Vitamin B 'may slow progress of dementia'

A large daily dose of vitamin B could help to delay the development of Alzheimer's disease, the most common cause of dementia.

Scientists at Oxford University studied the rate of brain shrinkage in 168 over-70s, all of whom had been diagnosed with mild cognitive impairment - a precursor to various forms of dementia.

Half of the participants were given a daily supplement containing high doses of folate, B6 and B12 for two years, while the remainder received a placebo (dummy pill).

Advanced magnetic resonance imaging (MRI) was used to study the degree of brain shrinkage, which occurs naturally in old age but is known to happen faster in people with mild cognitive impairment who subsequently develop Alzheimer's disease.

The research revealed that the rate of brain shrinkage was typically 30 per cent slower in people who took B vitamin supplements than in those who took the placebo.

In some people, the reduction in the rate of brain shrinkage was as high as 53 per cent.

Writing in the Public Library of Science (PLoS) One journal, the study authors suggested that the supplements could help to delay the development of Alzheimer's disease.

They are thought to work by controlling levels of the amino acid homocysteine in the blood, high levels of which are associated with an increased risk of Alzheimer's.

Co-lead researcher Professor David Smith, from Oxford University's department of pharmacology, commented: "It is our hope that this simple and safe treatment will delay the development of Alzheimer's disease in many people who suffer from mild memory problems."

The professor said that the results were "immensely promising", but noted that more trials are needed to confirm whether or not this particular combination of B vitamins can slow or even prevent the development of Alzheimer's.

"I wouldn't yet recommend that anyone getting a bit older and beginning to be worried about memory lapses should rush out and buy vitamin B supplements without seeing a doctor," he added.

Professor Clive Ballard, director of research at the Alzheimer's Society, agreed that more research is necessary, as previous studies looking at B vitamins had produced "very disappointing" results.

However, he conceded: "This is an interesting study which could change the lives of thousands of people at risk of dementia."