New York, Nov 22 (IANS): The same compounds that give plants and vegetables their vibrant colours might be able to boost brain functioning in older adults, new research suggests.

People get these compounds, known as carotenoids, from their diets, and two of them - lutein and zeaxanthin - have been shown in previous research to bolster eye and cognitive health in older adults.

What is not known is the neural mechanisms underlying the relationship between these compounds and cognition, said first author of the study Cutter Lindbergh from Franklin College of Arts and Sciences, University of Georgia in the US.

The researchers found that study participants with lower levels of these compounds had to rely on more brain power to complete memory-oriented tasks.

"If you can show that in fact there's a real mechanism behind this, then you could potentially use these nutritional supplements or changes in diet, and you could easily intervene and potentially improve cognition in older adults," corresponding author of the study L. Stephen Miller, Professor at University of Georgia said.

Some fruits and vegetables rich in carotenoids include carrots, apricots, mangoes and spinach, among others.

The researchers used fMRI technology, also known as functional MRI, to gauge the brain activity of more than 40 adults between 65 and 86 years old while they attempted to recall word pairings they were taught earlier.

The researchers then analyzed brain activity while the participants were in the machine, finding that those individuals with higher levels of lutein and zeaxanthin did not require as much brain activity to complete the task.

Participants with lower levels of lutein and zeaxanthin had to use more brain power and relied more heavily on different parts of the brain in order to remember the word pairings they were taught.

People with higher levels, on the other hand, were able to minimise the amount of brain activity necessary to complete the task. In other words, they were more "neurally efficient", according to the study published in the Journal of the International Neuropsychological Society.

The researchers said they will next study whether interventions like changing one's diet to include more vegetables containing the carotenoids or by adding nutritional supplements could boost individuals' neurocognitive performance.