The human brain may be protected from the ravages of age by a key vitamin found in meat, fish and milk, a study claims.
Oxford University scientists said vitamin B12 could help stop the brain shrinking - possibly preventing memory loss and dementia in older people.
A study of 107 people aged 61 to 87 found that those with lower vitamin B12 levels in their blood were six times more likely to experience brain shrinkage compared with those who had higher levels of the vitamin.
Anna Vogiatzoglou, from the university's department of physiology, anatomy and genetics, said: "Many factors that affect brain health are thought to be out of our control, but this study suggests that simply adjusting our diets to consume more vitamin B12 through eating meat, fish, fortified cereals or milk may be something we can easily adjust to prevent brain shrinkage and so perhaps save our memory."
In the study, published in the journal Neurology, brain volume loss was measured every year for five years.
The participants were given yearly physical examinations, MRI scans of their brains, tests to check their cognitive and memory skills, and blood tests to determine their levels of vitamin B12.
The results showed that the decrease in brain volume was greater among those with lower vitamin B12 levels.