Older people with lower than average vitamin B12 levels were more than six times more likely to experience brain shrinkage, researchers concluded.
The University of Oxford study, published in the journal Neurology, tested the 107 apparently healthy volunteers over a five-year period.
Some studies suggest two out of five people are deficient in the vitamin. The problem is even more common among the elderly. The Oxford study looked at a group of people between 61 and 87, splitting it into thirds depending on the participants' vitamin B12 levels. Even the third with the lowest levels were still above a threshold used by some scientists to define vitamin B12 deficiency. However, they were still much more likely to show signs of brain shrinkage over the five-year period. Shrinkage has been strongly linked with a higher risk of developing dementia at a later stage.
The study suggests that eating more B12 through a diet rich in meat, fish, fortified cereals or milk as part of a balanced diet might help protect the brain. Liver and shellfish are particularly rich sources of B12.
"The best way to reduce your risk of developing dementia is to keep active, eat a balanced diet, don't smoke and visit your GP to get your blood pressure and cholesterol checked." says Dr Susanne Sorensen, from the Alzheimer's Society, UK.
