The role of uncoupling proteins could be fundamental to protecting against degenerative disease and ageing

Dr Martin Brand, Dunn Human Nutrition Unit, Cambridge

This damage in turn has been linked to the development of age-related conditions such as Alzheimer's disease, diabetes and certain cancers.

The Medical Research Council's Dunn Human Nutrition Unit in Cambridge has discovered body chemicals which appear able to protect cells against the harmful effects of free radicals produced within them.

The chemicals, called uncoupling proteins, help shift the free radicals away from sensitive areas of the cell to other areas where they can be safely dealt with.

Scientists believe that an undersupply of the proteins may make it difficult for the cell to rid itself of free radicals.

Possible therapy

They are hopeful that, in future, it may be possible to increase the supply with a treatment - and offer greater protection against free radicals.

Dr Martin Brand, from the unit, said: "The role of uncoupling proteins could be fundamental to protecting against degenerative disease and ageing.

"We hope that by understanding their role, we could find potential new ways to prevent or treat free radical linked diseases.

"For example, we might be able to decrease cellular ageing by using chemicals which switch these proteins on." The research was published in the journal Nature.

Limit calories

Free radicals have been blamed for tissue damage throughout the body - and patients told to eat a diet including plenty of fruit and vegetables to limit their impact.

The secrets of ageing have proved highly elusive in the past, with scientists able to come forward with few methods of increasing lifespan.

One suggestion is that a very limited calorific intake will extend life.

Other research in the journal Science in 2000 reported that a gene mutation in fruit flies which appeared to mimic the effects of calorific restriction had the effect of virtually doubling lifespan.