Daily vitamin pill could reduce dementia's effects by up to 50 per cent

Tests suggest vitamin B supplements can dramatically slow the onset of Alzheimer's and similar diseases

Scientists unveiled the latest weapon in the battle against Alzheimer's disease yesterday – a humble vitamin.

Researchers from the University of Oxford have found that taking tablets of three B vitamins every day slows the brain shrinkage that happens with age, causing early signs of dementia such as memory loss.

In a two-year trial, the vitamin supplement delayed the rate of brain atrophy by up to half in a group of elderly people, with a more than 30 per cent reduction overall. Cognitive tests show those with the least shrinkage perform best.

A vitamin pill that curbed the mental decline associated with ageing would have colossal implications. About 1.5 million people in the UK, 14 million in Europe and five million in the US have problems with memory, language or other mental functions known as Mild Cognitive Impairment (MCI), half of whom go on to develop Alzheimer's or another form of dementia within five years. Even a slight slowing of this process would have immense human and economic benefits. However, the researchers said it was too soon to recommend elderly people suffering memory lapses should take B vitamin supplements, until further studies had confirmed the benefits and risks.

Large doses of around 300 times the daily recommended intake of B12 and four times the recommended levels of folic acid were used in the trial. The researchers said this meant they acted like a pharmaceutical drug rather than a nutritional supplement and would require further safety tests. They are now seeking funding for another trial.

B vitamins are found in meat, whole grains, potatoes and Marmite. They promote cell growth and division, enhance the immune system and maintain healthy skin and bones.

Processed foods such as sugar and white flour contain lower levels of B vitamins and elderly people on a limited diet can become deficient. Low levels are common in Western populations. However, taking B vitamin supplements in large doses can be harmful. There are eight B vitamins, but only three were used in the study – B6, B12 and folic acid (B9).

The Oxford research, carried out in association with colleagues in Norway, involved 168 people with MCI, half of whom were given daily doses of vitamin B12, B6 and folic acid (B9).

After two years, MRI scans showed the brains of those who had taken the vitamins had shrunk less – by 0.76 per cent a year – than those given placebo (1.08 per cent) – a 31 per cent difference. In the quarter of elderly people who responded best, the reduction in the rate of shrinkage was 53 per cent.

Brain shrinkage is known to occur more rapidly in people with MCI or Alzheimer's and high levels of the amino acid homocysteine are linked to an increased risk of the conditions. The researchers believe that the B vitamins slowed the brain atrophy seen in MCI and Alzheimer's by reducing the levels of homocysteine. People with the highest levels of homocysteine in their blood benefited most.

Although the trial was not designed to measure thinking ability, the researchers found that individuals with the lowest rates of shrinkage had the highest mental test scores.

The findings are published in the journal PLoS [Public Library of Science] One.

Professor David Smith of the Department of Pharmacology, Oxford University, and co-leader of the trial, said: "This is a very striking, dramatic result. 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.

"These are immensely promising results but we do need to do more trials to conclude whether these particular B vitamins can slow or prevent development of Alzheimer's. So 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."

Professor Smith said the key question was whether MCI was a mild manifestation of the more extreme Alzheimer's disease. "Is this a continuum? Are we seeing a disease that begins a long time ago and gets worse and worse? I personally think so."

The long-term effects of taking big doses of the vitamins were not known, and there was some evidence that high folate intake could be linked to cancer, he said. However, asked if he would try the vitamin treatment if he was diagnosed with MCI he said: "Yes, no hesitation. I would take it."

Chris Kennard, chair of the Medical Research Council's Neurosciences and Mental Health Board which co-funded the study, said: "This trial brings us a step closer to unravelling the complex neurobiology of ageing and cognitive decline."

What is Dementia?

Dementia is a loss of cognitive ability caused by diseases such as Alzheimer's, which affects around 750,000 people in the UK – a figure expected to rise to 1.7 million by 2050. It causes problems with memory and the skills needed to carry out everyday activities, meaning that many sufferers are unable to care for themselves. The condition most commonly affects the over-65s, one in 20 of whom are sufferers. However, there are also believed to be around 16,000 people under that age with dementia.

It is thought that the cost to the UK economy of dealing with dementia will be £27bn a year by 2018.

Dementia usually worsens slowly over time and there is no cure. However, doctors can ease the severity of the symptoms and slow their onset using drugs and other treatments.

Depression also affects 20 to 30 per cent of people who have dementia, and about 20 per cent have anxiety.