relics or herbal remedies to combat disease. It took a while for doctors themselves to deliver concrete benefits. The germ theory discoveries of Pasteur and Koch in the late 19th century, the invention of aspirin in 1897, followed by the development of sulphur drugs and then pencillin, made biomedicine pre-eminent. Now the West's cultural obsession with youth, health and longevity dominates both news and lifestyle coverage and drives biomedical research and investment. In America, 15 per cent of GDP is spent on health care, while only 6 per cent is spent on education. California alone is investing $3bn in stem-cell research, when there are more than three million illiterate adults in the state. Gene therapy and stem-cell research are the new elixirs, throughout the industrialised world.

Most of us are sceptical about visits to Lourdes, television evangelists, or even the reported miracles of the late John Paul II. But when it comes to rational scientific medicine, disbelief is often suspended. Disabled people are very familiar with this fascination with pioneering medical technologies. Researchers have been promising to make the crippled walk and the blind see for 50 years: the late Christopher Reeve was the most recent high-profile disabled person to have his expectations raised. But many disability rights activists would prefer to see immediate action to remedy inequality and social exclusion, having become frustrated with the promise of cures which are always "five years away".

In other words, it is risky to put our faith in the magic bullet. Social history proves that the major advances in health have always come from improvements to living conditions, not as the result of scientific drugs or treatment. Moreover, we live in an age where drugs are becoming less, not more, effective. Yes, you did read that last sentence correctly. Let me explain.

First, over-prescription and the rise of drug-resistant bacteria are steadily undermining the power of antibiotics. Meanwhile, tuberculosis is on the rise in the developing world, where 98 per cent of deaths caused by it occur. Similarly, antiviral therapies are currently effective against HIV, but it is inevitable that the virus will evolve into new and resistant strains.

Second, many pharmaceutical therapies are so toxic that they cause as many problems as they solve. For example, some of those treated successfully with chemotherapy for childhood cancers have been shown to be at raised risk of adult tumours.

Third, thanks to medical research, scientists now know more and more about less and less. With the rise of pharmacogenetics and personalised medicine, treatments are likely to be more specific and more effective, but they will benefit fewer people. This phenomenon also generates economic dilemmas: a 50 per cent cure rate for a disease variant that affects a tiny proportion of the population does not look attractive to global pharmaceutical companies, which claimit can cost $800m to bring a new drug to market.

Fourth, new preventative treatments such as statin and aspirin might be miracles, but they are not cures. Taking your daily pill will certainly reduce your risk, but it won't solve the problem or make you immune. For example, many people who take statins will still die from a heart attack.

Fifth, most common diseases are multifactorial: they are caused by complex interactions of genetic predisposition, diet, infection, lifestyle and working conditions. This makes it highly unlikely that a single pharmaceutical agent would be able to solve the problem.

Our contemporary obsession with the miracle cure obscures the simple fact that we all have to die of something. For example, over the past 30 years, the incidence of breast and lung cancer has doubled. The good news is that there are now many more effective treatments, and survival rates from cancer have increased: 10 years ago, the five-year survival rate for breast cancer was 73 per cent; by 2001, it had increased to 80 per cent. Now, two-thirds of women with breast cancer will survive for 20 years. Despite this success story, increasing numbers of people will be killed by cancer - because of their success in escaping death from other causes.

Death avoidance is a major industry. Less and less of us seem willing to go gently into that good night. Try Googling "life extension" and you will get 72 million hits. Most will be quacks in California promising to double your lifespan, but there are many reputable medical research programmes working towards helping you and me make a century. Some parts of America appear to believe that death is optional. But as my colleague, the Newcastle gerontologist Tom Kirkwood, argues, the aim of ageing medicine should be to add life to years, not years to life. If we worry about the increasing global population, we should remember that this is partly as a result of our survival into older age in the developed world, as well as of the developing world having more children.

Recent gains in life expectancy are associated with increases in morbidity. In other words, people in the industrialised countries may be living longer, but for many, our final 20 years will be blighted by dementia, macular degeneration, osteoarthritis - and increasingly costly medical treatment. Rather than aiming for immortality, the goal of medical research into ageing should be what gerontologists call "rectangularisation of the life curve". Or in the words of one of my friend's patients, "I want to live to 100 and then be shot by a jealous husband." People should worry less about when they are going to die, and place more emphasis on maintaining good health for a reasonable period, followed by a rapid death, not a slow decline.

What should our aspirations be, when it comes to medicine? What are the goals of health care? According to US bioethicist Dan Callahan, we just want more, more, more of it. No wonder we never decide that we have had enough. We are operating what he calls an "infinity model of progress". Callahan suggests that we need a debate on the limits to medicine. By accepting finitude and agreeing on sustainable healthcare, we might be able to consider what it means to live a good life and how we can improve the quality of life for more people. The problem is not medicine itself, it is the expectations that we place on our doctors, and the role we expect health care to play in our lives.

The real news story in medicine is the persistence of health inequality. If you are a male resident of Kensington and Chelsea, you can expect to live to 80, but if you are a man living in Shettleston, Glasgow, you are likely to be dead by 63. And social differentials in both life expectancy and infant mortality are actually getting worse. A cause and consequence of this situation is that the obsession with health and medicine is particularly associated with middle-class people, who expect to have choice and control over their lives and are unfamiliar with death. In contrast, many people in working-class communities have had experience of friends and relatives dying early. Expectations of medicine are lower and values such as coping and acceptance dominate. Premature mortality is even more acute on a global scale.

Ninety per cent of the world's pharmaceutical research is devoted to diseases which affect 10 per cent of the world's population. Every day 30,000 children die from preventable diseases. Factors such as malnutrition, infectious disease, lack of hygiene and war account for much of this toll.

Preventable death is largely associated with social factors. Between 1950 and 2050, 520 million people worldwide will die from smoking cigarettes, according to the World Bank and the World Health Organization. In Britain, less poverty, alcohol and tobacco and a better diet would do more for the nation's health than any high-technology medicine.

The pressing contemporary health disaster, for example, is the epidemic of type-two diabetes. Between 1994 and 2001, there was a 50 per cent increase in the prevalence of the disease in England and Wales. This is a worldwide phenomenon, and according to a recent Danish study the increase is entirely attributable to the concurrent increase in body mass index: the two major risk factors for type-two diabetes are obesity and lack of exercise. Faced with this health emergency, there are two possible solutions. Either, we rely on scientists spending millions to research a cure based on high-tech drugs or stem cells, or we all eat less and move more. So we should resolve to be less dependent on medical miracles, and take more responsibility for our own health? Sounds like a new year's resolution worth keeping.

Tom Shakespeare is a sociologist at the Policy, Ethics and Life Sciences Research Institute at the University of Newcastle