Omega-3 fatty acids are incredibly important. They must be sourced from your diet as the body cannot produce it on its own. Rather than being stored or used for energy like other fats, they play important roles in many bodily processes, such as inflammation, heart health, and brain function.

In this article you can find:

  • What is omega-3?
  • Types of omega-3s – AHA, EPA and DHA
  • What are the benefits of omega-3?
  • What are the signs and symptoms of deficiency?
  • Who is at risk of deficiency?
  • Sources of omega-3 and recommended dose

What is Omega-3?

Omega-3 is a type of polyunsaturated fatty acid (PUFA - the type of unsaturated fatty acid that contains two or more double bonds). Unsaturated fats are referred to as the "healthy fats" as they can improve "good" (HDL) cholesterol levels in the body. Saturated fats are referred to as the "unhealthy fats" as too much saturated fat can cause "bad" (LDL) cholesterol to build up in your arteries (blood vessels). Omega-3s are deemed as an essential fatty acid (EFA) because they're necessary for health and cannot be made by the body. They are important components of the cellular membranes of all tissues in your body. The enrichment of membranes with omega-3 fatty acids can modulate cellular signalling events, membrane protein function and gene expression (1).

Types of Omega-3s – AHA, EPA AND DHA

Out of the 11 types of omega-3 fatty acids, alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are the three most important. ALA is found mainly in plant oils, whereas DHA and EPA are found in fish and other seafood. Alpha-linolenic acid (ALA) is the most abundant omega-3 fatty acid found in the diet, however it needs to be converted into EPA or DHA before the body can use it for something other than energy. This conversion process is inefficient in humans, as only a small amount of ALA is converted into EPA and even less into DHA (2). The remaining amount is then stored or used as energy. The body utilizes EPA to produce signalling molecules (eicosanoids) which are involved in several physiological roles and reduce inflammation (3). DHA is important for brain development and is a significant structural component of your skin and the retinas in your eyes.

What are the Benefits of Omega-3?

Omega-3 fatty acids have countless health benefits, which makes them vital for optimum health. Below are some of the many aspects of health which omega-3 fatty acids have been shown to impact.

Mental Health Disorders

Omega-3 is an essential component of the neurotransmitter serotonin, which is known to improve mood. Studies suggest that those who consume omega-3s regularly, reduce the likelihood of having depression (4). In addition, some studies have indicated when those with mood disorders, including depression, anxiety and ADHD started supplementing with omega 3, their symptoms started to improve (5). It has also been found to have a positive impact on other mental conditions, such as bipolar disorder, schizophrenia and borderline personality disorder, particularly in lessening the symptoms of depression or delaying onset. However, the overall evidence is mixed, and more research is needed to be conducted. EPA seems to be the most effective at combating depressive symptoms amongst mental health disorders (6).

Eye Health

DHA is a key structural component of your eyes' retinas. Studies suggest that consumption of DHA may help prevent macular degeneration (a common eye disorder in older adults that causes blurred or reduced central vision as a result of macula thinning) (7).

Heart Health

Omega-3s have also been linked to several heart health benefits. For example, they have shown to reduce the prevalence of triglycerides (a type of fat found in the blood that can increase the risk of heart disease), reduce blood pressure, increase levels of "good" (HDL) cholesterol, reduce the formation of blood clots and prevent buildup of plaque in the arteries (8).


Inflammation is the body's immune system's response to an infection or injury. In some circumstances, inflammation can persist for extended periods, even without an irritant. This is referred to as chronic inflammation. Research has continually linked the relationship between reduced inflammation with higher omega-3 intake. This is as a result of omega-3 fatty acids lessening the production of some substances released during the body's inflammatory response (inflammatory eicosanoids and cytokines) (9).

Brain Health

The human brain is approximately 60% fat, which is why regular consumption of omega-3 fatty acids will help support brain health and vitality. Inadequate consumption can result in the myelin sheath surrounding nerve cells to deplete, meaning messages being sent through the brain slow down or stop, resulting in poor concentration. Many studies have also associated higher omega-3 intake with decrease age-related mental decline and a decreased risk of developing Alzheimer's disease (10). However, more research is needed in this area.

Skin Health

Similar to the eyes, DHA is also a major structural component of the skin and plays a key part in the health of the skin's cell membranes (contributing to younger looking skin). EPA also benefits the skin by managing oil production, hydration and helping to block the release of substances that reduce college levels in the skin after your skin has been exposed to the sun (11).


Metabolic syndrome is a cluster of conditions that occur together, increasing the risk of type 2 diabetes, heart disease and stroke. Omega-3 fatty acids are present in the most metabolically active cells in the body. As a result, they can reduce symptoms of metabolic syndrome such as weight gain, high blood pressure, insulin resistance, high triglycerides and low "good" (HDL) cholesterol levels (12).

What are the signs and symptoms of deficiency?

Signs and symptoms of deficiency can include:

  • Rough, scaley skin and dermatitis (itchy, dry skin or a rash on swollen reddened skin e.g. eczema, dandruff)
  • Hair loss and brittle nails
  • Poor concentration and attentiveness
  • Depression
  • Joint pain
  • Weight gain/obesity
  • Eyesight problems
  • Fatigue
  • Cardiovascular concerns

Who is at Risk of Deficiency?

Omega-3 deficiency can occur across the population spectrum. However, this risk increases for those again who:

  • Eat an inadequate amount of fish or seafood
  • Those with particular chronic diseases
  • Those consuming a diet of fat restriction
  • Those consuming a low-calorie diet (the body can release essential fatty acids from adipose tissue reserves to compensate) (13)

Sources of Omega-3 and Recommended Dose

Food sources of Omega-3s include:

  • Salmon
  • Shark and marlin
  • Sardines
  • Swordfish
  • Mackerel
  • Kippers
  • Trout (Rainbow)
  • Fresh Tuna (tinned tuna loses its omega 3 during the manufacturing process)
  • Herring
  • Pilchards

It is recommended that we consume 2 portions of fish per week.

While plant sources are less reliable sources of EPA and DHA, plant sources of omega-3s include:

  • Oils (rapeseed, canola, walnut, soya, flaxseed, linseed)
  • Dark leafy green vegetables (spinach and kale)
  • Nuts (almonds, walnuts, peanuts)
  • Soya and soya products
  • Omega-3 enriched foods (yoghurt, milk, spread, orange juices)

Supplemental sources include:

There are a variety of omega-3 containing supplements currently available. When choosing a supplement, ensure to read the nutritional information and add up the amount of EPA and DHA to calculate the total omega-3 fatty acids. If ALA or flaxseed oil appears as a source of omega 3, it should be disregarded as this source is not as reliable as EPA or DHA in the body.

The Food and Drugs Administration recommends that individuals do not exceed more than a total of 3g per day of EPA and DHA omega 3 fatty acids, with no more than 2g per day from a dietary supplement. Some people may need larger amounts under supervision of a medical professional (14).

For people deficient in omega-3, this is a cheap and highly effective way to improve health.


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  2. Burdge, G., 2006. Metabolism of α-linolenic acid in humans. Prostaglandins, Leukotrienes and Essential Fatty Acids, 75(3), pp.161-168.
  3. Ricciotti, E. and FitzGerald, G., 2011. Prostaglandins and Inflammation. Arteriosclerosis, Thrombosis, and Vascular Biology, 31(5), pp.986-1000.
  4. Grosso, G., Galvano, F., Marventano, S., Malaguarnera, M., Bucolo, C., Drago, F. and Caraci, F., 2014. Omega-3 Fatty Acids and Depression: Scientific Evidence and Biological Mechanisms. Oxidative Medicine and Cellular Longevity, 2014, pp.1-16.
  5. Ginty, A. and Conklin, S., 2015. Short-term supplementation of acute long-chain omega-3 polyunsaturated fatty acids may alter depression status and decrease symptomology among young adults with depression: A preliminary randomized and placebo controlled trial. Psychiatry Research, 229(1-2), pp.485-489.
  6. Jazayeri, S., Tehrani-Doost, M., Keshavarz, S., Hosseini, M., Djazayery, A., Amini, H., Jalali, M. and Peet, M., 2008. Comparison of Therapeutic Effects of Omega-3 Fatty Acid Eicosapentaenoic Acid and Fluoxetine, Separately and in Combination, in Major Depressive Disorder. Australian & New Zealand Journal of Psychiatry, 42(3), pp.192-198.
  7. Merle, B., Benlian, P., Puche, N., Bassols, A., Delcourt, C. and Souied, E., 2014. Circulating Omega-3 Fatty Acids and Neovascular Age-Related Macular Degeneration. Investigative Opthalmology & Visual Science, 55(3), p.2010.
  8. Wang, Q., Liang, X., Wang, L., Lu, X., Huang, J., Cao, J., Li, H. and Gu, D., 2012. Effect of omega-3 fatty acids supplementation on endothelial function: A meta-analysis of randomized controlled trials. Atherosclerosis, 221(2), pp.536-543.
  9. Calder, P., 2006. n−3 Polyunsaturated fatty acids, inflammation, and inflammatory diseases. The American Journal of Clinical Nutrition, 83(6), pp.1505S-1519S.
  10. Fotuhi, M., Mohassel, P. and Yaffe, K., 2009. Fish consumption, long-chain omega-3 fatty acids and risk of cognitive decline or Alzheimer disease: a complex association. Nature Reviews Neurology, 5(3), pp.140-152.
  11. Spencer, E., Ferdowsian, H. and Barnard, N., 2009. Diet and acne: a review of the evidence. International Journal of Dermatology, 48(4), pp.339-347.
  12. Kaur, J., 2014. A Comprehensive Review on Metabolic Syndrome. Cardiology Research and Practice, 2014, pp.1-21.
  13. 2020. Office Of Dietary Supplements - Omega-3 Fatty Acids. [online] Available at: [Accessed 26 October 2020].
  14. 2020. What's The Catch With Omega 3'S? - INDI. [online] Available at: [Accessed 26 October 2020].