Omega-3 fatty acid and omega-6 fatty acid are essential fatty acids that our bodies cannot manufacture. They have to be included in our diets for survival. They are crucial for many aspects of our health including brain function, maintenance of bone health and the reproductive system, regulation of metabolism, skin stimulation and hair growth.
Both omega-3 and omega-6 fatty acids are polyunsaturated fats, also known as PUFAs. They differ in structure such that the omega-3 fatty acid chain has its first (green circle) carbon double bond at position 3 closest to the methyl group (blue box) (Figure 1.). Omega-6 fatty acid chain has its 1st double bond at position 6 from the methyl group end (Figure 2).
Figure 1. omega-3 fatty acid
Figure 2. omega-6 fatty acid
If you are unsure what all this means please refer to the earlier article on the four types of dietary fats.
Function Of Omega-3 fatty Acid
Omega-3 fatty acid comes in different forms. The omega-3 fatty acid variants which are critical for our bodies are:
- ALA -alpha-linolenic acid… In our bodies, this acid turns int DHA and EPA but not very efficiently. The conversion is only about 5%. So it is important that we eat DHA and EPA fatty acids.
- DHA – docosahexanoic acid
- EPA – eicosapentaenoic acid
Both DHA and EPA fatty acids are necessary for the production of hormones that control cell growth including the metabolism of cell membranes, immune functions and clotting of blood.
In other words, we need them to:
- reduce and regulate inflammation
- control excessive clotting
- boost insulin response
- assist in the development of healthy cell membranes
- regulate prostaglandin production
Function Of Omega-6 Fatty Acids
Omega-6 fatty acids are also used to produce hormones. Unlike omega-3 fatty acid, these fatty acids function in an opposite way.
Their function is to:
- increase inflammation (essential for immune response)
- promote platelet aggregation (important for blood clotting)
- promote normal blood lipid profiles
- promote cell proliferation
There are many different types of omega-6 fatty acids. One of them, GLA (gamma-linolenic acid), found in several plant based oils including evening primrose oil, borage oil and black currant seed oil actually fights inflammation.
If you look at the functions of each of the fatty acids they seem to be “as if” in contradiction. They appear to have opposite effects. Omega-6 fatty acids seem to increase these biochemical processes, where as omega-3 fatty acids seem to decrease these processes.
Problems With Omega-6 Imbalance In Our Diets
Without delving deeper into the biochemistry, for optimum health we need both of these fatty acids. But as you can imagine, based on their functions, they need to be in balance.
The diet of our ancestors contained roughly 1 : 1 ratio of these fatty acids.
In our diets, beginning with the introduction of the first vegetable soybean oil in 1920s and subsequently other vegetable oils, the ratio of omega-6 to omega-3 fatty acids became completely out of whack. At the present time the ratio of omega-6 to omega-3 fatty acids in our diets is much greater than 20:1 and in many diets in our population it is as high as 40:1. In other words we are consuming roughly 20 to 40 times more omega-6 than omega-3 fatty acids.
This imbalance has its consequences. Many diseases have been on the rise since the onset of processed foods manufacturing and the introduction of various vegetable oils into our diet. We have been seeing a rise in:
- coronary heart disease
- different kinds of cancers
- neurodegenerative diseases
- autoimmune diseases
- Alzheimer disease
- and a host of other diseases
Scientists believe that balancing out the ratio between omega-6 and omega-3 fatty acids will relieve some of these conditions.
Even when you reduce your total fat intake and adhere to the daily recommended intake, eating too much of some fats can still cause you problems because of the omega-6 and omega-3 fatty acid dilemma. We need them for survival but if we eat too much of omega-6 it will harm us.
You need to reduce the intake of omega-6 fatty acids and increase omega 3 fatty acids. The problem is that omega-6 are very common and they are present in many of the usual cooking oils. On the other hand, omega-3’s are pretty rare. Below is a table I came across online that will give you some answers, especially related to some of the oils we have been using in cooking.
image from: gbhealthwatch.com
Most of the omega-3 from plant sources comes in the for of ALA and as I mentioned before, ALA fatty acid does not convert to DHA and EPA fatty acids efficiently. It only converts at about 5% Therefore it is important that we add foods containing these essential fats into our diets.
Best Sources Of Omega-3 fatty acids (DHA and EPA):
- fish roe
- fish oil
- krill oil
The American Heart Association recommends eating at least two servings of fish a week, especially fatty fish. Also, they recommend that pregnant women and children avoid eating fish that may contain higher levels of mercury. Those include shark, swordfish and king mackerel.
Basically, even when it comes to fat a healthy diet is one of a balance. The best example of a healthy diet is Mediterranean diet. This diet does not depend on the same vegetable oils as we use in our diets, because it does not include much fried foods and emphasizes a diet that is rich in omega-3 fatty acids, particularly fish. This diet is one of the healthiest diets to be found, especially if you want to correct your ratio of omega-3 fatty acids and omega 6 fatty acids.