Vitamin B 'puts off Alzheimer's'
By Jane Hughes
Health correspondent, BBC News
Brain scan of a person with Alzheimer's
A new study suggests
high doses of B vitamins may halve the rate of brain shrinkage
in older people experiencing some of the warning signs of Alzheimer's
disease.
Brain shrinkage is one of the symptoms of mild cognitive impairment,
which often leads to dementia.
Researchers say this could be the first step towards finding a way
to delay the onset of Alzheimer's.
Experts said the findings were important but more research was needed.
The study, published in the journal Public Library of Science One,
looked at 168 elderly people experiencing levels of mental decline
known as mild cognitive impairment.
This condition, marked by mild memory lapses and language problems,
is beyond what can be explained by normal ageing and can be a precursor
to Alzheimer's and other forms of dementia.
Half of the volunteers were given a daily tablet containing levels
of the B vitamins folate, B6 and B12 well above the recommended daily
amount. The other half were given a placebo.
After two years, the rate at which their brains had shrunk was measured.
The average brain shrinks at a rate of 0.5% a year after the age of
60. The brains of those with mild cognitive impairment shrink twice
as fast. Alzheimer's patients have brain shrinkage of 2.5% a year.
The team, from the Oxford Project to investigate Memory and Ageing
(Optima), found that on average, in those taking vitamin supplements,
brain shrinkage slowed by 30%.
In some cases it slowed by more than 50%, making their brain atrophy
no worse than that of people without cognitive impairment.
'Protecting' the brain
Certain B vitamins - folic acid, vitamin B6 and B12 - control
levels of a substance known as homocysteine in the blood. High
levels of homocysteine are associated with faster brain shrinkage
and Alzheimer's disease.
"These vitamins are doing something to the brain structure
- they're protecting it, and that's very important because
we need to protect the brain to prevent Alzheimer's”
Professor David Smith
Oxford University
The study authors believe it was the B vitamins' effect on levels of homocysteine
that helped slow the rate of brain shrinkage.
The study author, Professor David Smith, said the results were more
significant than he had expected.
"It's a bigger effect than anyone could have predicted," he
said, "and it's telling us something biological.
"These vitamins are doing something to the brain structure -
they're protecting it, and that's very important because we need to
protect the brain to prevent Alzheimer's."
He said more research was now needed to see whether high doses of
B vitamins actually prevented the development of Alzheimer's in people
with mild cognitive impairment.
The Alzheimer's Research Trust, which co-funded the study, also called
for further investigation.
"These are very important results, with B vitamins now showing
a prospect of protecting some people from Alzheimer's in old age," said
chief executive Rebecca Wood.
"The strong findings must inspire an expanded trial to follow
people expected to develop Alzheimer's."
B vitamins are found naturally in many foods, including meat, fish,
eggs and green vegetables.
Experts are advising against taking higher than recommended levels
in the light of these findings.
Chris Kennard, chair of the Medical Research
Council's Neurosciences and Mental Health Board, said: "We must be cautious when recommending
supplements like vitamin B as there are separate health risks if taken
in too high doses.
"Further research is required before we can
recommend the supplement as a treatment for neurodegenerative diseases,
such as Alzheimer's."
Obtain supplies of B12 plus (with folic acid) from the Aloe Lady
