There are many articles regarding the benefits of Omega 3
fatty acids toward promoting and maintaining good health. It is referred to as “essential”
Omega 3 fatty acid because it requires to be ingested and cannot be
manufactured through our body’s biological processes.
The three types of omega-3 fatty acids that provide benefit
to our bodies these are:-
- ALA (α-linolenic acid) from plant oils
- EPA (eicosapentaenoic acid) from fish oils
- DHA (docosahexaenoic acid) from fish oils
The benefits of Omega 3 fatty acids include promoting the health
of the brain; the heart and eyes and reduction of cellular inflammation.
Excessive cellular inflammation can lead to many diseases and conditions, such
as heart disease, arthritis and certain types of cancers.
ALA
ALA is a short chain fatty acid, formed with 18 Carbon atoms.
The "direct" physiological of ALA are largely not proven and considered much less than EPA or DHA, where the benefits are more
established and proven. The main use by the body of ALA is as a source of
energy and a building block for DHA and EPA.
The body can use ALA to manufacture EPA and AHA. However,
the conversion is quite inefficient with only 6% converted to EPA and 4% to DHA.
The conversion is further reduced in people eating a diet rich Omega 6 fatty
acids, which is the case for the standard western diet. Can adults adequately convert ALA to DHA & EPA
Typical foods high in Omega 6 are, vegetable oils, margarine,
walnuts, pine nuts…. The list goes on and there are too many to list here. Omega
6 is much more prevalent in our typical foods than Omega 3 and if we want to
maintain good health we need to be vigilant and consume a sufficient and correct
amount of Omega 3.
EPA and DHA
EPA are DHA are long chain fatty acids and formed with 20 and
22 Carbon atoms respectively.
There are many articles available describing the
benefits of EPA and DHA and which benefit is derived from either. Those
articles and discussions whilst interesting are too in depth and detailed for
me to discuss here. However, what does seem
clear is that significant health benefits will be achieved if we ensure we ingest sufficient amounts of both EPA and DHA.
The key benefits of DHA and EPA include:-
- Reduction of cellular inflammation (caused by excessive amounts of Omega 6) and associated conditions;
- Reduction in LDL bad cholesterol;
- Increased HDL good cholesterol
- and reduction of Triglycerides fats in the blood.
Recommended Daily Intake
Various organizations provide advice on the amount of EPA
and DHA people should consume for the health benefits to be realized. These reference values vary
and some reference overall Omega 3 not differentiating between ALA, EPA and
DHA. For different groups of people with different health conditions and needs there is
also different recommendations.
The reference amounts of DHA/EPA vary between 500mg/day
to 1000mg/day between organizations.
The Food and Drug Administration have indicated that up to
3000mg/day of DHA/EPA is considered safe. It is also noted that many Japanese
may typically consume 700 to 1200 mg/day without any adverse consequence to
health and well documented lower incidence of heart disease and lower obesity.
Omega 3 Safety
In the last few years there have been various press reports that high levels Omega 3 are
related to higher incidence of prostate cancer. However, medical experts
have discredited these reports and pointed out errors in the conclusions. It is
worth noting that historically, prostate cancer rates a high amount of DHA/EPA
is consumed is lower than in western countries.
DHA/EPA Content of Different Foods
Food
|
DHA + EHA mg/100g
|
Food Amount (g) /Week
|
Salmon
|
2150
|
163 – 326
|
Herring
|
2000
|
175 – 350
|
Mackerel
|
1800
|
194 – 389
|
Anchovy
|
1450
|
241 – 283
|
Trout
|
950
|
368 – 737
|
Mussels
|
800
|
438 – 875
|
Oysters
|
450
|
778 – 1,556
|
Crab
|
400
|
875 – 1,750
|
Tuna
|
300
|
1,167 – 2,333
|
Snapper
|
300
|
1,167 – 2,333
|
Shrimp
|
300
|
1,167 – 2,333
|
Octopus
|
300
|
1,167 – 2,333
|
Haddock
|
200
|
1,750 – 3500
|
Cod
|
200
|
1,750 – 3500
|
Scallop
|
200
|
1,750 – 3500
|
Amount/week is the amount of the food you should eat per
week to get 500mg/day DHA/EPA.
In addition to the above natural sources some foods are fortified
with Omega 3 such as eggs, where the chickens are fed flax seed or fish meal
causing some Omega 3 to be transferred to the yolk.
Generally, it is considered that the amount of Omega 3 in a
fortified egg is minimal compared to natural sources and this is more of a
gimmick that allows egg producers to sell eggs at higher prices. Some egg
companies boast of 150g /egg for DHA/EPA, which may be overstated. Notwithstanding,
you would need to eat between 4 and 8 eggs/day to achieve the nutritional requirements fro DHA/EPA.
DHA/EPA as Supplements
Ok you don’t like fish, so how do you get your DHA/EPA?
There are many supplements on the market that claim to provide the amounts DHA
and EPA required for health, including first oils, cod
liver oil and krill oil.
The main problem with fish oils such and cod liver oil is
that they are highly perishable and require to be processed and handled very
carefully. Therefore, you may be taking a fish oil supplement or cod liver oil
for no benefit as the DHA/EPA has oxidized. Furthermore, this can also have adverse health effects.
Krill oil on the other hand is not as perishable as fish oil
as the oil contains more oxidants. Therefore, if you are to choose to get your
DHA/EPA via a supplement you should chose Krill oil. Krill oil versus fish oil
Vegetable Based Sources for EPA/DHA
Omega 3, ALA (α-linolenic acid) can be sourced through
vegetable oils. The highest concentrations are found in Chia with 17,600g/100g.
Based on a 10% conversion of ALA to DHA/EPA, 100g of Chia seeds would provide
176g of DHA/EPA. To meet the daily requirement with Chia seeds alone you would
need to consume 300g/day of the ground seeds. In addition you would need to monitor your Omega 6
intake carefully as this may inhibit the conversion of ALA to DHA/EPA. Seed oils are also highly perishable and similar to fish and cod liver oil should be avoided.
Summary
The most efficient and certain way to meet your long chain
Omega 3 requirements is by eating oily fish, the whole food.
This can be supplemented by adding
vegetable sources such as ground Chia seeds, however if you rely on seeds alone the quantities required to
be eaten are quite substantial.
If you wish to follow the supplement route consider Krill oil not fish oil or Cod liver oil, both of which are more likely to be oxidized and hence in effective or harmful.