Essential Long-Chain Fatty Acids

The Relevances of  Essential Fatty Acids

Fat is perhaps the most diverse class of dietary macronutrients in regards to nutritional value and physiological effects. Currently, most people understand the differences between the good (unsaturated fat), bad (saturated fat) and ugly (trans-fat) fats described in Fat Metabolism 101. We know that oils derived from animal fat are not good for our health due to their high levels of saturated fat and cholesterol, and that oils derived from plants are generally good for our health due to their unsaturated fat content. However, not all unsaturated fats are healthy. Many plant seed oils such as sunflower, peanut and corn oil are rich in inflammatory polyunsaturated fatty acids (PUFAs) and devoid of anti-inflammatory PUFAs. On the other hand, some plant seed oils such as canola and olive oil have balanced PUFAs and are considered healthier. Therefore, it is important to distinguish between the types of PUFAs in dietary oils for optimal health.


PUFAs are fatty acids that have two or more double bonds in each molecule. There are two types of PUFAs in dietary oil: omega-3 and omega-6, also known as ω-3 and ω-6. They are distinguished by the position of the first double bond. Omega-3 fatty acids have their first double bond at the third carbon atom from the methyl end of the carbon chain while omega-6 fatty acids have their first double bond at the sixth carbon atom from the methyl end (Fig.1).

Structural representation of ALA

Figure 1. Structural representation of ALA (ω-3) and LA (ω-6), two essential fatty acids and the most common PUFAs found in dietary oil. The red numbers represents the carbon atoms counting from the methyl end of the chain. The blue counts from the carboxyl end.

Omega 3 Essential Fats

This is a family of essential fatty acids that play important roles in the human body (1).

The most common omega-3 fatty acids in the human diet are ALA, EPA, and DHA while the most common omega-6 fatty acids are LA and AA (Table 1). The omega-3 fatty acid ALA and the omega-6 fatty acid LA are referred to as essential fatty acids because the body cannot synthesize them. Essential fatty acid deficiency can lead to dermatitis, stunted growth in infants and children, increased susceptibility to infection, and poor wound healing. In human cells all long-chain omega-3 fatty acids are synthesized from ALA and all long-chain omega-6 fatty acids are synthesized from LA.


Omega-3 ALA α-Linolenic acid C18 : 3 Oils: flaxseed, olive, canola
EPA Eicosapentaenoic acid C20 : 5 Fish oil, marine algae
DHA Docosahexaenoic acid C22 : 6 Fish oil, marine algae
Omega-6 LA Linoleic acid C18 : 2 Oils: corn, soybean,
sunflower, peanut
AA Arachidonic acid C20 : 4 Small amount in meat,
dairy products and eggs

Long-chain omega-3 fatty acids (EPA and DHA) provide many health benefits with regard to their cardiovascular disease prevention properties and anti-inflammatory effects. DHA is also directly involved in visual and neuronal cell development. Adequate amounts of omega-6 fatty acids are also beneficial to human health since many bioactive signaling molecules, especially ones involved in immune response and cardiomyocyte (muscle cells) contraction, are derived from them. However, omega-6 fatty acids tend to be over-supplied while omega-3 fatty acids are under-supplied in modern Western diets due to industrialized food oil production. This overwhelming intake of omega-6 leads to hyperimmune responses and interferes with the proper function of omega-3 fatty acids, causing detrimental effects associated with chronic cardiovascular diseases and inflammatory responses (Table 2).

We can not produce them on our own, so we must get them from the diet.

Omega-3 fatty acids are polyunsaturated, meaning that they have several double bonds in the chemical structure.

The three most important types are ALA (alpha-linolenic acid), DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid).

ALA is mainly found in plants, while DHA and EPA are mainly found in animal foods and algae.

Omega-3 fatty acids are needed for optimal function of the human body, and they may also provide numerous powerful health benefits (2).

Common foods that are high in omega-3 fatty acids include fatty fish, fish oils, flax seeds, chia seeds, flaxseed oil and walnuts, to name a few.

The “omega” naming convention has to do with the placement of the double bonds on the fatty acid chain.

Each fatty acid has a long chain of carbon atoms, with one carboxylic acid end (called alpha) and one methyl end (called omega).


The number 3 means that the first double bond of the fatty acid molecule is located 3 carbon atoms away from the “omega” end.

Conversely, the double bond in omega-6 fatty acids is located 6 carbon atoms away from the omega end.

BOTTOM LINE:The “omega” naming convention has to do with the placement of the double bond in the fatty acid molecule. Omega-3 fatty acids have the first double bond placed 3 carbon atoms away from the omega end.

The Three Types: ALA, EPA and DHA

There are three main types of omega-3 fatty acids: ALA, DHA and EPA.

ALA (alpha-linolenic acid)

Alpha-linolenic acid (ALA) is the most common omega-3 fatty acid in the diet. It is 18 carbons long (3).It is not active in the human body, and needs to be converted into the active forms, EPA and DHA.

However, this conversion process is inefficient. Only a small percentage of ALA is converted into the active forms (456).

ALA is found in flaxseeds, flaxseed oil, canola oil, chia seeds, walnutshemp seeds and soybeans, to name a few.

EPA (eicosapentaenoic acid)

Eicosapentaenoic acid is an omega-3 fatty acid that is 20 carbons long.It is mostly found in animal products, such as fatty fish and fish oil. However, some microalgae also contain EPA.

It has several functions in the human body. Part of it can be converted into DHA.

DHA (docosahexaenoic acid)

Docosahexaenoic acid (DHA) is the most important omega-3 fatty acid in the human body. It is 22 carbons long.It is a key structural component of the brain, the retina of the eyes and numerous important parts of the body (7).

Like EPA, it is mostly found in animal products like fatty fish and fish oil. Meat, eggs and dairyproducts from grass-fed animals also tend to contain significant amounts.

Vegetarians and vegans are often lacking in DHA, and should take microalgae supplements, which contain DHA (89).

BOTTOM LINE:There are three main omega-3 fatty acids in the diet: ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).

The Omega-6:Omega-3 Ratio

Omega-6 fatty acids also have important roles in the human body.

Their function is often similar to the function of omega-3 fatty acids.

Both are used to produce signalling molecules called eicosanoids, which have various roles related to inflammation, blood clotting and others (10).

Omega-3 fatty acids are anti-inflammatory, but eating too much omega-6 counteracts these beneficial effects.

For this reason, we need to consume these fatty acids in a certain balance for optimal health. This balance between omega-6 and omega-3 is often termed the omega-6:omega-3 ratio.

These days, most people are eating way too many omega-6 fats, and way too few omega-3s, so the ratio is currently skewed far towards the omega-6 side (11).

BOTTOM LINE:Omega-3 and omega-6 fatty acids are used to produce important signalling molecules called eicosanoids. Getting both types of fatty acids in a certain balance is considered important for optimal health.

What Omega-3 Fatty Acids Do

Omega-3 fatty acids, particularly DHA, play structural roles in the brain and retina of the eyes (7).

It is particularly important for pregnant women and breastfeeding mothers to get enough DHA.

It can affect the future health and intelligence of the baby (12).

Additionally, getting enough omega-3 fatty acids can have powerful health benefits for adults as well. This is especially true of the longer-chain forms, EPA and DHA.

Although evidence is mixed, studies have shown that omega-3 fatty acids can have protective effects against all sorts of diseases.

This includes breast cancer, depression, ADHD, as well as various inflammatory diseases (13141516).

At the end of the day, omega-3 fatty acids are important, and the modern diet is severely lacking in them.

If you don’t like fish, then consider taking a supplement. It is both cheap and effective.

An evidence-based nutrition article from our experts at Authority Nutrition.



Omega-3 fatty acids are essential fats that you must get from the diet.

These incredibly healthy fats have important benefits for your body and brain ( 1, 2).

However, most people who eat a standard Western diet are not eating enough omega-3 fats. Not even close ( 3, 4).

This is the ultimate beginner’s guide to omega-3 fatty acids.

What Are Omega-3 Fatty Acids?

Omega-3 fatty acids are a family of polyunsaturated fats that we must get from the diet. They are also called n-3 or ω-3 fatty acids.

They are termed essential fatty acids because they are needed for health, but the body can not produce them on its own like other fats.

The polyunsaturated part means that the fatty acids have several double bonds in their chemical structure. Omega-6 fatty acids are another type of polyunsaturated fat.

The “omega” naming convention has to do with the placement of the double bond on the fatty acid molecule. Omega-3s have the first double bond placed 3 carbon atoms away from the omega end.



Omega-3 fatty acids are polyunsaturated fats that your body needs, but can not produce on its own. For this reason, they are classified as essential fatty acids.

The 3 Main Types of Omega-3 Fats

There are many fatty acids that technically belong to the omega-3 family.

These three are the most important:

1. EPA (Eicosapentaenoic Acid)

EPA is a 20-carbon-long omega-3 fatty acid. It is primarily found in fatty fish, seafood and fish oil.

This fatty acid has many essential functions. Most importantly, it is used to form signalling molecules called eicosanoids. This can lead to reduced inflammation ( 5).

EPA has been found to be particularly effective against certain mental conditions, especially depression ( 6).

2. DHA (Docosahexaenoic Acid)

DHA is a 22-carbon-long omega-3 fatty acid. It is primarily found in fatty fish, seafood, fish oils and algae.

The main role of DHA is to serve as a structural component in cell membranes, particularly in nerve cells in the brain and eyes. It constitutes about 40% of polyunsaturated fats in the brain ( 7).

DHA is very important during pregnancy and breastfeeding. It is absolutely crucial for the nervous system during development, and breast milk contains significant amounts of DHA ( 8, 9, 10, 11).

3. ALA (Alpha-Linolenic Acid)

ALA is an 18-carbon-long omega-3 fatty acid. It is found in high-fat plant foods, especially flax seeds, chia seeds and walnuts.

Despite being the most common omega-3 fat in the diet, ALA is not very active in the body. It needs to be converted into EPA and DHA in order to become active ( 12).

Unfortunately, this process is highly inefficient in humans. Only about 5% gets converted into EPA, and as little as 0.5% get converted into DHA ( 13).

For this reason, ALA should never be relied on as the sole omega-3 source. Most of the ALA you eat will simply be used for energy.



There are three main types of omega-3 fats in the diet. EPA and DHA are found in seafood and fish, while ALA is mostly found in high-fat plant foods.

Health Benefits of Omega-3 Fatty Acids

Omega-3 fatty acids are among the most comprehensively studied nutrients on earth.

They have been shown to have powerful health benefits for various body systems.

•Blood triglycerides: Omega-3 supplements can lower blood triglycerides significantly ( 14, 15, 16).

•Cancer: Consuming foods high in omega-3 has been linked to a reduced risk of colon, prostate and breast cancer. However, not all studies agree ( 17, 18, 19, 20, 21, 22).

•Fatty liver: Taking omega-3 fatty acid supplements can help get rid of excess fat from the liver ( 23, 24).

•Depression and anxiety: Taking omega-3 supplements, such as fish oil, can help reduce symptoms of depression and anxiety ( 25, 26, 27, 28).

•Inflammation and pain: Omega-3s can reduce inflammation and symptoms of various autoimmune diseases, such as rheumatoid arthritis. They are also very effective at reducing menstrual pain ( 29, 30, 31).

•ADHD: In children with ADHD, omega-3 supplements can significantly improve various symptoms ( 32, 33).

•Asthma: Omega-3s may help prevent asthma in children and young adults ( 34, 35).

•Baby development: DHA taken during pregnancy and breastfeeding can improve the baby’s intelligence and eye health ( 36, 37, 38).

•Dementia: Some studies link a higher omega-3 intake to a reduced risk of Alzheimer’s disease and dementia ( 39, 40, 41).

Unfortunately, despite improving several risk factors for heart disease, omega-3 fatty acids have not been shown to prevent heart attacks or strokes. The largest studies that look at the body of evidence find no benefit ( 42, 43).

Here is a detailed article about the health benefits of omega-3: 17 Science-Based Benefits of Omega-3 Fatty Acids.


Omega-3 fatty acids have been studied thoroughly. They have been shown to fight depression, reduce fatty liver, lower blood triglycerides and help prevent asthma, to name a few.





Omega 3 Fatty Acids

Omega-3 fatty acids are polyunsaturated fats found in fatty fish such as salmon and sardines. They are also found in walnuts and some seeds, such as chia seeds. They are liquid at room temperature.

Omega-3 fatty acids promote health in several ways. They reduce inflammation and lower the risk of chronic diseases including heart disease, cancer, and arthritis. Omega-3 fatty acids can help lower triglycerides and apoproteins (markers of diabetes), and raise HDL (“good” cholesterol) levels (8).   Omega-3 fats are also essential for brain and eye health (9).

When in the correct balance with omega-3 fats, omega-6 fats are healing fats. Like omega-3 fatty acids, omega-6 fatty acids are polyunsaturated fats. There are healthy and unhealthy sources of omega-6 fats. Healthy sources include sunflower seeds, wheat germ, sesame seeds, and walnuts. When eaten in the ideal ratio with omega-3 fats (between 4:1 and 1:1), these omega-6 fats promote health.

Unfortunately, most Americans follow the Standard American Diet (SAD) and consume a much larger amount of oxidized omega-6 fatty acids found in corn and soybeans than omega-3 fatty acids. This is detrimental to health because an excessive omega-6 level can lead to chronic inflammation which is a cause of many health problems (8).



Health & Human Services, n.d. Web. 24 Apr. 2017.

Polyunsaturated Fats

Polyunsaturated fats are essential fats. We call them essential because they are necessary for human health, but your body cannot synthesize them on its own. You must get them from food. Polyunsaturated fats help stimulate skin and hair growth, maintain bone health, regulate metabolism, and maintain the reproductive system.[7]

There are two main types of polyunsaturated fats. You’ve probably heard of them: omega-6 and omega-3 fatty acids. Omega-6 fatty acids play an important role in brain function and normal growth and development. One essential omega-6 is linoleic acid, which our bodies use to make the lipids that make up our cell membranes.[14] Omega-3s promote heart health and help maintain blood vessels in the brain.[7] Alpha-linolenic acid (ALA) is an essential omega-3 found in plants and a major cardioprotective nutrient.[15]

7″The Truth about Fats: The Good, the Bad, and the In-between.” Harvard Health. Harvard University, Aug. 2015. Web. 24 Apr. 2017.

8″Omega-3 Fatty Acids.” University of Maryland Medical Center. University of Maryland Medical Center, 5 Aug. 2015. Web. 24 Apr. 2017.

9″Types of Fat.” Harvard T.H. Chan School of Public Health. The President and Fellows of Harvard College, n.d. Web. 24 Apr. 2017.

10Chang, C. Y., D. S. Ke, and J. Y. Chen. “Essential Fatty Acids and Human Brain.” Acta Neurologica Taiwanica. U.S. National Library of Medicine, Dec. 2009. Web. 05 May 2017.

11Albahrani, Ali A., and Ronda F. Greaves. “Fat-Soluble Vitamins: Clinical Indications and Current Challenges for Chromatographic Measurement.” The Clinical Biochemist Reviews 37.1 (2016): 27–47. Print.

12″Dietary Guidelines for Americans 2015–2020 8th Edition.” 2015-2020 Dietary Guidelines. The Office of Disease Prevention and Health Promotion, n.d. Web. 05 May 2017.

13″LDL and HDL: ‘Bad’ and ‘Good’ Cholesterol.” Centers for Disease Control and Prevention. U.S. Department of Health & Human Services, n.d. Web. 24 Apr. 2017.

14Ehrlich, Steven D. “Omega-6 Fatty Acids.” University of Maryland Medical Center. University of Maryland Medical Center, 5 Aug. 2015. Web. 24 Apr. 2017.

15Lorgeril, M. De, and P. Salen. “Alpha-linolenic Acid and Coronary Heart Disease.” Nutrition, Metabolism and Cardiovascular Diseases 14.3 (2004): 162-69. Web. 24 Apr. 2017.

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