A group of Australian researchers think so, and they're putting their theory to the test.

Led by University of Wollongong nutritional epidemiologist Professor Karen Charlton, the world-first research project will involve incorporating purple-red foods like blueberries and cherries into the diet of people at risk of dementia.

Foods with a deep red, purple or blue colour contain anthocyanins, a bioactive compound with strong anti-inflammatory and antioxidant properties, Professor Charlton said.

"Our work has been focusing on how these can have an effect on the brain," she said.

"Fifty million people live with dementia [worldwide], and that's expected to triple over the next 30 years,"

"About half a million [people] in Australia have dementia, so it's an important area to be working in."

Professor Charlton has been exploring the properties of purple foods for 12 years, since meeting the late researcher Jim Joseph at the University of Wollongong.

Mr Joseph's research had found blueberry extract was able to improve memory in aged rats.

"If you put the rats in a water maze and ask them to swim around, the rats that were cognitively impaired couldn't remember where the platform was," she said.

"When he gave them a blueberry extract, they performed very similarly to the young rats."

Professor Charlton took this concept to human trials, giving cherry juice to a group of 49 people with Alzheimer's Disease, and found significant improvements in the group's auditory and verbal learning.

With funding from the Dementia Centre for Research Collaboration, Professor Charlton is now adapting the concept on a larger scale in a world-first 'purple diet' study.

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The research team led by UOW and the Illawarra Health and Medical Research Institute (IHMRI) will recruit 150 people with mild cognitive impairment, with some to trial a purple diet and others to supplement their normal diet with a freeze-dried blackcurrant powder.

Professor Charlton hopes the research may make a difference in understanding how diet can affect our cognitive abilities.

"When you get to the point of dementia that impairs daily living, that is a disease state; we're trying to prevent that."

The researchers are currently searching for people aged 65 years and over with observed memory complaints to participate in the study based out of Sydney and Wollongong.