A study of mice has shown that a natural compound found in blueberries, tea, grapes, and cocoa has the potential to boost memory, and that its effects further increase when combined with regular exercise.

The compound pointed at by the researchers is epicatechin, one of a group of chemicals known as flavonols that has been shown previously to improve cardiovascular function in people and increase blood flow in the brain.

In the latest study, Dr. Henriette van Praag of the California based Salk Institute for Biological Studies and her colleagues found that the combination of exercise, and a diet with epicatechin promoted structural and functional changes in the dentate gyrus, a part of the brain involved in the formation of learning and memory.

Published in The Journal of Neuroscience, their findings suggest that a diet rich in flavonols may help reduce the incidence or severity of neurodegenerative disease or cognitive disorders related to ageing.

"This finding is an important advance because it identifies a single natural chemical with memory-enhancing effects, suggesting that it may be possible to optimize brain function by combining exercise and dietary supplementation," says Dr. Mark Mattson at the National Institute on Ageing.

The researchers compared mice who were fed a typical diet with those given a diet supplemented with epicatechin. Half the mice in each group were made to run on a wheel for two hours each day.

After a period of one month, the researchers trained mice to find a platform hidden in a pool of water. They noticed that mice who both exercised and ate the epicatechin diet remembered the location of the platform longer than the other mice.

Upon a study of the brains of these mice, the researchers observed a greater blood vessel growth in the dentate gyrus and a more mature nerve cells, an indication of enhanced ability of the cells to communicate.

The researchers further said that the combination of epicatechin and exercise had a beneficial effect on the expression of genes important for learning and memory, and decreased the activity of genes playing a role in inflammation and neurodegeneration.

They say that though sedentary mice fed epicatechin showed enhanced memory, blood vessel growth, and gene activity during the study, such benefits were even more evident in mice that also exercised.

"A logical next step will be to study the effects of epicatechin on memory and brain blood flow in aged animals, and then humans, combined with mild exercise, " says van Praag.