Anti-oxidants are unlikely to prevent ageing, UCL study suggests

1 December 2008

Diets and beauty products which claim to have antioxidant properties are unlikely to prevent ageing, according to research funded by the Wellcome Trust. Researchers at the UCL Institute of Healthy Ageing say this is because a key fifty-year-old theory about the causes of ageing is wrong.

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‘Superoxide’ free radicals – oxygen molecules which have an imbalance of electrons to protons – are generated in the body through natural processes such as metabolism. These free radicals can cause oxidation in the body, analogous to rust when iron is exposed to oxygen. Biological systems, such as the human body, are usually able to restrict or repair this damage.

In 1956, Denham Harman proposed the theory that ageing is caused by an accumulation of molecular damage caused by ‘oxidative stress’, the action of reactive forms of oxygen, such as superoxide, on cells. This theory has dominated the field of ageing research for over fifty years. But now, a study published today (30 November) in the journal ‘Genes & Development’ suggests that this theory is probably incorrect and that superoxide is not a major cause of ageing.

“The fact is that we don't understand much about the fundamental mechanisms of ageing,” says Dr David Gems from UCL. “The free radical theory of ageing has filled a knowledge vacuum for over fifty years now, but it just doesn't stand up to the evidence.”

Dr Gems and colleagues at the UCL Institute of Healthy Ageing studied the action of key genes involved in removing superoxide from the bodies of the nematode worm C. elegans, a commonly-used model for research into ageing. By manipulating these genes, they were able to control the worm’s ability to ‘mop up’ surplus superoxide and limit potential damage caused by oxidation.

Contrary to the result predicted by the ‘free radical’ theory of ageing, the researchers found that the lifespan of the worm was relatively unaffected by its ability to tackle the surplus superoxide. The findings, combined with similar recent findings from the University of Texas using mice, imply that this theory is incorrect.

“One of the hallmarks of ageing is the accumulation of molecular damage, but what causes this damage?” says Dr Gems. “It’s clear that if superoxide is involved, it only plays a small part in the story. Oxidative damage is clearly not a universal, major driver of the ageing process. Other factors, such as chemical reactions involving sugars in our body, clearly play a role.”

Dr Gems believes the study suggests that anti-ageing products, that claim to have anti-oxidant properties, are unlikely to have any effect.

“A healthy, balanced diet is very important for reducing the risk of developing many diseases associated with old age, such as cancer, diabetes and osteoporosis,” he says. “But there is no clear evidence that dietary antioxidants can slow or prevent ageing. There is even less evidence to support the claims of most anti-ageing products.”

The research was welcomed by Dr Alan Schafer, Head of Molecular and Physiological Sciences at the Wellcome Trust.

“With increasing lifespan comes greater exposure and vulnerability to the ageing process,” comments Dr Schafer. “Research such as this points to how much we have to learn about ageing, and the importance of understanding the mechanisms behind this process. This new study will encourage researchers to explore new avenues in ageing research.”

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The UCL Institute of Healthy Ageing
The Institute of Healthy Ageing is an interdisciplinary centre of excellence for research on the biology of ageing and ageing-related diseases. Its goal is to improve the health and quality of life for older people, and its primary purpose is to bring together researchers working on the basic biology of ageing (biogerontology) with those working to understand the causes of ageing-related disease. A secondary aim of the Institute is to nurture broader collaborations across UCL between researchers working on the biological, social, economic and ‘built environment’-related aspects of ageing. Through its combined activities, it hopes to transform healthcare technology and the social conditions of the elderly to create a future society in which the lives of older people are healthy, meaningful and happy. The work of the Institute is funded by a variety of sources, including UCL itself, and the Wellcome Trust by means of a Strategic Award granted in 2007.

The Wellcome Trust
The Wellcome Trust is an independent charity funding research to improve human and animal health. Established in 1936, and with an endowment of around £15 billion, it is the UK's largest non-governmental source of funds for biomedical research, both in the UL and internationally.It spends over £600 million each year to support the brightest scientists with the best ideas, and supports public debate about biomedical research and its impact on health and wellbeing.

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