Omega-3 Fatty Acids

Alpha linolenic acid (Omega-6)

by Catherine M. Haug, December 2007; updated April 2019 (image, right, from Scientific Psychic (5))

As described in Fats & FattyAcids, The Omega number refers to the position of the last double bond in the fatty acid chain, as counted backwards from the last carbon (at the opposite end from the carboxylic acid (COOH) end of the chain).  Thus an Omega-3 fat has a double bond 3 bonds back from the end of the chain, as in the image, above right.

Omega-3 Fatty Acids

What is the difference between Omega-3 and Omega-6 fats? Both are poly-unsaturated fats, and each category has essential and non-essential members. They differ by where the first double-bond (closest to the methyl-end of the chain) is located. Check out a “” article (15) for great detail and helpful info.

Structural differences:

The following diagrams are from article (15); (note: the right-hand end of each example is the methyl-end):

Omega-3 example: alpha-linoleic acid (ALA*) (15):

Difference Between Omega 3 and Omega 6 Fatty Acids

‘* NOTE: there are 2 ALAs: alpha linoleic acid (above diagram) and alpha lipoic acid which is neither an Omega-3 nor Omega-6, but still a valuable fatty-acid. See “Two Different ALAs” near bottom of page, just before the References section, for more about ALAs.

Omega-6 example: linoleic acid (LA) (15):

Key Difference - Omega 3 vs Omega 6 Fatty Acids

Food-Source differences:

Another difference between Omega-3 and Omega-6 fats, is the food sources of each:

Omega-3: “α-linolenic acid (ALA) is found in plant oils such as walnut, edible seeds, clary sage seed oil, algal oil, flaxseed oil, Sacha Inchi oil, Echium oil, and hemp oil. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are both commonly found in marine oils, marine algae, phytoplankton, fish oil (from cold-water fish, including: salmon, tuna, mackerel, herring, and cod livers) and also in krill, squid and egg oils.(15,_ )

, krill oil, egg oil, and squid oil.” (15)

Omega-3s are found in a wide range of food sources, including:

  • Flax seeds
  • Algae
  • Cold-water fish, including salmon, tuna, mackerel, herring, and cod liver
  • Whale and seal blubber

See also “The Best Supplemental Sources of Omega-3s,” below.

Omega-6: “Rich in palm, soybean, rapeseed, evening primrose flower, cereal, and sunflower oils.” (15)

See also “Supplementation”section of my Omega-6 article.

Common Omega-3 Fats

The most common Omega-3 Fats are: (7B)

  1. Linolenic Acid (LA) is not essential but still helpful;
  2. Alpha Linolenic Acid (ALA) [I call it ALA3]* is an essential Omega-3; 
  3. Eicosapentaenoic Acid (EPA) is not essential but still helpful;
  4. Docosahexanoic Acid (DHA) is not essential but still helpful.

‘* See “Two Different ALAs” near bottom of page, just before the References section. This includes what I call ALA1, which is Alpha Lipoic Acid (not an Omega-3 nor Omega-6). What I call ALA3 is an Omega-3 (hence the ‘3’ in my name for it). I wish the two different acids did not use the same name: ALA. It is very confusing.

Of these fats, only LA (and its other form ALA3) is considered essential, but it is the longer chain Omega-3s: EPA and DHA, that are important for human metabolism.  

While EPA and DHA can be made from ALA3, our bodies are not very efficient at this conversion (about 5 – 15%), so it is best to ensure you get all forms in your diet. 4 The most common food sources include deep water fish, krill oil, organ meats, and egg yolks from properly raised chickens1 ; also seal oil. 14 

Benefits of Omega-3 Fats

They provide many benefits, including (5)

  1. Improve heart health;
  2. Reduce hypertension (high blood pressure);
  3. Improve autoimmune diseases;
  4. Improve depression;
  5. Aid cancer prevention and support;

Omega-3 fatty acids are precursors to specific eicosanoids. Eicosanoids are important for intercellular signaling. (7D)

Effect of insufficient Omega-3s

Both Omega-3 and Omega-6 fats are abundant in the cell membranes, where they are precursors of important chemical messengers. A deficiency in either, results in the necessity of using more saturated fats (or even the harmful trans fats if present in the diet) to construct cell membranes. While saturated fats are important in cell membranes, too many of them result in two significant consequences:

  • reduced ability to communicate with other cells (via chemical messengers); and
  • cell membranes are less elastic, a situation that makes the heart muscle stiffer and less able to return to a resting state (5)

Insufficiencies weaken certain immune functions; for example, Omega-3s are important in “helping cells resist infection with the herpes family of viruses and other similar organisms. Viruses have to penetrate the cell walls to reach the nucleus in order to reproduce. A healthy cell wall resists penetration while a weak cell wall is vulnerable.” (4)

Trans-fats (chemically altered fats) are known to cause problems for the heart, specifically hardening of the arteries (5).

Omega-3/Omega-6 balance

Dietary balance between these two types of fats is very important for our health. Most scientists agree their levels should be 1:1 ratio. One reason why this is so important is their affect on inflammation of tissues. Those made from:

  • Most Omega-3 fats are anti-inflammatory – i.e., protective;
  • Most Omega-6 fats are inflammatory; however, GLA (Gamma Linolenic Acid) is  considered a “good” omega-6 fat, because its effects are anti-inflammatory, like the omega-3 fats. See Omega-6 Fatty Acids, for more about this.

Because most Americans eat a diet high in omega-6 fats (mostly from seed oils like soy, corn and canola used in processed foods, or in home-cooking), we tend to have more inflammation in our body tissues. Increasing omega-3 fat consumption, especially those present in fish, and decreasing omega-6 fat consumption will bring these fats into proper balance.

Essential Omega-3 fats

While most Omega-3 fats can be made by the body, the most important ones: EPA and DHA, are considered “essential,” because our bodies cannot make them. The best sources of these fats are wild-caught fish, krill and krill oil, fish oil (from wild fish), and cod liver oil (from wild cod).


The sources I take are Green Pastures Fermented Cod Liver Oil (from wild-caught cod) and Mercola’s Krill Oil (krill cannot be farmed so all krill oil is from wild krill). I also add freshly ground flax seeds to my morning smoothie. Note: all of these also provide Omega-6 fatty acids.

I also eat wild-caught salmon 1 -2 days a week, when in-season (late-spring to early fall), and wild-caught cod 1 – 2 days a week during the rest of the year. Other fish and/or seafood high in Omega-3 and Omega-6 fatty acids are crab, tuna, mussels and oysters. Wild-caught mackerel, sardines, anchovies, herring, catfish and trout are also high in Omega-3s.

The best supplemental sources of Omega-3 fats are:

  • Flax oil (ALA) (but on its own is not very helpful for humans (see text below about ALA)
  • Fish oil (EPA, DHA); however some supplemental sources are contaminated with other oils, so be sure to read the label
  • Fish liver oil (EPA, DHA, vitamins A and D), especially if  from livers of fermented fish (such as Green Pastures Fermented Liver Oil, which I take)
  • Krill oil (EPA, DHA) is the best fish oil because the fish cannot be farmed; this is the one I take

However, ALA (I call it ALA1), the omega-3 in flax and other plants, needs to be converted to EPA or DHA to be useful for humans. And while we do have enzymes that can make that conversion, it is complicated by feedback mechanisms, resulting in insufficient conversion. Therefore, it is important to include animal-based omega-3s in your diet (fish oil, fish liver oil, krill oil).

Enzyme supplements: It is important to remember that the body has difficulty digesting and absorbing any fats without help.  That is:

  • the enzyme lipase removes the fatty acids from the glycerol backbone;
  • an emulsifier mixes the water-phobic fat with the watery chyme (what digesting food is called), so that lipase can do its work.

Most whole-food sources provide both of these; for example, raw egg yolks contain lecithin as an emulsifier,  and active lipase (cooking destroys the lipase).  But with supplementation, these must be added.  While the pancreas can excrete lipase for this purpose, it is more efficient if the lipase is provided by the food.  

Lecithin, a combo of choline and myo-inositol, is an excellent dietary additive, because it not only emulsifies the fats during digestion, but also provides choline, which is essential for fat metabolism in the liver. I get lecithin from eggs and my sunflower lecithin supplement (iHerb NOW-02313).

The best way to take supplemental fats is to mix the fat with a bit of lecithin and water or apple juice, and stir in some powdered fungal lipase.  Or mix the fat with a raw (or lightly coddled) egg yolk in a smoothie.

Two Different ALAs

  • Alpha Linolenic Acid (I call it ALA3): This is an essential Omega-3 fatty acid. However, taking too much can cause issues. 
  • Alpha Lipoic Acid (I call it ALA1): This is not an Omega-3 fatty acid, but I discuss it here because of the confusion caused by two different ALAs. It is both fat- and water-soluble, and is an important anti-oxidant fatty acid.

ALA3: Dr. Al Sears, in a sales pitch for his Omega Rejuvenol supplement (sorry, I didn’t save a copy of his email), says that “ALA can harm the brain, leading to memory issues.”  He didn’t specify which ALA he meant, but per a later sales pitch article by him that discusses ALA3 (an Omega-3) vs DHA (an Omega-6), he meant Alpha Linolenic Acid, because Alpha Lipoic Acid does the opposite, as I discuss next. The following ALA3 image is from reference (5).

ALA1: Many sources (including research) state that Alpha Lipoic Acid (ALA1) can reduce age-related memory loss, or at least slow its progression (8, 9, 10a, 10b, 11). This might be due to its positive effects on insulin resistance and blood sugar metabolism. ALA1 boosts acetylcholine, a neurotransmitter tied to memory and overall brain function. … It is a promising weapon in the fight against neurodegenerative diseases like Alzheimer’s. (12) ALA1 image, below, is from reference (13).

Taking ALA1 with a meal decreases it bioavailability. So taking it on an empty stomach (1 hour before eating) is recommended. Recommended ALA dosage (12) for:

    • Cognitive benefits is 2- 600 mg per day.
    • Diabetic neuropathy is 800 mg per day divided into two doses.
    • Antioxidant benefits is 50 – 100 mg per day.

Nov ’21: I currently take 50 mg capsules of alpha lipoic acid (ALA1) 3-times daily, away from meals to improve its bioavailability: before breakfast, before dinner, and at bedtime (3 hours after dinner). Previously I took it with meals (breakfast, lunch and dinner).


  1. The Skinny on Fats by Sally Fallon and Mary G, Enig, PhD
  7. Wikipedia:
    2. (8)
  8. Medical News Today (2018):
  9. ALA For Memory: Research and Safety:
  10. NCBI (scientific studies):
    1. Potential Therapeutic Effects of Lipoic Acid on Memory Deficits Related to Aging and Neurodegeneration (2017):
    2. Effect of alpha-lipoic acid on memory, oxidation, and lifespan in SAMP8 mice (2012):
  11. Potential Therapeutic Effects of Lipoic Acid on Memory Deficits Related to Aging and Neurodegeneration:
  13. ALA1 image (alpha lipoic acid):
  14. Omega3 Seal Oil:
  16. Andrew Peloquin email (7/23/22); I’ve saved a pdf copy: HEALTH-NUTRITION / PODCASTS-ARTICLES > DHA-Omega-3_WrinklesPrevention_APeloquin_072322a.pdf

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