Drinking concentrated blueberry juice improves brain function in seniors, says a study from the U.K.'s University of Exeter.

Healthy volunteers aged 65 to 77 who drank the concentrate daily showed improvements in cognitive function, blood flow to the brain, and activation of the brain while undergoing cognitive testing.

Blueberries are rich in flavonoids, which are both antioxidant and anti-inflammatory.

"Our cognitive function tends to decline as we get older, but previous research has shown that cognitive function is better preserved in healthy older adults with a diet rich in plant-based foods," said Dr. Joanna Bowtell.

"In this study we have shown that with just 12 weeks of consuming 30ml of concentrated blueberry juice every day, brain blood flow, brain activation and some aspects of working memory were improved in this group of healthy older adults." The concentrated juice was equivalent to one ounce, and was equal to about eight ounces of fresh blueberries.

Study participants were divided into two groups — about half were given concentrated blueberry juice while the other group received a placebo.

Before and after the 12-week period, volunteers took a range of cognitive tests as well as scans of their brains which measured brain function and resting brain flow.

Compared to the placebo group, those who took the blueberry supplement showed significant increases in brain activity in brain areas related to the tests.

The new study from the University of Exeter isn't the first study to associate blueberries with better brain function in older people. A 2016 study at the University of Cincinnati Academic Health Center found that it boosted the memories of those who already had mild cognitive impairment.

Researchers gave older adults either freeze-dried blueberry powder equivalent to a cup of fresh berries, or a placebo powder. After 16 weeks, those taking the blueberry powder showed an improvement in cognitive abilities when compared to those who took the placebo powder.

"The blueberry group demonstrated improved memory and improved access to words and concepts," said research leader Robert Krikorian, Ph.D. In addition, functional magnetic resonance imaging (fMRI) showed increased brain activity in those who took the blueberry powder.