Dietary Fats: Sources of Various Fatty Acids
What is Omega-3 and where does it come from?
Fats fall into four groups: Saturated, Monounsaturated, Polyunsaturated (PUFA) and Highly Unsaturated Fatty Acids (HUFA). PUFA and HUFA are the healthiest fats. They are found throughout the body as a principal component of the cell membranes.
Among the PUFAs, alpha linolenic acid (ALA) is found in green leafy vegetables,
flax, flaxseed oil, canola oil and nuts. It is classified as an Omega-3. Within
the body, ALA is used to make another group of compounds; the Omega-3 HUFAs.
These include Eicosapentaenoic Acid (EPA) and Docosahexaenoic acid (DHA).
Although both EPA and DPA can be made in the body from ALA, the conversion rate
is very low, requiring very high consumption of ALA to yield sufficient EPA and
DHA. As a result, the best way to get these HUFAs is directly ---- by consuming
fish, algae or fish oil, which themselves contain DHA and EPA.
Certain fish contain more HUFAs than others, generally the best sources are cold
water fish, particularly herring, mackerel, sardines and anchovies.
There is another family of PUFAs known as Omega-6. Omega-6s are present in
abundance in the North American diet in the form of vegetable oils such as corn
and soybean oil.
In contrast to PUFAs and HUFAs, most of the animal derived fats are classified as
saturated and can contribute to heart disease. To visualize the difference
between PUFAs and saturated fats, the PUFAs are liquid at room temperature, while
saturated fats are solid at room temperature (i.e. butter, lard, shortening).
The Benefits of Omega-3
Once consumed, the Omega 3s play a number of vital roles in the body. One of these
roles is that they are converted into hormone-like substances called “eicosanoids”.
From the Omega-3 family, EPA and DHA are the parent compounds forming eicosanoids. Among the Omega
6s, gamma linoleic acid (GLA) and arachidonic acid (AA) form eicosanoids. Eicosanoids are involved
in every aspect of the ways our bodies function. Among other things, they moderate our immune
system and blood pressure, our response to pain and our susceptibility to allergies and
inflammation.
The eicosanoids produced from Omega-3 are anti-inflammatory and have the opposite effects to those
produced from Omega-6, which are considered pro-inflammatory. By altering the balance of Omega-3
to Omega-6 in our diets we can change our eicosanoid production. If diets are high in Omega-6, more
pro-inflammatory eicosanoids are produced, increasing the risk of heart disease, arthritis, asthma,
allergies and other chronic inflammatory diseases. If you consume more Omega-3, then not only will
you produce more anti-inflammatory eicosanoids, but you will also displace some of the
pro-inflammatory compounds created by Omega-6.
As the above chart shows, Omega-6s produce mixed results in the body. In general the Omega-6s are
classified as highly pro-inflammatory, while, two of these compounds; GLA and CLA are primarily
beneficial.
Achieving the Right Balance
In North America we consume far more Omega-6 than Omega-3 due to the widespread use of vegetable
oils (corn and soy bean oil). Scientists have calculated that we consume anywhere from 10-30 times
as much Omega-6 as Omega-3, whereas, only one or two generations ago, the Western diet was close
to a 2:1 balance.
People who live in countries like Japan, Greenland, Iceland and Scandinavia have very low incidence
of heart disease, which has been largely associated with their diets. One of the most
distinguishing features of dietary comparisons is that these populations consume far more Omega-3
and far less Omega-6 than those in North America.
Omega-3 supplementation goes a long way towards addressing the current imbalance of Omega-3 to
Omega-6. In addition, by educating ourselves, by watching what we eat and by carefully reading
labels, we can reduce our consumption of Omega-6 and achieve an even healthier balance in our diet.