A new study has found that blueberries can potentially add Alzheimer's to the list of diseases that it can help fight, alongside the likes of heart disease and cancer.
The fruit, which is known for its antioxidant properties, can help combat the effects of what is an increasingly common form of dementia, according to researchers at the University of Cincinnati Academic Health Center in the US.
Presenting their work at the 251st National Meeting & Exposition of the American Chemical Society (ACS), the researchers demonstrated how they conducted two human studies to follow up on earlier clinical trials.
"Our new findings corroborate those of previous animal studies and preliminary human studies, adding further support to the notion that blueberries can have a real benefit in improving memory and cognitive function in some older adults," said Dr Robert Krikorian, leader of the research team, who explained that blueberries' beneficial effects could be due to flavonoids called anthocyanins, which have been shown to improve animals' cognition.
One study involved 47 adults aged 68 and older, who had mild cognitive impairment, a risk condition for Alzheimer's disease.
The researchers gave them either freeze-dried blueberry powder, which is equivalent to a cup of berries, or a placebo powder once a day for 16 weeks.
"There was improvement in cognitive performance and brain function in those who had the blueberry powder compared with those who took the placebo," noted Krikorian. "The blueberry group demonstrated improved memory and improved access to words and concepts." The team also conducted functional magnetic resonance imaging (fMRI), which showed increased brain activity in those who ingested the blueberry powder.
The second study included 94 people aged 62 to 80, who were divided into four groups. The participants didn't have objectively measured cognitive issues, but they subjectively felt their memories were declining. The groups received blueberry powder, fish oil, fish oil and powder or placebo.
"The results were not as robust as with the first study," Krikorian explained. "Cognition was somewhat better for those with powder or fish oil separately, but there was little improvement with memory." Also, fMRI results also were not as striking for those receiving blueberry powder. He says that the effect may have been smaller in this case because these participants had less severe issues when they entered the study.
Krikorian said the two studies indicated that blueberries may be more effective in treating patients with cognitive impairments, but may not show measurable benefit for those with minor memory issues or who have not yet developed cognitive problems.
In the future, the team plans to conduct a blueberry study with a younger group of people, aged 50 to 65. The group would include people at risk of developing Alzheimer's, such as those who are obese, have high blood pressure or high cholesterol. This work could help the researchers determine if blueberries could help prevent the onset of Alzheimer's symptoms.