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Kunnen vitamines het ontstaan van Alzheimer
uitstellen?*
Een artikel uit de Times online waaruit blijkt dat in het
bijzonder B-vitamines en
foliumzuur dit inderdaad kunnen doen.
When John
Roberts’s wife was found to have Alzheimer’s disease five years ago, at
the age of 74, what amazed him was how little the doctors had to offer. “The
psychiatrist said that he was sorry and that I was going to have a problem,”
said Roberts, a county councillor in Wales. “‘Keep her happy,’ he said,
and that was all.”
This
prescription may sound inadequate in the face of a disease that may involve
not only a progressive memory loss but also confusion, depression, fits of
anger and the disintegration of personality. Conventional medicine can still
do little more than help with symptoms but in fact there is another approach,
as Roberts discovered, which sounds absurdly simple — take vitamins and
mineral supplements.
Almost
unnoticed by mainstream medicine, the evidence has been piling up over the
past few years that there is a strong link between the amount of an amino acid
called homocysteine in your blood and your chance of developing Alzheimer’s.
Apparently you can lower the level, along with your risk of contracting the
disease, simply by taking a combination of B vitamins, antioxidants and
minerals.
“Keeping
your homocysteine level low halves your risk of developing Alzheimer’s,”
says Teodoro Bottiglieri, a neuropharmacologist at the Baylor Institute of
Metabolic Disease in Dallas, Texas. Professor Bottiglieri is one of the
speakers at a conference taking place in London tomorrow and Monday (February
1 and 2) devoted to the emerging discipline of nutritional psychiatry.
Besides
discussing Alzheimer’s, researchers will also be talking about
schizophrenia, depression and eating disorders.
Much
of this research has been done in the face of official indifference and one of
the most dogged researchers on the homocysteine trail is another speaker, the
Welsh GP Andrew McCaddon. Running small studies from the University of Wales,
he’s been piecing the story together for the past decade. Several years ago
he showed that patients with Alzheimer’s have significantly raised levels of
homocysteine. Next he reported that the more homocysteine they had, the worse
their mental performance and then last year he reported that the worse their
“cognitive impairment” the less they had of an antioxidant called
glutathione.
That
finding looks particularly interesting in light of a report that came out only
this week from the Johns Hopkins Bloomberg School of Public Health in
Baltimore. It described a five-year study, involving 4,740 people over 65,
which found that those taking large doses of the antioxidant vitamins C and E
had between a 64 per cent and 78 per cent lower risk of developing the
disorder.
So
what is going on here? Conventionally, Alzheimer’s has been seen to involve
a rogue protein known as beta-amyloid that forms the deadly plaques and
“tangles” that destroy brain cells. What have B vitamins and antioxidants
to do with that? “In fact what is extraordinary is that B vitamins have been
excluded from the Alzheimer picture for so long,” says Bottiglieri.
“The
link between brain deterioration — memory loss, cognitive deficits,
depression, and personality breakdown — and B vitamin deficiency is standard
neurology text-book stuff. You get it with severe alcoholism, with some
genetic disorders that prevent B vitamins functioning properly and with
pernicious anaemia. The trouble is that there is a lot of money tied up in the
amyloid protein story.”
What
has changed matters is the development of a simple blood test to detect
homocysteine levels, so it can be used to check how well your B vitamins are
working. That’s because the body needs B vitamins to handle homocysteine,
which it normally turns into two very useful chemicals called glutathione and
the amino acid SAMe. This, in turn, is vital for manufacture of one of the
main neurotransmitters, acetylcholine. Alzheimer’s patients have very low
levels of SAMe Acetylcholine should ring bells because not only is it
essential for laying down memories, but it is almost always found at very low
levels in Alzheimer patients. In fact, when patients do get drugs they are
usually aimed at boosting acetylcholine levels by preventing it from being
broken down. Their drawback is that the drugs only slow the decline slightly
and can cause liver damage, nausea and vomiting.
On
the other hand, getting the homocysteine-to-acetylcholine pathway working
properly by adding B vitamins doesn’t seem to lead to these problems.
But
why do the antioxidants, such as vitamin C and E, make a difference? “One of
the effects of the amyloid plaques encroaching on the brain is a rise in the
production of free radicals, or oxidative stress,” explains McCaddon.
“This adds to the problem because they reduce the effectiveness of the B
vitamins in transforming homocysteine.” Antioxidants, such as vitamin C and
E “mop up” the damaging free radicals. It is detailed molecular-level
research such as this that is encouraging scientists to take the
vitamin-homocysteine-Alzheimer’s link seriously.
“We
have been giving people different vitamin levels and then taking blood and
spinal fluid to see what effects they have,” says Bottiglieri. “We even
have a mouse model that is genetically engineered to develop plaques and
tangles. We’ve found that if you feed it on a diet low in B vitamins, the
plaque becomes much more toxic and that the production of free radicals
increases.”
So
what does all this mean in practical terms? “What would be really useful is
if GPs stopped thinking about B vitamin deficiency in terms of anaemia,”
says McCaddon. “Problems with the pathway involved with homocysteine often
don’t show up as a deficiency. If they would measure homocysteine first and
then take steps to lower it that would make a big difference.”
Already
the American Psychiatric Association recommends vitamin E supplements for
Alzheimer’s patients but all the experts emphasise that there is still much
work needed to fill in all the details of the new picture. “We know that
raised homocysteine predicts cognitive decline,” says McCaddon. “What is
still lacking is evidence from trials that lowering it makes a difference.
It’ s reasonable to suppose it does, but we have to wait for the results of
a big trial under way in the States due out next year.”
Meanwhile
given that extra vitamins are unlikely to do harm, finding out your
homocysteine level would make sense. This is not a cure but it may well cut
your risk and it looks like a promising way to help with symptoms.
'I've
got my wife back'
John
Roberts first realised his wife’s increasing forgetfulness was a sign of
something more serious about five years ago when she went shopping and
couldn’t find her way home.
For
three years he watched helplessly as she gradually worsened. “She became
very confused. She thought I was a stranger and she’d always been calm but
now she was often angry and upset.”
He
became a member of the local Alzheimer’s society. “From what I saw of how
the other patients progressed, I knew it wasn’t long before she would have
to go into a home.” But then he went to see
Dr
Andrew McCaddon. “His approach was different from the psychiatrist. He did
some blood tests and then put her on folic acid (a B vitamin) and other
vitamins.
It took a while,
but within about six months there was a great improvement. She became calmer
and started sleeping properly. When we went out, she noticed where she was
going. Her recent memory is still not good but her underlying personality is
there again. We can sit and have tea and biscuits, watch TV and talk. I’ve
got my wife back.”