What is omega-3 and how do I get it?

1       What is Omega-3?

Omega-3 fatty acids are fatty acids that can be found in walnuts, flax seeds, chia seeds, salmon, mackerel and dietary supplements such as fish and algae oil. These fatty acids can be obtained from both plants and animal sources. However, those who practice a plant-based diet will be consuming more of the more of one and less of another, and vice versa for those consuming a mixed diet. The three main omega-3 fatty acids are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). Remembering the scientific names is unnecessary, ALA, EPA & DHA is more than enough to retain throughout this article. Just know ALA is found in plant-based food and EPA & DHA is found predominantly in animal-based foods, although there are exceptions, such as algae oil.

Plant-based (ALA) = flaxseed oil, soybean oil, walnuts, chia seeds

Plant-based (EPA & DHA) = algae oil supplements

Animal-based (EPA & DHA) = Salmon, mackerel, herring, fish oil supplements

1.1      What does Omega-3 do in the body?

Omega-3 fatty acids are important as they provide structural support for all the cells in our body. For example, DHA is particularly high in the brain, eye and sperm cells – supporting cognition, vision and reproductive health (Figure 1). EPA has an integral role in supporting our heart, immune system, blood vessels and various endocrine glands which produce hormones (Figure 1). Interestingly, these omega-3 fatty acids have quite different biological fates once ingested: ALA can be converted into EPA which can then be converted to DHA and DHA can be retro-converted in EPA (Figure 3). Although, as with everything in biology it is not that simple and straightforward.

**Plant-based will be used interchangeably with = Vegan/Vegetarian

2       DHA, EPA & ALA

The easiest way to comprehend the contrasting roles of EPA and DHA in the body is to think of them as your left and right hand. You need both or at least are better off with both. EPA plays a functional role in the body - similar to how electricity works in any building. While DHA has a structural role - similar to bricks in a wall providing support.

DHA is incorporated into our cell membranes which provide structure and allows it to function normally. DHA supports brain function and eye health. It is imperative for pregnant and breastfeeding mothers to supplement or obtain adequate DHA through fortified products (additional 200 mg/day on top of the diet) to support eye and brain development of the foetus. The biological effects extend to the regulation of blood pressure, heart rate and fat metabolism. It has also been shown to prolong gestation and improve immune development and function.

EPA supports local inflammatory responses, for example, if you twisted your ankle and it became inflamed, EPA would exert its effect locally at the ankle joint. Which is completely different from whole-body systemic inflammation, but that is a conversion for another day, although the distinction is important. Most individuals think inflammation is bad, but as previously mentioned biology is complex, inflammation can be both good and bad, context determines its classification. EPA also contributes to maintaining normal circulating fatty acid concentrations and regulating mood. While both EPA & DHA effects are presented/laid-out in isolation, in reality, these are quite complex, and a host of factors influence their role and effects in the body. It is presented this way purely for understanding and comprehension.

ALA  the final omega-s of the trio, the recommendation in the United States is 1.6 g and 1.1 g a day for men and women, respectively. In Europe, it is 0.5 % of energy intake with no gender-specific recommendations. For example, a typical 2000 kcal diet would require 1.1 g a day, so very similar just different units for communicating the message. With some slight deviations in the total amount. In practice, this does not matter, as most individuals have a nutrient/food target and do not meticulously track/plan every gram of food to ensure they hit all their nutrient needs. Importantly, this approach is also not needed.

Figure 1: Physiological roles of EPA & DHA in the body.

The conversion efficiency of ALA to EPA and finally DHA is quite varied for males and females and also affected by age, for example;

  • Healthy young men can convert roughly:

o   8% of ALA - EPA

o   0.4% of EPA - DHA

  • Healthy young women can convert roughly:

o   21% of ALA - EPA 

o   9% of EPA - DHA


Herein lies the challenge, based on the above examples, there would need to be some serious planning to reach EPA & DHA concentrations from ALA sources. The values presented above are averages of a sample of people from the population. You as an individual could be on the low, normal, or the high end for conversion efficiency. Always remember this, most blogs/articles will report study averages but that doesn’t inherently mean that it applies to you as an individual.

To obtain the equivalent amount of EPA & DHA from ALA one would have to eat approx. 10 times the amount, and still, have a large degree of uncertainty regarding their DHA status. Importantly, these recommendations are constructed from observing the omnivorous diet, so consuming even higher amounts of ALA may be sensible for those following a plant-based diet.

Important points to remember are:

  • ALA conversion to DHA is dismally low, seems unattainable from ALA intake.
  • Producing adequate EPA may be attainable with large ALA intakes.

Naturally, this leads to the idea of supplementing with pre-formed EPA & DHA, unless you want to consume copious amount of ALA and hope for the best.

2.1      Deficiency Symptoms/Signs

The criteria to deem an individual deficient in DHA & EPA have yet to be determined by any national nutrition body, although impaired functional capacity can be indicative; vision, skin and cognitive processes (Figure 2). A deficiency can result in rough, scaly skin and in some cases dermatitis. It has also been suggested that deficiency can lead to water loss and impaired learning ability.

The scientific literature suggests that DHA decreases when adopting a vegan or vegetarian diet, however, there seems little to no evidence to support adverse effects. Importantly, the absence of evidence is not evidence of absence. Notably, DHA is a long-chain fatty acid and its only source is from algae for vegan/vegetarians, so on the contrary – if there are known health benefits from obtaining adequate DHA it would be sensible to pursue, in light of no detrimental effects been detected from lower blood levels.

In Table 1 the European Food Safety Authority (EFSA) authorized health claims are presented, these are the claims that undergo rigorous scientific investigation & scrutiny before been accepted by a board of subject matter experts on omega-3 fatty acid health benefits. This is a great place to distinguish the science from the sensationalism when evaluating any supplement or product.

Figure 2: Complications associated with omega-3 deficiency.

3       Plant-Based Diets & Omega-3

The traditional line of thinking for plant-based dieters and obtaining sufficient omega-3 goes as so:

“just consume adequate ALA and that can be converted into EPA and subsequently DHA”

Unfortunately, it is not this simple as we have seen in the previous section, with conversion efficiency examples. Obviously, those who follow a vegetarian/vegan diet will only obtain ALA and zero EPA & DHA from their diets unless a supplement is used.

Although many beneficial characteristics have been attributed to vegan and vegetarian dietary practices, lower DHA status is seen across the board irrespective of the quote on quote “healthy vegan diet” or “unhealthy vegan diet”. Having a nutritious diet doesn’t salvage the important fatty acid DHA.

Side note: In research, the fatty acid concentration is calculated by using the sum of EPA and DHA in red blood cells and expressing it as a percentage of total fatty acids.

Furthermore, omega-3 fatty acids EPA & DHA may have significant preventative and therapeutic effects depending on the individual, dose and condition. High intakes have been associated with decreased risk of inflammatory disease and depression, further illustrating its wide-reaching effects.

The evidence that vegans need to go beyond the recommended ALA intakes is mixed and complicated. Although we feel that if an individual is meeting the ALA recommendations EPA deficiency is not of concern, or at least has shown no immediate signs of concern within the scientific literature. Conversely, obtaining adequate DHA from ALA is highly unlikely, unless you have a rare genotype (genetics you have) that is super-efficient with the conversion, also highly unlikely. Figure 3 below depicts a simplified version of the chain of reactions for ALA – EPA - DHA. Illustrating why EPA is more easily obtained from ALA compared to DHA, as it requires fewer steps and is the first reaction of ALA conversion.

Vegans have been encouraged to boost their EPA & DHA status by increasing ALA intake and decreasing a short-chain omega-6 fatty acid called linoleic acid (LA). Depending on the context excessive LA can theoretically interfere with the conversion of ALA - EPA because ALA & LA need the same enzyme for conversion into EPA & AA (see Figure 3). High LA intakes are observed with plant-based diets adding fuel to the fire that if you want to be sure you are meeting omega-3 fatty acid requirements, supplementation is most reliable.

Finally, meeting DHA recommendations from ALA intake especially for men is quite the stretch and those following plant-based diets have consistently shown lower omega-3 levels upon testing. Think back to the example provided earlier form research where men had a substantially lower capacity for conversion compared to women. An important consideration for the individual.

Figure 3: Simplified version of omega-3 & 6 pathways. 


4       Authorised Health Claims

Table 1: Approved health claims for omega-3 fatty acids from EFSA.



Health Relationship

Alpha-linolenic acid (ALA)


ALA contributes to the maintenance of normal blood cholesterol levels


Maintenance of normal blood cholesterol concentrations


Docosahexaenoic acid (DHA)


Docosahexaenoic acid (DHA) maternal intake contributes to the normal brain development of the foetus and breastfed infants.

Normal brain development of the foetus and breastfed infants.


Docosahexaenoic acid (DHA)


Docosahexaenoic acid (DHA) maternal intake contributes to the normal development of the eye of the foetus and breastfed infants.


Normal development of the eye of the foetus and breastfed infants.


Eicosapentaenoic acid and docosahexaenoic acid (EPA/DHA)


EPA and DHA contribute to the normal function of the heart


Maintenance of normal cardiac function


Docosahexaenoic acid (DHA)


DHA contributes to maintenance of normal brain function


Contributes to maintenance of normal brain function

Docosahexaenoic acid (DHA)


DHA contributes to the maintenance of normal vision


Contributes to the maintenance of normal vision


Docosahexaenoic acid (DHA)


DHA contributes to the maintenance of normal blood triglyceride levels


Maintenance of normal (fasting) blood concentrations of triglycerides


Docosahexaenoic acid and Eicosapentaenoic acid (DHA/EPA)


DHA and EPA contribute to the maintenance of normal blood pressure


Maintenance of normal blood pressure


Source: EU register of nutrition and health claims.

The health claims detailed above exemplifies the biological need for EPA & DHA to maintain/support a wide array of functions from regulating blood pressure all the way to supporting normal vision.


5       Algae Oil vs Fish Oil

Finally, the last section, thanks for sticking with us thus far. This is the most interesting and controversial area by far. Research to date has investigated relatively small dosages of algae oil and observed substantial increases in vegan and vegetarian DHA levels.

Supplementation over four weeks has been seen as sufficient to observe increases in DHA status. Moreover, decreases have been observed in plasma triglycerides (circulating fats in the blood) up to 23%. Some of the intervention trials monitored participants for side effects and symptoms of toxicity, all studies reported that the algae oils were well tolerated, safe and provided a bioavailable source of DHA

On the other hand, consuming fish oil compared to algae oil increases the risk of the body accumulating heavy metals such as mercury, lead, nickel and cadmium. Although, heavy metal toxicity from fish oil is still highly unlikely as the actual heavy metals selectively bind with the protein rather than accumulate in the oil. Most fish oils pass safety standards for potential contaminants, but not all. The processing and handling of fish oils are also other areas of concern. The council for responsible nutrition and the World Health Organization have acceptable standards regarding contaminants in fish oil on their websites if interested in further reading on the matter. However, supplementing with Algae oil removes the worry and the need to scrutinize fish oil supplements.

Production of algae oil is conducted in highly controlled fermentation facilities with rigorous quality control resulting in a high-quality omega-3 product. Fortification of plant-based milk and infant formula is only the start of this oil’s inclusion into the food supply. Algae oil provides halal, vegetarian, kosher and vegan sources of omega-3 fatty acids that are potent, effective and safe to consume. Finally, it is a fantastic alternative to fish or krill oil, if that is outside your remit or preference. Table 2 below provides an objective summary of algae oil vs fish oil.

Overall, experimental research has shown algae oil to be effective and efficient in raising DHA levels in humans. Algae oils show certain advantages compared to fish oil such as

  • sensory properties
  • consistency of omega-3 compositions
  • lower risk of contamination
  • sustainability and the ease of production.
  • environmentally friendly

Algae oils do not possess odours making it a suitable supplement for those adverse to fish odour. In addition, algae oil produces higher yields compared to fish oil production making it a sustainable and environmentally-friendly choice. Omega-3 intake is low in the western world, as a result most health professionals recommend supplementation for people who do not obtain adequate amounts through the diet – such as plant-based diets. 


Table 2:  Overview of Fish oil vs Algae oil.



Can contain heavy metals

  Heavy metal free

 Environmentally unsustainable

 Environmentally sustainable

 Fishy odour

 No odour

 Only suitable for omnivores

 Suitable for vegans & vegetarians

 Huge variability depending on fish

✓ Consistent fatty acid composition


6       Summary

Studies published to date show, with few exceptions, that EPA and DHA intakes and status in vegetarians and vegans are lower than in omnivores. Supplementation is the only proven route to increase omega-3 status in these populations in light of dietary constraints. In addition, infants born to vegan mothers have lower DHA status than those born to omnivore mothers making supplementation extremely important during pregnancy and breastfeeding.

The fatty acid ALA is inefficiently converted to longer-chain omega-3 fatty acids EPA & particularly DHA. There are no suitable sources of EPA & DHA other than algae for those who follow a vegan diet. Supplementation is the easiest means of obtaining reliable, sustainable, safe and effective omega-3  fatty acids when following a plant-based diet.  

Figure 4: Summary of the areas omega-3 can benefit.


7       FAQs

  1. Does fish oil contain the omega-6 Arachidonic Acid (AA)?
    1. Yes, fish oil unlike, olive, soybean and coconut oils contain AA, which has many critical functions in the body such as regulating blood pressure and immune function.
  2. What foods provide EPA & DHA?
    1. Certain algae are a natural source of DHA and EPA, fatty fish such as mackerel, herring, salmon, tuna, anchovies and DHA fortified food and beverages.
  3. How much EPA & DHA do I need?
    1. Intake of 250 mg of DHA & EPA per day has been associated with decreased risk of CVD. But unfortunately, there are no blanket recommendations available. For example, some studies have supplemented up to 8 g of DHA a day in certain populations. However, 250 mg of DHA & EPA per day seems like a good starting point.
  4. Can I consume flax oil instead of algae oil?
    1. The omega-3 fatty acid found in flax oil and chia oil is ALA. As mentioned in the article this form is not sufficient to supplement on its own. Supplementation with flax oil is not enough. Although consuming 2 g of ALA has been associated with a reduced risk of heart disease in vegetarian subjects. 
      1. Here is a great read if interested in delving further into the science - https://pubmed.ncbi.nlm.nih.gov/9001371/
  5. Is EPA found in the brain?
    1. EPA is found in negligible amounts in the brain.
  6. Do vegans need an EPA Supplement? 
    1. As always it depends, but if ALA intake is sufficient, EPA supplementation may not be needed. However, this is difficult to measure, it is typical for humans to get more DHA than EPA. Take fish for example which has about twice as much DHA to EPA.


The information provided in this article should not take the place of medical advice. We encourage you to consult with your healthcare provider regarding any supplementation as each individual is different and supplements may behave differently with those who medicate or have underlying conditions. This material is to be used for educational purposes ONLY.