Unless you’ve been living under a rock you should know, or at least have heard about, omega 3 fatty acids. If you haven’t its worth checking out our article on 5 Simple Food Choices for Long Term Health Results
I’m about to lay down all the knowledge you’ll ever need on Omega 3, 6 and 9.
Let’s start at the beginning
If you search ‘fatty acid’ in Wikipedia you will get the definition: ‘a fatty acid is a carboxylic acid with a long aliphatic chain, which is either saturated or unsaturated’. Yep, unless you’re a nerd like myself that probably made no sense, don’t worry I’ll translate, “A fatty acid is a chain of carbon, oxygen and hydrogen atoms with a carboxyl group (-COOH acid) on one end. The chain can be either saturated (rigid) or unsaturated (flexible)”. We can classify fatty acids based on the number of carbon atoms, whether they can accept more atoms, how flexible they are and where the first unsaturated bond appears in the chain (if it even has one).
Omega-3 and Omega-6 fatty acids are both poly-unsaturated (have more than on unsaturated bond) with the first double bond appearing on the 3rd and 6th carbon atom respectively. Both these fatty acids are considered essential because our body needs them to function but we cannot synthesise them (make them ourselves from other compounds), they must be obtained from our diet or though supplementing.
Omega 9 is a non-essential fatty acid (meaning our bodies can synthesise it) and will be discussed in a future article, so watch out for that.
NB: Omega 3 and 6 fatty acids are also called ω-3/ω-6 or n-3/n-6 fatty acids.
Omega-6 Fatty Acids: What you need to know
Omega-6 is not a single compound but rather an umbrella term for many fatty acids with an ‘n-6’ structure.
|Common name||Lipid name||Chemical name|
|Linoleic acid (LA)||18:2 (n−6)||all-cis-9,12-octadecadienoic acid|
|Gamma-linolenic acid (GLA)||18:3 (n−6)||all-cis-6,9,12-octadecatrienoic acid|
|Calendic acid||18:3 (n−6)||8E,10E,12Z-octadecatrienoic acid|
|Eicosadienoic acid||20:2 (n−6)||all-cis-11,14-eicosadienoic acid|
|Dihomo-gamma-linolenic acid (DGLA)||20:3 (n−6)||all-cis-8,11,14-eicosatrienoic acid|
|Arachidonic acid (AA)||20:4 (n−6)||all-cis-5,8,11,14-eicosatetraenoic acid|
|Docosadienoic acid||22:2 (n−6)||all-cis-13,16-docosadienoic acid|
|Adrenic acid||22:4 (n−6)||all-cis-7,10,13,16-docosatetraenoic acid|
|Docosapentaenoic acid||22:5 (n−6)||all-cis-4,7,10,13,16-docosapentaenoic acid|
|Tetracosatetraenoic acid||24:4 (n−6)||all-cis-9,12,15,18-tetracosatetraenoic acid|
|Tetracosapentaenoic acid||24:5 (n−6)||all-cis-6,9,12,15,18-tetracosapentaenoic acid|
Of these compounds, whilst they are all serve a purpose, the ones thought to be most important are Gamma-linolenic acid (GLA), Dihomo-gamma-linolenic acid (DGLA) and Arachidonic acid (AA).
Arachidonic acid (AA) is of particular importance because it responsible for the unfavourable inflammatory properties of the omega-6 family. Yep, this is the one causing all the bad press and unfortunately as you’ll read later it turns out we’re all likely getting too much of it.
Inflammation negatively affects our health and can exacerbate and even cause disease. In fact, most chronic diseases, such as cancer, diabetes, heart disease, eczema, arthritis and Alzheimer’s disease, are highly inflammatory. Because of this, the link between how we eat and disease is critical.
On the flip side Dihomo-gamma-linolenic acid (DGLA) has an anti-inflammatory property but is hard to come by within our diets. The best way to increase DGLA is to increase its precursor Gamma-linolenic acid (GLA) which can be found in evening primrose oil, borage oil and black currant seed oil.
Note: Whilst I have been speaking about the different omega-6 fatty acids individually, much like the omega-3 fatty acids, they are all intrinsically linked by a series of enzymes which converts one type to another. For example DGLA can be made via the elongation of GLA thanks to the elongase enzyme. The diagram below shows the cascade of events which can convert the most simple omega-6 acid, linoleic acid (LA), into GLA then to DGLA and eventually docosapentaenoic acid.
Omega-3 Fatty Acids: What you need to know
Omega-3 fatty acids are considered to be anti-inflammatory but the reality is they are probably either neutral or less inflammatory than their omega-6 counterparts. It is thought that early humans had a diet richer in omega-3 than our modern day equivalent and maybe this explains the increasing number of chronic inflammatory conditions, although that being said our ancient ancestors didn’t live as long either.
As with omega-6 fatty acids there is there are many different omega-3 or n-3 fatty acids of which the most common have been listed below:
|Common name||Lipid name||Chemical name|
|Hexadecatrienoic acid (HTA)||16:3 (n-3)||all–cis-7,10,13-hexadecatrienoic acid|
|α-Linolenic acid (ALA)||18:3 (n-3)||all–cis-9,12,15-octadecatrienoic acid|
|Stearidonic acid (SDA)||18:4 (n-3)||all–cis-6,9,12,15-octadecatetraenoic acid|
|Eicosatrienoic acid (ETE)||20:3 (n-3)||all–cis-11,14,17-eicosatrienoic acid|
|Eicosatetraenoic acid (ETA)||20:4 (n-3)||all–cis-8,11,14,17-eicosatetraenoic acid|
|Eicosapentaenoic acid (EPA)||20:5 (n-3)||all–cis-5,8,11,14,17-eicosapentaenoic acid|
|Heneicosapentaenoic acid (HPA)||21:5 (n-3)||all-cis-6,9,12,15,18-heneicosapentaenoic acid|
|Docosapentaenoic acid (DPA),
|22:5 (n-3)||all–cis-7,10,13,16,19-docosapentaenoic acid|
|Docosahexaenoic acid (DHA)||22:6 (n-3)||all–cis-4,7,10,13,16,19-docosahexaenoic acid|
|Tetracosapentaenoic acid||24:5 (n-3)||all–cis-9,12,15,18,21-tetracosapentaenoic acid|
|Tetracosahexaenoic acid (Nisinic acid)||24:6 (n-3)||all–cis-6,9,12,15,18,21-tetracosahexaenoic acid|
The most important of these n-3 fatty acids is α-Linolenic acid (ALA), Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA). Whilst we possess the ability to convert ALA into DHA after a series of steps involving different enzymes, the process of thought to be very inefficient (less than 5%), consequently it is better to consume these fatty acids (food or supplement) in the form we need. The diagram below shows the steps from ALA to DHA
EPA and DHA are thought to be responsible for much of the benefit of omega-3 fatty acids. Benefits include: reduced cholesterol, reduced blood pressure, antidepressant activity, visual and neurological development in infants, protective properties in Alzheimer’s disease and dementia, and so on. If you want to know more about the benefits of omega-3 we recommend you read ‘The Facts on Omega-3 Fatty Acids‘.
Omega 3 Vs Omega 6 – An Oily Showdown
Unfortunately because as mammals we lack the omega-3 desaturase enzyme so we cannot convert omega-6 fatty acids into omega-3 fatty acids. This means we must obtain both omega-3 and omega-6 essential fatty acids from our diet separately, there is no cross over. To make things more complicated the ratio of omega-3 to omega-6 matters because they both compete to use the same enzymes.
Early humans were thought to have a ratio of omega-3 to omega-6 of 1:1 but the gap, especially in the last century, has been increasing since. The average UK diet is thought to be 1:10 whereas our American cousins can be as high as 1:25! With the way we live now a 1:1 ratio is near impossible but achieving a ratio below 1:4 should be the aim, and countries like Japan (high fish consumption) do achieve this.
How are they in competition with each other?
For the sharpest tools in the shed you would have noticed that both groups use the same enzymes when converting from one form to another, consequently they compete with each other to access the same limited resource, enzymes. The diagram below demonstrates this more clearly
As a consequence of the competition the proportion of omega-3 to omega-6 in our diets is important to consider. An excess of omega-6 means more omega-6 will be processed in relation to omega-3 and thus an imbalance is created, a pro-inflammation imbalance. The same applies if there is an excess of omega-3 to omega-6, however this very unlikely due to the limited sources we have for good omega-3 fatty acids and the abundance of omega-6 sources.
Is your fatty acid intake contributing to chronic Inflammation?
The best sources of omega-3 is oily fish such as salmon, mackerel, herring and sardines which provide EPA ad DHA, the specific fatty acids thought to provide the benefits of omega-3’s. Plant sources are available such as walnuts, chia seeds, flaxseeds (and its oil) and canola oil but they are low in EPA and DHA, instead they have decent levels of ALA.
Remember we mentioned earlier that the conversion of ALA into EPA and DHA is not very efficient and for this reason vegans and vegetarians relying exclusively on these sources need to ensure they eat adequate amounts; that’s also why vegans and vegetarians are notorious for having low omega-3 levels. There is research being done as to whether vegans and vegetarians can process ALA with greater success but the results are not conclusive as of yet.
Omega-6’s on the other hand are easy to come by and used in many of your favourite processed and fast foods. Vegetable oils tend to be high in omega-6 fatty acids include: corn, sunflower, sesame, peanut, soybean and anything called just ‘vegetable oil’. Sunflower and corn oil are the most common oils used in cooking and for this reason you are more than likely getting enough omega-6, probably too much. Over the past century our consumption of these oils has skyrocketed thanks to convenience food and with it our ratio of omega-3 to omega-6. Maybe this goes part way to explain why we are getting more chronic inflammatory conditions like IBS, Crohn’s and dermatitis.
Omega-6 and Inflammation
We touched on this earlier but in case you have forgotten Arachidonic acid (AA) is the specific omega-6 thought to cause inflammation. The mechanism for this is shown below:
So whilst AA is not directly responsible for inflammation it is its conversion into prostaglandins which does, and the pharmaceutical industry know it. Prostaglandins are not only involved in inflammation but amongst other things, the mediation of pain. Non-steroidal anti-inflammatory drugs or NSAIDS act by inhibiting the conversion of AA to prostaglandins by blocking the COX enzymes involved in the conversion.
NSAIDs include aspirin, ibuprofen, naproxen and diclofenac (Voltarol)
So should I take an Omega 3-6-9 supplement?
If you’ve been paying attention you should already know the answer. No. Whilst it sound great to be supplementing with a complete omega source, maybe even one with the optimum ratio of 3:6:9 the reality is your getting enough of 6, and 9 is a non-essential (look out for my article about Omega-9 soon). I recommend supplementing with omega-3 because most of you just aren’t getting enough, alternatively increase the amount oily fish your consuming (wild caught fish is better because farmed fish are fed high protein pellets low in omega)
How much omega-3 to eat depends in large part on how much omega-6 you eat.
Remember the ratio of 3:6 is important so whilst increasing your omega-3 intake is recommended you should also aim to reduce the amount of omega-6’s your consuming. Reduce the use of vegetable oils and foods prepared with them, yes this includes a lot of the processed, fried and convenient foods we all love.
It’s also a good idea to switch from vegetable oil to something with low omega-6 such as extra virgin olive oil, coconut oil, macadamia nut oil or canola oil.
A large proportion of GLA (good omega-6) from evening primrose oil (EPO) is converted to the anti-inflammatory DGLA (another good omega-6) so if you’re taking an EPO supplement, you don’t need to cut it.
Well I feel I scienced the shit out of that one and maybe a bit too much. Far too many initials but the take home message is simple: more omega-3 and less omega-6.
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