Dementia is three times more common in people whose blood is low in folates, a form of vitamin B particularly found in green vegetables, a study suggests.
The Journal of Neurology, Neurosurgery and Psychiatry study followed 518 South Korean pensioners for two years.
There is growing evidence linking levels of folates - or folic acid - and Alzheimer's disease, though deficiency could be a symptom of dementia.
The UK is currently considering adding the vitamin to bread and flour. This is primarily for the benefit of pregnant women and their unborn children, as folic acid has been proven to prevent spinal problems in the growing foetus, but research increasingly suggests it could also ward off dementia.
However, the exact relationship between folate deficiency and dementia remains unclear, as it could well be a symptom as much as a cause.
Source - BBC