The Omega wave
Fish oils are supposed to boost our brainpower. But do
the facts really stack up? We went in search of the evidence.
Elliot is nine years old. A year ago, he was falling behind in
his schoolwork, particularly reading – which he found a struggle. He
had little interest in studying and would crash on the sofa to watch
TV when he got home from school.
But over the past year, a dramatic change has taken place in
Elliot. He has soared through the Harry Potter books and now heads
to the library after the school bell has sounded.
Elliot has been taking part in a scientific study on more than
100 children from 12 Durham schools. The children were required to
take a course of capsules with their meals for the duration of six
months.
“His reading jumped 18 months [over the trial period]. He’s just
a lot more interested in everything. He’s even developed an interest
in classical music,” says Sheila, Elliot’s mother.
Problems vanished
Over the course of the year, Elliot's academic problems
disappeared.
Mark, 10, who is in the year above Elliot at Timothy Hackworth
School in Shildon, Durham, experienced similar changes.
“When I first heard about it, I didn’t think Mark had any
problems. He’d only been taking them a few weeks when I started to
notice changes. His handwriting became better and his teachers said
he was joining in more in class discussions,” says Mark’s mother
Christine.
“At home, he started asking loads of questions. It was quite hard
work for me.”
The capsules given to children in the trial contained oils high
in Omega 3 fats, which are found naturally in oily fish such as
mackerel, salmon and sardines and in some plant crops such as rape
seed.
Omega 3s and another group called Omega 6s belong to a family of
fats known as essential fatty acids. The right balance of these two
types of fatty acids is important for the healthy functioning of
many parts of the body.
Heart of the matter
Omega 3 fatty acids are known to help prevent heart disease and
they can improve the condition of some patients with depression and
bipolar disorder. But their effects on brainpower have not been
investigated in the same depth.
The Durham trial was conducted by Dr Alex Richardson, a senior
research fellow in physiology at Mansfield College, University of
Oxford and Madeleine Portwood, a special educational psychologist
for Durham Local Education Authority.
The results have not yet been published, but they are expected to
show a statistically significant improvement in school performance
in the group of children given Omega 3 supplements. This does not
mean that every child benefitted from the treatment – many did not.
But according to Portwood, about 40% of children showed some clear
improvement.
In the dark
The children were selected on the basis that they were not
fulfilling their potential at school, but their general ability was
normal. They were subjected to regular tests to measure their
co-ordination, concentration and academic ability.
The study followed an experimental method called a randomised
double-blind controlled trial. Half the children were given capsules
of Omega 3 fatty acids, and half given placebos. Neither the
children nor those evaluating their progress knew which group was
taking which treatment.
Richardson believes that conditions such as dyspraxia –
characterised by poor physical co-ordination – dyslexia and
attention deficit and hyperactivity disorder (ADHD) form a spectrum
of associated conditions with some of the same underlying causes.
“Clinically, there is about 50% overlap between dyspraxia and
dyslexia,” says Richardson, “and both show a similar overlap with
ADHD.”
The dramatic effects of Omega 3 fatty acids on the children in
the Durham trial may hinge on several functions of fatty acids in
the brain.
Relay race
Electrical signals travelling through the brain get passed from
one brain cell, or neuron, to the next – much like the baton handed
between runners in a relay race. In the changeover, a signal needs
to leave one brain cell at a point called the synapse and cross a
physical gap before entering the neighbouring neuron.
For signals to enter a neuron, they need to pass through the
walls that surround them. These walls, known as cell membranes,
consist almost entirely of fats. About 20% are essential fatty acids
like Omega 3s.
Embedded in brain cell membranes are structures called ion
channels that open to allow the flow of electrical signals into the
cell or close to prevent the flow. They perform this function by
changing their shape.
One theory is that a specific Omega 3 fatty acid called
Docosahexaenoic acid (DHA) makes the membrane that holds these
channels more elastic, making it easier for ion channels to change
shape.
If there is not enough DHA available, the membrane substitutes it
with a molecule called DPA (n-6), which cells regard as the next
best thing. This substitute is almost identical to DHA, but a tiny
difference in the molecular structure of DPA (n-6) makes it vastly
less flexible.
The substitution of DHA for a less flexible substitute may make
it harder for ion channels to change shape within the fatty
membrane, hindering their control over electrical impulses entering
the cell.
No substitute
This substitution may also affect structures called G-proteins
that sit on the inside of the cell membrane and are a vital link in
the transmission of signals between brain cells. G-proteins help
molecules on the outside of the membrane communicate with molecules
on the inside.
The substitution of DHA for DPA (n-6) can cause a one
thousand-fold reduction in the ability of G-proteins to perform this
function, according to Dr Joseph Hibbeln of the National Institute
of Alcohol Abuse and Alcoholism (NIAAA) in Bethesda, US.
This effect may be particularly important before birth; when
connections are being created in the brain of the developing foetus.
It is here in the womb that the replacement of DHA with its less
supple alternative may have its most far-reaching effects.
“A good analogy is if you’re building a new [road network] and
you don’t have the right type of concrete, you might choose an
inferior substitute,” says Hibbeln.
“You might choose to make inadequate roads. But if you have the
optimal fatty acid, it’s like having the optimal concrete – you make
the right roads in the right places first time round.
“If you get the right type of concrete later, you can rip things
up and re-lay the road, but it’s more expensive.”
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Omega 3s can improve brain function at the very
simplest level, by improving blood flow - Dr Alex
Richardson
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Under pressure
But even if you’re prepared for the effort and expense, the
benefits of repairing intrinsically flawed connections in the brain
may be limited. The clearest indication of this came in 2001, in a
study led by Dr Richard Weisinger of the University of Melbourne,
Australia.
Weisinger’s team showed that laboratory rats deprived of
essential fatty acids at specific stages in their development
developed high blood pressure that remained elevated for the rest of
their lives. The brain’s control over the autonomic nervous system
and cardiovascular system was permanently affected.
However, studies such as the Durham trial suggest that all is not
lost, and that boosting Omega 3 intake may still confer significant
benefits.
The Omega 3 fatty acid used in the Durham trial was
Eicosapentaenoic acid (EPA). It may play an equally crucial role in
brain function. EPA is found only at very low levels in the cell
membranes; it seems to have a functional, rather than a structural
role.
“It can improve brain function at the very simplest level, by
improving blood flow,” says Richardson.
EPA helps the body manufacture important, hormone-like substances
called eicosanoids. Some of these substances help improve blood flow
around the body. They also seem to have controlling effects on
hormones and the immune system, both of which are known to affect
brain function.
Western diets contain very little Omega 3 fatty acid.
Hydrogenation, the process used to give foods a long shelf life,
removes them. But certain people may break down Omega 3 fatty acids
faster than others. Some of the children who showed greatest
improvement in the Durham trial might fall into this category.
But there is disagreement over which Omega 3 fatty acid would
perform best as a treatment. US researchers such as Hibbeln tend to
favour DHA, while British researchers, of which Richardson is one,
mostly regard EPA as the best option.
But some quarters of the medical research community are deeply
sceptical about the usefulness of so-called complementary therapies
- the category of treatment in which fish oil supplements are often
lumped.
Professor Richard Olson, a developmental psychologist at the
University of Colorado, Boulder and an expert on the treatment of
dyslexia, urged caution over a ‘quick fix’ syndrome towards the
treatment of learning disorders.
“I haven’t read the research, but I have a slight feeling of
unease because in the field of dyslexia particularly, one quick fix
after another seems to pop up and then fall by the wayside,” says
Olson.
“I hope they’re right. I’m just sceptical of easy answers because
there have been various schemes in the past and parents [with
dyslexic children] go out and spend a lot of money on them. For many
children with dyslexia, improvement can only be achieved with a lot
of hard work,” he adds.
Clinical value?
Professor Maggie Snowling, a psychologist at the University of
York also warned about the use of Omega 3s as a treatment for
dyslexia.
“These studies tend to show statistically significant effects,
but it’s not clear if there are any clinical effects or real
improvements for the children involved.
"[Omega 3s] are not a treatment for dyslexia. They might have
some slight benefit on children with attention disorder, and some of
them might have dyslexia. But there are a lot of provisos,” says
Snowling.
While researchers have yet to fully resolve how the balance of
different Omega 3s affects brain function, one point on which they
agree is that studies into their effects need to be widened beyond
children.
“To my knowledge, there are no studies linking Omega 3s to
improvements in cognition or neuropsychological function in
otherwise healthy adults,” says Hibbeln.
Does he think this is a promising area for future research?
Hibbeln answers plainly: “Yes.”
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