Blueberries may protect ageing brains and help prevent Alzheimer's, new research appears to show.

The "superfruit" berries given in the form of a powder, were found to improve the thinking performance of 47 adults aged 68 and older who already had mild cognitive impairment, a risk factor for Alzheimer's, a science conference in California was told.

Lead researcher Dr Robert Krikorian, from the University of Cincinnati in the US, said: