Alzheimer's linked to vitamins

Both vitamins are found in common types of food

People with low levels of the vitamins B12 or folate may have a higher risk of developing Alzheimer's disease, say researchers.

Scientists found that 46 out of 78 Alzheimer's patients they examined had low levels of both vitamins.

They believe a lack of the two vitamins may influence levels of chemicals that play a vital role in transmitting signals around the brain.

There is thus no justification at present to take extra amounts of these vitamins in the hope that they will prevent the development of dementia

Professor David Smith, Alzheimer's Research Trust

Alternatively, the deficiencies may increase levels of a chemical called homocysteine that is known to poison nerve cells.

Researcher Dr Hui-Xin Wang said: "In our study, we found that low levels of either of these two vitamins were related to an increased Alzheimer's disease risk.

"Monitoring B12 and folate levels is important in order to avoid unfavourable conditions, even for those elderly people who are quite healthy in terms of cognition."

Dr Wang said that researchers had recorded low vitamin levels in elderly people for more than 30 years.

Previous research has linked this to neurological or psychiatric disorders - but never to Alzheimer's disease.

Similar findings

Professor David Smith, of the Alzheimer's Research Trust, said the research confirmed previous studies which suggested a similar link.

"None of the published studies can establish whether or not the low levels of vitamins actually cause some cases of Alzheimer's disease.

"It will be necessary to carry out further research, including clinical trials of vitamin supplementation, in order to test this hypothesis.

"There is thus no justification at present to take extra amounts of these vitamins in the hope that they will prevent the development of dementia, unless of course indicated by a doctor."

Professor Smith said further research on the question was being undertaken in several countries, including the UK.

Vitamin B12 is naturally found in animal foods including fish, milk and milk products, eggs, meat, and poultry.

Leafy greens such as spinach and turnip greens, dry beans and peas, fortified cereals and grain products, and some fruits and vegetables are rich food sources of folate - a form of water-soluble vitamin B.

The research is published in Neurology, the scientific journal of the American Academy of Neurology.