The key to slowing down ageing could be found in blood iron levels, according to an international study of genes.

Scientists at the University of Edinburgh and the Max Planck Institute for Biology of Ageing in Germany used genetic data from more than one million people to discover why some age at different rates.

They found maintaining healthy levels of iron in the blood could be key to ageing better and living longer, and suggest the study could accelerate the development of drugs to reduce age-related diseases.

Dr Paul Timmers, from the Usher Institute at the university, said: “We are very excited by these findings as they strongly suggest that high levels of iron in the blood reduces our healthy years of life and keeping these levels in check could prevent age-related damage.

“We speculate that our findings on iron metabolism might also start to explain why very high levels of iron-rich red meat in the diet has been linked to age-related conditions such as heart disease.”

Biological ageing varies between people and drives the world’s most fatal diseases including heart disease, dementia and cancers.

Extremely high or low levels of blood iron are linked to age-related conditions such as Parkinson’s disease, liver disease and the body’s declining ability to fight infection in later life.

Dr Joris Deelen, from the German institute, added: “Our ultimate aim is to discover how ageing is regulated and find ways to increase health during ageing.

“The 10 regions of the genome we have discovered that are linked to lifespan, healthspan and longevity are all exciting candidates for further studies.”

The study was funded by the Medical Research Council and is published in the journal Nature Communications.