Blueberries could protect the middle-aged from developing dementia.
A new study has found that patients aged between 50 and 65 with memory problems who took a blueberry powder supplement for 12 weeks performed better in mental tests.
The fruit contains high levels of micronutrients and antioxidants called anthocyanins. These give blueberries their colour and also protect against radiation exposure and infections.
Professor Robert Krikorian, from Cincinnati University in the US, said: "We had observed cognitive benefits in prior studies with older adults and thought they might be effective in younger individuals with insulin resistance.
"Alzheimer's disease, like all chronic diseases of ageing, develops over a period of many years beginning in midlife.
"These same properties that help blueberries survive also provide benefits such as reducing inflammation, improving metabolic function and enhancing energy production."