We now eat far too many omega 6 oils compared with omega 3s,
which may partly explain the increased prevalence of inflammatory
health problems affecting people in the Western world. So what are
omega 6s and omega 3s and how can we obtain a more optimum dietary
balance?
Omega 6s and omega 3s are types of polyunsaturated fatty acids
which are classified and named according to their chemical
structure. Quite simply, if their first double bond (where hydrogen
atoms are missing) is in position six on the molecule, they are
called omega 6s, and if their first double bond is in position
three, they are known as omega 3s.
The position of these double bonds plays a crucial role in how
your body processes them. The omega 6 fatty acids are converted
into a series of hormone-like substances (prostaglandins) that
promote inflammation, while the omega 3s are converted into a
series of prostaglandins that fight inflammation.
Your body cannot convert excess omega 6s to omega 3s, so
ideally, you need a balanced intake of both to discourage
inflammatory reactions in the body. In fact, humans evolved on a
Stone Age, hunter-gatherer diet of green plants, wild animals and
fish which contained equal amounts of omega 6s (from natural
vegetable oils) and omega 3s (from oily fish).
Our diet has changed enormously since Stone Age times and we now
eat at least 15 times more omega 6s than 3s, as our consumption of
meats, processed vegetable oils and fats has risen and our intake
of fresh oily fish and shellfish has decreased.
Unfortunately, our blueprint has not evolved to cope with these
changes as the rapidity of dietary evolution has far outstripped
any genetic evolution. Many experts now believe that our current,
excessive intake of omega 6 polyunsaturated fats (which promote
inflammation) and lack of omega 3s (which have an anti-inflammatory
action) is an underlying cause of the increased prevalence of
inflammatory conditions such as eczema, psoriasis, asthma,
arthritis and food intolerances. Inflammatory processes also
underlie the development of coronary heart disease and stroke.
Why we need more omega 3s
Most people would benefit from cutting back on their intake of
omega 6s and eating more omega 3s, which can improve your health
considerably.
That doesn’t mean cutting out the 6s altogether, however,
as both omega 6s and omega 3s have important functions in the body.
The omega 6 fatty acid known as GLA, for example (found in evening
primrose and starflower oils), is important for hormone balance and
skin health and helps to protect against depression. We just need
to balance our intake appropriately.
The original benefits of omega 3s were observed in the Inuit
people from Greenland, who have an unusually high intake of oily
fish and an unusually low incidence of coronary heart disease
(CHD). Fish is also eaten regularly by other healthy populations
with a low risk of CHD, such as those following Mediterranean and
Japanese-style diets.
Fish oils are beneficial for the heart and circulation as they
reduce levels of inflammatory chemicals, reduce blood viscosity and
platelet clumping, lower abnormal heart rhythms associated with
sudden death and have beneficial effects on cholesterol and
triglyceride balance. The protective effects of consuming fish oils
develop within four weeks of increasing consumption and continue to
improve so that, after two years, those on a high fish diet are
almost a third less likely to die from CHD than those eating very
little fish. Eating it two to four times a week can lower your risk
of a stroke by 27%, while eating fish five or more times a week can
reduce the risk of stroke by 52%.
Unfortunately, the Food Standards Agency in the UK suggests that
men, boys and women past child-bearing age (or who are not able or
intending to have further children) should only have up to four
portions of oily fish a week before the possible risks from sea
pollutants (mercury, dioxins, PCBs) might outweigh the known health
benefits. Girls and women who may become pregnant at some point in
their life should limit their intake of oily fish to between one
and two portions a week to obtain the known health benefits whilst
limiting any possible adverse effects of pollutants on children
they may have in the future. Pregnant and breast feeding women can
also eat one to two portions of oily fish a week (but should avoid
shark, marlin and swordfish and limit tuna intake).
The optimum daily dose of omega 3s must therefore come from
supplements, which are screened for pollutant levels and may be
taken daily. For those surviving a heart attack, omega 3 fish oil
supplements offer a 20% decrease in overall risk of death and a 30%
decrease in the risk of cardiovascular death.
Fish oils are also important for brain development and function
and for improving joint pain and stiffness.
Addressing the balance
Cut out excess omega 6s by consuming less: vegetable oils, meat,
margarines, convenience foods, fast foods, manufactured goods such
as cakes, sweets and pastries.
Consume more omega 3s via oily fish or supplements.
For vegetarians, non-fish sources of omega 3s include algae (and
vegetarian omega 3 supplements derived from algae), walnuts,
flaxseed and hempseed oils.
NB. Seek medical advice before taking fish oil supplements if
you have a blood-clotting disorder or are taking a blood thinning
drug such as warfarin (they may increase the tendency to
bleed).
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