Adults who have high levels of lutein are better able to recall skills and information they learnt many years ago, a new study found.
The protective compound can be found in a range of green leafy vegetables and helps to preserve 'crystallized intelligence'.
It is believed to accumulate in the brain, where it has a protective effect on the region responsible for memory.
Researchers from the University of Illinois tested 122 adults between the age of 65 and 75 on their crystallized intelligence.
Blood samples were also collected to determine levels of lutein and MRI scans were conducted to analyse brain structures.
They focused on parts of the temporal cortex, a brain region that other studies suggest plays a role in the preservation of crystallized intelligence.
They found participants with higher blood serum levels of lutein tended to do better on the tests.
While they also tended to have thicker grey matter in the brain region that crystallized intelligence can be found - the parahippocampal cortex.
Lead researcher Aron Barbey said: 'We can only hypothesize at this point how lutein in the diet affects brain structure.
'It may be that it plays an anti-inflammatory role or aids in cell-to-cell signaling.
'But our finding adds to the evidence suggesting that particular nutrients slow age-related declines in cognition by influencing specific features of brain aging.'
Previous research has found lutein also helps to ward off vision loss.
A Florida International University study found it helps to prevent age-related macular degeneration - the leading cause of blindness in the developed world.
While it is also believed that the compound helps to ward off wrinkles as people grow older by keeping the skin flexible and hydrated.
The new study was published in the journal Frontiers in Ageing Neuroscience.