Drinking two glasses of milk a day could help protect against Alzheimer's disease.
Oxford University scientists believe that vitamin B12, which occurs in milk, can reduce the brain damage that leads to dementia.
They found that elderly patients with low levels of B12 suffered from twice the amount of brain shrinkage as those with higher levels.
Prof David Smith, whose team's findings are published in the American Journal of Clinical Nutrition, said: "There are 550 people who come down with dementia every day in the UK - it is a major epidemic.
"It is unlikely we are ever going to find ways of repairing that damage. We have to look at preventing it in the first place."
