In parts 1 and 2 of facts about fat, we discussed the different types of fat, their benefits, and ideal food sources. We broke down the differences between saturated fats, monounsaturated fats, polyunsaturated fats, and trans fats.
Fats are a main energy source for the body. Consuming quality fats daily is essential for numerous body functions, such as brain function, healthy skin and hair, immune function, healthy digestion, body temperature regulation, and aiding in the absorption of fat-soluble vitamins A, D, E, and K.
In this article, we’ll break down polyunsaturated fats into its two main categories: omega-6 and omega-3 fatty acids.
Polyunsaturated fats play a structural and regulatory role in the body. They form cell membranes, regulate gene expression, and aid in cell function.
While we need both omega-3 and omega-6 fats, it’s important to maintain a healthy balance. Too much omega-6 and too little omega-3 causes inflammation in the body, which contributes to chronic disease.
There are 6 different omega-6 fats and 6 different omega-3 fats, and they are classified by the length of their chains. Essential fatty acids are the shortest chain polyunsaturated fats. They are considered essential because they are required by the body and cannot be produced by the body. They must be obtained from our diet.
There is one essential omega-6 fat and one essential omega-3 fat. Linoleic acid is the essential omega-6 and alpha-linolenic acid (ALA) is the essential omega-3.
Both of these fats are converted into longer chain versions in our bodies. The most important long chain omega-6 fat is arachidonic acid (ARA), and the most important long chain omega-3 fats are EPA and DHA.
While linoleic acid and ALA are considered essential, it’s really the longer chain derivatives (ARA, EPA, and DHA) that provide the health benefits.
Linoleic acid (LA) is found in small and moderate amounts in a variety of foods, such as fruits, vegetables, cereal grains, and meat. It’s found in higher amounts in nuts and poultry. LA is present in large amounts in industrial seed oils like soybean, corn, cottonseed, sunflower, and safflower oils.
Research has shown that moderate intake of LA from whole foods is unlikely to cause health problems when sufficient amounts of long chain omega-3’s (EPA and DHA) are consumed.
However, large amounts of LA, especially in the form of industrial seed oils, and small amounts of EPA and DHA will have a pro-inflammatory effect in the body and can contribute to chronic disease.
Arachidonic Acid (ARA) is produced in our bodies from linoleic acid. It’s also found in foods like chicken, eggs, beef, and pork.
ARA serves several functions. It is present in cell membranes, it aids cells in exchanging information, it relaxes the blood vessels, it is necessary for the growth and repair of skeletal muscle tissue, and it’s one of the most abundant fatty acids in the brain along with DHA.
Recent research suggests that ARA may have some important anti-inflammatory actions as well. It is needed to make a group of molecules called lipoxins, which trigger the release of anti-inflammatory compounds derived from EPA and DHA. Higher plasma levels of ARA, EPA, and DHA have been associated with lower levels of inflammatory markers.
When it comes to omega-6 fats, the important thing to remember is to get them from whole foods. Consume moderate amounts of LA in the form of avocados, nuts, and poultry. Avoid industrial seed oils as much as you can. Consume meat, poultry, and eggs for a good source of ARA.
Alpha-linolenic acid (ALA) is the essential omega-3 fat that is found in plant foods such as walnuts and flax seeds. While ALA is considered “essential”, it’s really 2 of the long-chain omega-3 fats, EPA and DHA, that provide the health benefits.
Many people believe that we can meet our omega-3 requirements by consuming ALA in the form of flax oil, walnuts, or flax seeds. While the body can convert some of the ALA to EPA and DHA, this process is very inefficient in most people.
On average, less than 5% of ALA gets converted into EPA, and less than 0.5% of ALA gets converted into DHA.
EPA and DHA
There is a wealth of evidence that suggests adequate intake of EPA and DHA are essential to our health. It’s clear that a deficiency in EPA and DHA causes systemic inflammation and has played a huge role in the epidemic of modern inflammatory disease.
A few benefits EPA and DHA are:
Modest consumption of EPA and DHA (200-500 mg/d) reduces deaths from heart disease by 35%
DHA is necessary for proper brain development and preservation of brain function.
Regular consumption of fish or fish oil reduces overall risk of death by 17%.
The best sources of EPA and DHA are wild-caught, cold water, fatty fish, such as salmon, mackerel, sardines, herring, anchovies, bass and shellfish, like oysters and mussels. Much smaller levels of EPA and DHA are found in grass-fed animals and wild game.
An ideal ratio of omega-6 fats to omega-3 fats is thought to be between 2:1 and 1:1. However, in our Standard American Diet, this ratio is closer to between 10:1 and 20:1, which leads to inflammation and chronic disease.
The best way to find a healthy balance between omega-6 and omega-3 fats is by reducing your intake of LA, primarily industrial seed oils, and increasing your consumption of EPA and DHA through wild-caught fish.
While getting your EPA and DHA from food sources is the best option, supplementing with a high quality fish oil for therapeutic purposes could be helpful short-term. I recommend using cod liver oil as it provides a moderate amount of EPA and DHA along with beneficial vitamins A and D.
The Paleo Cure, Chris Kresser