A trial to see if vitamins can help prevent Alzheimer's is vital, say experts.
The incurable brain disease affects six million elderly people in the EU and the number is expected to double over the next 20 to 30 years.
Vitamins may help Alzheimer's patients
Vitamin supplements may be a cheap and effective method of preventing the disease and researchers are raising funds for a UK-wide trial to see if they are safe and effective.
Alzheimer's researcher Professor David Smith, at the University of Oxford, who is heading the trial effort, said: "It is absolutely vital to do this research.
"The UK has a head start in Alzheimer's research and the US can't do this trial because it already adds folic acid to all its flour."
This means all Americans already receive a vitamin supplement through the food they eat, so there is no way to compare with a supplement-free diet.
Recent research in the UK and US has hinted that low levels of folic acid and vitamin B12 in the body may contribute to Alzheimer's.
The reason for this is the discovery that a substance called homocysteine is found in high quantities in the blood of sufferers.
These higher levels are also found in normal people with slight cognitive impairments, such as problems drawing simple shapes.
These people are much more likely to go on to develop full-blown Alzheimer's.
Homocysteine is a by-product of an important chain of chemical reactions that activates enzymes in the body work.
Folic acid and vitamin B12 convert it back to a useful form.
If the body lacks these vitamins, homocysteine builds up.
Exactly how this damages the body is not yet known, but it has already been linked to a higher risk of heart disease.
Dr Andrew McCaddon, a GP in North Wales has been successfully improving the symptoms of patients with Alzheimer's by lowering their homocysteine levels with vitamin supplements and anti-oxidants.
The amount spent on Alzheimer's is woefully inadequate
Professor David Smith, University of Oxford
However he believes that prevention of Alzheimer's is the best way forward: "We must look at people before they get dementia," he said, "that's why the new trial is so important."
The proposed trial will involve 3,600 elderly people with "mild cognitive impairment".
Some will be given folic acid and vitamin B12 supplements, others dummy pills, and their progress tracked over five years.
One of the most important aspects of the trial will be to assess the safety of using these supplements.
"The great thing about homocysteine is we think the vitamin treatment is probably safe," said Professor Smith.
"However I definitely wouldn't advise the elderly to start taking folic acid until we have the results of this trial - there may be unknown risks such as cancer."
The trial is being considered for funding by the Alzheimer's Research Trust, but more money will be needed to run it.
"Homocysteine is certainly an important and interesting area for Alzheimer's," said a spokesperson for the charity.
She said the amount spent on researching Alzheimer's was pitifully low compared to other diseases such as cancer, which affects an equal number of people.
"The amount spent on Alzheimer's is woefully inadequate," agreed Professor Smith.
"It is a terrible disease that has devastating affects on the family and the economy."