Dietary guidelines : fats (omega-3 and omega-6)

Omega-3 fatty acids

Omega-3 fatty acids are polyunsaturated fatty acids (PUFA’s).  They have long chains of 18-22 carbon atoms with the first of double bonds beginning at the third carbon atom (counting from the methyl end). This means they are missing more than one hydrogen, and have more than one carbon double bond instead. Omega-3 means that one of the double bonds in the fat chain is at carbon number 3 in the backbone.

Omega-3 is present in the oils of seeds, grains, nuts, legumes and green vegetables. (Flax seed oil, walnuts, canola oil and chia seeds).

Also present in grasses and algaes which humans don’t eat.

Omega-3 is found in grass-fed animals, oily algae eating fish, free range poultry and oysters.

In the animals and fish it is more common in the brains, livers or eggs. 

Humans cannot synthetize fatty acids. In humans three types of omega-3 fatty acids are needed.  ALA, DHA and EPA. They are essential.  Which means they must be ingested. You can ingest the shorter chain ALA fatty acids and then make EPA and DHA acids from it.  Efficiency is about 5%. This conversion pathway competes with Omega-6 pathway. 

ALA has 18 carbon atoms and 3 double bonds.

DHA has a chain of 22 carbon atoms with 6 double bonds.

EPA has a chain of 22 carbon atoms with 5 double bonds.

Omega-6 fatty acids

Omega-6 fatty acids are liquid polyunsaturated fatty acids (PUFA’s). They have their first double bond at carbon number 6 instead of carbon number 3. Whereas there are 3 important omega-3 fatty acids for human health, there is only one essential omega-6 fatty acid: Linoleic Acid (LA).

There are a number of different omega-6 fatty acids. They have a chain of 18,20,22,24 carbon atoms. They have 3, 4, 5 or 6 double bonds.

Nutritionally omega-6 comes from animal fat (10/20% omega-6) and seed oils (50-80% omega-6).

Omega-3 and omega-6 fatty acids

Omega-3 fatty acids are largely anti-inflammatory (heal yourself). They are important in preventing chronic inflammation.

They are also part of stabilizing cardiac cell membranes and in the cell membranes of the brain and the retina.

Omega-6 fatty acids are essential for inflammation (defend oneself).

If you knock yourself omega-6 will help formation of bruise.  Omega-3 will help you get rid of the bruise. Your body needs to be able to do both.  The body needs to defend itself from attack by mounting an inflammatory response and then eliminate the inflammation.  

The ratio of omega-3 to omega-6

There is evidence that our distant ancestors ate diets with a ratio of roughly 1:1.

Our more recent ancestors may have had a diet of with a ratio of from 2:1 to 4:1.

Today the average western man has a diet with a ratio of from 20:1 to 30:1.