New research from the University of Exeter, UK, has demonstrated that regular consumption of concentrated blueberry juice improves brain function in healthy older adults.
In the study, older adults who drank concentrated blueberry juice every day showed improvements in cognitive function, blood flow to the brain and activation of the brain while carrying out cognitive tests. There was also evidence suggesting improvement in working memory.
“Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties,” explained lead author Dr. Joanna Bowtell, Head of Sport and Health Sciences at the University of Exeter, and colleagues.
“High flavonoid intakes attenuate age-related cognitive decline, but data from human intervention studies are sparse.”
The researchers investigated whether 12 weeks of blueberry concentrate supplementation improved brain perfusion, task-related activation and cognitive function in healthy older adults.
Of the 26 adults in the study, 12 were given concentrated blueberry juice — providing the equivalent of 230 g of blueberries — once a day, while 14 received a placebo.
“Participants were randomized to consume either 30 ml blueberry concentrate (5 female, 7 male; age 67.5) or placebo (8 female, 6 male; age 69),” the authors explained.
“30 ml of blueberry concentrate was consumed once per day for 12 weeks and provided 387 mg anthocyanidins (34 mg malvidin, 108 mg cyanidin, 41 mg pelargonidin, 63 mg peonidin, 86 mg delphinidin, and 55 mg petunidin) and 25.5 g carbohydrate.”
“The placebo was a synthetic blackcurrant and apple cordial with sugar added to match blueberry energy content.”
Before and after the 12-week period, participants took a range of cognitive tests while an MRI scanner monitored their brain function and resting brain blood flow was measured.
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 study excluded anyone who said they consumed more than five portions of fruit and vegetables per day, and all participants were told to stick to their normal diet throughout.
“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,” Dr. Bowtell said.
“In this study we have shown that with just 12 weeks of consuming 30 ml of concentrated blueberry juice every day, brain blood flow, brain activation and some aspects of working memory were improved in a group of healthy older adults.”
Joanna L. Bowtell et al. Enhanced task related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation. Applied Physiology, Nutrition, and Metabolism, published online March 1, 2017; doi: 10.1139/apnm-2016-0550