Purple fruit, such as blueberries, and green tea could help the body to ward off diseases such as Alzheimer's, Parkinson's and multiple sclerosis, research suggests.
A report from the University of Manchester has indicated that many debilitating illnesses are partially caused by faulty iron compounds called hydroxyl radicals.
Brightly-coloured fruits and green tea can safely bind the iron, helping the body to make better use of vitamins.
"Much of modern biology has been concerned with the role of different genes in human disease," said Professor Douglas Kell of the University of Manchester.
"The importance of iron may have been missed because there is no gene for iron as such."
However, Dr Simon Ridley, head of research at the Alzheimer's Research Trust, cautioned that the report is only a theory and there is currently no proven link between iron and dementia.
It follows reports from BBC News that Kay Hamilton, the widow of Angus Alan Douglas-Hamilton, is fronting a £1.5 million appeal to place a specialist dementia nurse on every health board in Scotland.
Find out more about Alzheimer's disease care at Barchester homes.