WE ALL know eating your greens is good for you.
Now a study has linked a pigment found in leafy greens to brain health and intelligence in older people.
New research from the University of Illinois has found a link between the nutrient lutein - found mainly in leafy greens, cruciferous vegetables such as broccoli and also egg yolks - and 'crystallized intelligence', the ability to use the skills and knowledge acquired throughout a person's life.
The study asked 122 healthy participants aged between 65 and 75 to solve problems and answer a standard test of crystallised intelligence, while also testing their blood for lutein levels. They were also given MRI tests on the brain.
The researchers found that participants with higher blood serum levels of lutein tended to do better on tests of crystallised intelligence.
Graduate student Marta Zamroziewicz, who led the study said with Illinois psychology professor Aron Barnbey, said lutein builds up in the brain, embedding in cell membranes, where it likely plays "a neuroprotective role".
Those with higher serum lutein levels also tended to have thicker grey matter in the parahippocampal cortex, a brain region that - like crystallised intelligence - is preserved in healthy ageing.
"Our analysis revealed that grey matter volume of the parahippocampal cortex on the right side of the brain accounts for the relationships between lutein and crystallised intelligence," said Professor Barbey.
"This offers the first clue as to which brain regions specifically play a role in the preservation of crystallised intelligence and how factors such as diet may contribute to that relationship."
Professor Barbey said while it wasn't clear yet how lutein in the diet affects brain structure, it may play an anti-inflammatory role or aid in cell-to-cell signalling.
"But our finding adds to the evidence suggesting that particular nutrients slow age-related declines in cognition by influencing specific features of brain ageing," he said.
The study is reported in the journal Frontiers in Aging Neuroscience.
