The study data, presented at the Experimental Biology conference, suggests that eating berries could help to protect against the effects of ageing on brain functioning by increasing the clearance of damaging substances that accumulate in the brain as we age.
Led by researchers from the Tufts University and the University of Maryland, USA, the team evaluated the protective effects of berries on brain function, and specifically the ability of the brain to clear toxic accumulation, by feeding rats with a diet containing berries or no berries before subjecting them or a radiation model of aging.
Rats were fed a either a berry diet of blueberries and stawberries or a control diet for two months before the US-based team exposed them to irradiation - a model for accelerated aging. After the irradiation, some rats were evaluated at 36 hours and a second group at 30 days.
"After 30 days on the same berry diet, the rats experienced significant protection against radiation compared to control," said Dr Shibu Poulose, who worked on the study.
"We saw significant benefits to diets with both of the berries, and speculate it is due to the phytonutrients present."
The research team looked at neurochemical changes in the brain, in particular focusing on autophagy which can regulate the synthesis, degradation and recycling of cellular components. It is also the way in which the brain clears toxic accumulations, said the researchers.
"Most diseases of the brain such as Alzheimer's and Parkinson's have shown an increased amount of toxic protein," said Poulase. "Berries seem to promote autophagy, the brain's natural housekeeping mechanism, thereby reducing the toxic accumulation."
The research team confirmed that they are now conducting a human study in people aged between 60 and 75 years.
"We have a lot of animal work that suggests these compounds will protect the aged brain and reverse some of behavioral deficits," added Dr Barbara Shukitt-Hale, who is leading the new human study.
"We are hoping it will translate to human studies as well."