A major study is planned to see if simply taking vitamins can stave off Alzheimer’s disease.
The trial, involving around 1,000 older people in the UK, builds on previous findings that B vitamins can help prevent brain shrinkage with age.
Participants will be given carefully measured doses of vitamin B12, B6 and folic acid.
The aim is to find out whether boosting levels of the vitamins can delay the onset of Alzheimer’s or other forms of dementia.
A year ago the same team showed that taking the vitamin B combination reduced brain atrophy, or shrinkage, by 30% in 266 people aged 70 and over.
All those taking part in the two-year study had mild cognitive impairment (MCI), a pre-dementia condition characterised by poor memory.
As well as slowing brain shrinkage, the vitamins appeared to sharpen up episodic memory, the ability to recall specific past events in time and place.
The effects were linked to homocysteine, a protein molecule in the blood that is known to damage the lining of blood vessels and binds to neurons.
Homocysteine is raised when B vitamins are deficient and is also associated with dementia.
People with greater homocysteine levels experience more brain shrinkage in old age.
Better results in the original trial were seen in patients who started out with higher levels of the molecule. In memory tests, those treated with B vitamins were 69% more likely to remember words from a list than those who were untreated.
Now the researchers want to answer a bigger question: can reducing homocysteine with B vitamins actually prevent dementia?
Dr Celeste de Jager, from Oxford University, said: “We’re hoping to get around 1,000 people. It will be over two years, and the cognitive and clinical outcomes will be the main outcomes rather than the brain atrophy.”
The trial will use a “dementia scale” that provides a score for thinking ability, or cognition.
People with a mild cognitive impairment typically score around 0.5 on the scale.
“If we could keep people to 0.5 or get them back to zero, that’s what we would be aiming at,” said Dr de Jager.
She outlined the research plans today at the British Science Festival taking place at the University of Bradford.
Dr de Jager stressed that she was using medicinal doses of B vitamins higher than those found in standard health store supplements.
In the earlier trial, patients were given daily 0.5mg doses of vitamin B12, 20mg of B6, and 0.8mg of folic acid.
Older people who ate little protein risked not getting enough B12, which is mostly found in meat and fish, said Dr de Jager.
Eating few green vegetables could lead to a deficiency of folic acid.
Dr de Jager’s work has proved controversial, since other studies have failed to show similar benefits from taking B vitamins.
But she suggested this may be because they had looked at the wrong group of subjects.
“I think there’s a bit of scepticism against a vitamin being a treatment for Alzheimer’s disease,” said Dr de Jager. “There are other studies that haven’t been successful. We think ours was successful because we started at an early stage of memory loss rather than people with full-blown Alzheimer’s disease.
“We need more research to show that we can actually delay decline to dementia.”
More than 800,000 people in the UK have dementia, with around 60% suffering from Alzheimer’s.