These are known as Essential Fatty Acids (EFA) as they are
necessary for health, but our bodies don’t directly make them. They are essential as the building blocks for
hormones which control immune function, blood clotting, as well as being
embedded in cell membranes and allowing the cells to be flexible and thus
function at their best. EFA also support
the healthy functioning of your immune system, as well forming the membranes of
nerve cells in the brain to allow them to grow and function normally.
There are 3 types of EFA known as ALA, EPA and DHA; ALA is
converted to EPA in the body, and then onto DHA. Although ALA can be converted it does require
adequate levels of vitamins and minerals in the body, oestrogen (in women) and
good liver function (since the liver converts it), but broadly speaking we are
not very efficient at this conversion particularly as Western diets are higher
in animal fats which impacts the conversion of ALA.
Most ALA comes from plant sources such as flax seed,
walnuts, pecans, hazelnuts, kiwifruit and some meats and fish. The richest sources of EPA and DHA are in the
flesh of oily fish such as salmon, tuna and mackerel.
EPA and DHA are both omega-3 fatty acids and are preformed
and ready to be used in the body and therefore are the preferred form for us to eat. As
humans we have always been depend on the sea historically; indeed the Romans are
recorded as using dolphins to coral fish.
It is suggested that since the beginnings of life when the first living system
converted sun into electricity (sparking the evolution of the brain and nervous
system), DHA was involved. No molecule
has ever replaced this in over 600 million years.
Pregnancy
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In pregnancy and lactation, the baby uses a quarter of the
mother’s stored omega-3 to make the brain.
From puberty as girls bodies change and fat stores are laid down, omega-3
is stored in the fat cells in readiness for eventual pregnancy. This omega-3 is liberated and used during
pregnancy and lactation, as well as having an increased dietary need. This must be considered in subsequent
pregnancies and if possible stored supplies should be replenished before
pregnancy.
70% of the brain cells divide before the baby is born,
therefore although we can supplement after birth there is a limit on how much
change we can effect on the brain structure.
Having a good diet and supplementation during pregnancy is crucial.
Supplements
Supplements can only maintain the brain and cell function we
already have. There has been some research
into increasing omega-3 in ADHD, but the research trials have been small with
mixed results so there is no clear evidence at present. There is no published guidance for the amount
of omega-3 which should be consumed, so the best advice is to eat 1-2 servings
of oily fish a week.
What’s the difference between omega-3 and omega-6?
Both are important for health, yet the most important thing
we must be aware of is the ratio we consume them in our diets. Historically it is believed that the ratio of
omega-3 to omega-6 was 1:1 but it is now more likely to be 1:10 or even higher.
Why is this important?
This is really important since the enzymes which convert the omega-3 and
6 will use either EFA, but the results of the conversion of omega-3 are
anti-inflammatory and anti-thrombotic (prevent the formation of clots), whereas
the results of omega-6 conversion are pro-inflammatory and pro-thrombotic. It is
the ratio of these EFA’s which is crucial – we need to lower our intake of
omega-6 to bring about balance. Don’t think
you should avoid omega-6 as it is necessary for health, just aim to alter the
ratio of omega-3 to 6. Be aware that too
much omega-3 (3 servings a day) is also detrimental to health as it may raise risk
of haemorrhagic stroke.
It is suggested that this imbalance may explain the rise in
inflammatory conditions such as asthma, coronary heart disease, many forms of
cancer, autoimmune diseases and neurodegenerative diseases since these are
believed to stem from inflammation in the body.
Additionally it is known that chronic tissue inflammation is indicated
in the development of insulin resistance, therefore the anti-inflammatory
action of omega-3 is important to uphold insulin sensitivity. Furthermore there is also evidence which suggests
that this imbalance could be a factor in violent behaviour, obesity,
depression, hyperactivity and dyslexia.
Correcting this imbalance could be a step in taking back
control over your health – a step which is easy to take and can only improve
our health and that of our families.
References
The Medical Biochemist.
Available at: http://themedicalbiochemistrypage.org/omegafats.php
University of Maryland Medical Centre. Available at: http://www.umm.edu/altmed/articles/omega-3-000316.htm
How stuff works.
Available at: http://health.howstuffworks.com/wellness/food-nutrition/healthy-eating/5-foods-high-in-omega-3.htm
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