Older people are more prone to infections and cancers, including those that affect the skin, and scientists have proposed an explanation why this may be the case and how the risk could be reduced.

A team from University College London compared two groups of people – one under the age of 40 and the other over 70 – and found that contrary to what scientists previously believed older people do not have more defective white blood cells called T cells.

The researchers also conducted laboratory experiments which showed it is possible to make older skin reactivate the process that attract T cells.

“This indicates that, in principle, the defect is entirely reversible,” says Professor Arne Akbar from UCL, who led the study.

“Once we get to the bottom of exactly which part of the signal to T cells has gone wrong we might then be in a position to intervene to boost skin immunity in older people,” he adds.

In the meantime, nutritional supplements containing antioxidants such as vitamins C, E, zinc and beta carotene have been recommended by health practitioners as a way to improve the immune system.