What are the benefits of Omega 3 fish oil?

What are the benefits of Omega 3 fish oil?

What is Omega 3?

Omega 3 fish oil is one of the most popular dietary supplements worldwide, known to be important for the body. But do you know the reason why Omega 3 is good for health and what it is?

Omega 3 is made up of what are known as ‘essential fatty acids’. Crucial for the health of everything from the brain to our joints and the optimal function of all our cells, essential fatty acids cannot be made by the human body and must be consumed through diet instead.

The three types of Omega 3 fatty acids required by the human body are called EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid) and ALA (alpha-linolenic acid). The reason why fish oil is so popular as a source of Omega 3 is because it is by far the food type that contains the highest amount of EPA & DHA.

What are the differences between EPA, DHA and ALA?

All three Omega 3 fatty acids are structurally different and are involved in different functions in the body. The most commonly known types are EPA and DHA. Although on the surface it can seem that EPA and DHA have distinctly different benefits, they actually complement one another within the body, with EPA and DHA working together to help every cell function.

For example, DHA is known for being good for the brain, but in fact, EPA is also involved with brain function and health and has been shown in some studies to be more effective than DHA in the treatment of depression. In reality both nutrients are important and work in tandem. Here is a short summary (but by no means fully comprehensive - each would warrant its own post!) of what each fatty acid does.

What is EPA?

EPA is well-known to act as an anti-inflammatory within the body, and as such can be beneficial in all disorders driven by inflammation, whether that be arthritis, coronary heart disease, inflammatory skin conditions or any other.

What are the benefits of EPA?

A combination of EPA and DHA may benefit cardiovascular health by decreasing inflammation and helping keep arteries healthy, moderating blood pressure, as well as reducing blood levels of triglycerides.

Triglycerides are fats that are produced in the body as part of breaking down of the food we eat. High levels of triglycerides are known to contribute to the thickening of arteries which can stop the heart and cardiovascular system from working normally, so it’s important to keep levels within the healthy range, which can be checked by your GP.

EPA is crucial for chemical signalling between brain cells and is important along with DHA for brain and mental health. Having been shown to reduce cellular inflammation in the brain, it is an essential nutrient for helping manage mood disorders, preventing or delaying degenerative brain diseases, and keeping the brain healthy for as long as possible.

What is DHA?

DHA Omega 3 fatty acid is found in large amounts in the brain, and as such is known to be important for all aspects of brain health and function. In fact, DHA is one of the primary nutrients involved with the development of our whole nervous system. It is especially important for the development of the human brain in utero, with DHA in Omega 3 forming and maintaining much of the brain’s structural material including cell membranes and neurons. DHA is an extremely important nutrient to be ingested during pregnancy not only for all the aforementioned reasons, but also for the healthy development of baby’s eyes.

What are the other benefits of DHA?

Consuming adequate quantities of DHA alongside EPA is associated with a reduced risk of depression and there have been many studies in this area. One large-scale study involving roughly 22,000 adults in Norway showed that those who reported taking fish oil daily — providing 300–600 mg each of DHA and EPA — were around 30% less likely to have symptoms of depression.

Some studies suggest that DHA may help delay the symptoms of age-related degenerative brain diseases such as Alzheimer’s disease.

When it comes to healthy skin function, DHA is involved in creating and maintaining moist and healthy skin cells. A combination of DHA and EPA in omega 3 fish oil benefits skin by helping to decrease inflammation and ‘moisturising’ the cell membrane. In turn this can help improve the health and appearance of the skin - for example in the case of conditions such as eczema or dry skin.

DHA helps keep our eyes healthy and has been shown to be beneficial in the management of age related macular degeneration (AMD).

What about ALA?

Fish have the clever ability to take up ALA from their food sources and convert it to EPA and DHA, which we benefit from when we eat it. Unfortunately, we humans are nowhere near as efficient as fish at converting ALA from plant foods. Despite the fact that ALA can be found in abundance in our diet, only a tiny amount of the ALA we consume converts to DHA and EPA, with estimates being around 5% to EPA and approximately 0.5% to DHA. For optimal health, we need much more, which is why oily fish is commonly known to be so good for us.

Plant foods that contain ALA Omega 3

Sources of ALA include vegetable oils, flaxseed and nuts, all of which are healthy foods to be included in the diet. Given the poor capacity for humans to convert ALA to EPA and DHA, the ALA obtained from plant sources such as nuts and seeds shouldn’t be relied upon as the sole source of Omega 3.

nuts and seeds

If you don’t eat fish, fear not, below we discuss how vegans and vegetarians can increase their intake of DHA and EPA.

What do omega 3 fatty acids EPA & DHA do?

In summary, a combination of the Omega-3 fatty acids EPA and DHA from fish oil have been scientifically proven to:

  • Be an essential nutrient for brain health
  • Contribute to the normal function of the heart and good cardiovascular health
  • Contribute to the normal brain and eye development of a foetus and breastfed infants when ingested by the mother
  • Contribute to the maintenance of normal vision and brain function
  • May help improve joint health
  • Anti-inflammatory
  • May improve skin health (and appearance!)

Can't I just get my intake from eating fish?

There is an argument to suggest that we can get the fats we need from eating oily fish a couple of times a week, but the doses of Omega-3 can be variable depending on the quality and type of fish, and where it was sourced. More importantly, the science shows that high doses confer more significant health benefits; many studies suggest 3000mg per day which is extremely hard to obtain through diet alone, and these doses cannot be obtained through eating fish a couple of times a week.

What are Nutrient Reference Values (NRVs) and why are they so much lower than doses in many supplements?

Nutrient reference values (NRVs) - previously known as RDA (Recommended Daily Allowance) values that you may have seen on the back of food and supplement packets - refer to doses of nutrients as an indicator of the minimum requirement for the human body to maintain health, given average environment and diet. The NRVs do not refer to the values required for our best health, which is why supplements of certain nutrients can be important and often used in significantly higher doses than NRVs, particularly where there is a therapeutic need.

What about the risk of mercury toxicity?

You may have read about potential mercury toxicity being linked to the excess consumption of certain types of oily fish. One of the benefits of supplementing with fish oil is that you have control over the quality of the product you are buying and have the option of selecting an ultra-pure quality fish oil that has been checked for contaminants such as mercury.

I am vegan, how can I get a good intake of omega-3?

As mentioned above, there are plant-based foods which contain omega-3 fatty acids. However, there are different types of Omega-3, the most important being EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) which are found almost exclusively in oily fish and seafood. As mentioned above, ALA (alpha-linolenic acid) is the kind of Omega-3 found in plant foods such as nuts, seeds and vegetable oils, and although the human body can convert ALA into DHA and EPA we only have the capacity to do so in very small amounts.

We recommend that vegans source a vegan EPA/DHA supplement to take regularly for their own health, especially when pregnant. These supplements can be expensive, particularly when trying to achieve a therapeutic dose, but you should aim to obtain a minimum of 300mg DHA per day during pregnancy. Most vegan Omega 3 supplements contain much less than this, so you may need to take several capsules to obtain enough.

How much Omega 3 fish oil should I be taking?

For general health, experts recommend a minimum of 500mg Omega-3 as EPA/DHA and at 1000-3000mg for people with health concerns.

Are there any contraindications to taking Omega 3 fish oil?

One of the effects of Omega 3 fish oil supplements is to thin the blood, which can be beneficial if you’re hoping to reduce the risk of blood clots. The blood thinning effect of Omega 3 can increase the risk of bruising and bleeding in those who might be undergoing a surgical procedure, so it is best to advise your doctor if you have been taking them and we normally recommend that patients abstain from taking fish oils from two weeks prior to a procedure.  

Patients taking any blood thinning medication such as Warfarin shouldn’t use Omega 3 fish oil supplements.

If you enjoyed reading this article, you might like Health benefits of Lactobacillus Rhamnosus GG.


The Institute for Food Brain and Behaviour (IFBB)

McNamara R. K. (2016). Role of Omega-3 Fatty Acids in the Etiology, Treatment, and Prevention of Depression: Current Status and Future Directions. Journal of nutrition & intermediary metabolism, 5, 96–106. doi:10.1016/j.jnim.2016.04.004

Cole GM, Frautschy SA. DHA may prevent age-related dementia. J Nutr. 2010;140(4):869–874. doi:10.3945/jn.109.113910

TSO (The Stationary Office) Scientific Advisory Committee on Nutrition (Sacn) and Committee on Toxicology (Cot). Advice on Fish Consumption: Benefits and Risks. TSO (The Stationary Office); Norwich, UK: 2004.

Kris-Etherton P.M., Harris W.S., Appel L.J. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002;106:2747–2757.

Global Organisation for EPA and DHA (GOED) Global Recommendations for EPA and DHA Intake. Available online: http://www.goedomega3.com/index.php/files/download/304.

Post author

Aliza Marogy

Nutritional Therapist, ND & Founder of Inessa