Omega-3 fatty acids EPA & DHA and the difference between them
Articles
Omega-3s are polyunsaturated fatty acids. The most important are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA take part in many processes in the body and differ in their main role: EPA is most often linked to inflammatory processes, while DHA is a structural component of the brain and the retina. This article explains the difference between EPA and DHA, when to focus on which, how much to take per day and how to support their absorption.
What will you learn in this article?
- Omega-3: EPA, DHA and ALA
- When to choose EPA and when DHA?
- EPA and inflammation
- DHA and children's brain development
- DHA during pregnancy
- DHA and healthy eyes
- How much EPA and DHA per day and how to take them
- Key takeaways
Omega-3: EPA, DHA and ALA
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are omega-3 fatty acids obtained from marine sources, specifically from seaweed and from cold-water fish such as salmon, sardines or mackerel. In contrast, alpha-linolenic acid (ALA) is found mainly in plant sources (for example flaxseed or walnuts) and the body can convert it to EPA and DHA. This conversion is, however, very limited. Because omega-6 fatty acids use the same enzymes in their metabolic pathway, a diet high in omega-6 further reduces the conversion of ALA to EPA and DHA. That is why this article focuses on EPA and DHA.
Which form of omega-3 to prefer and how the sources differ is covered in a separate article, Forms of omega-3: which is best for your health and how do they differ? You can read more about omega-3 from algae in Omega-3 fatty acids from algae or from fish?
When to choose EPA and when DHA?
The biological functions of the individual omega-3 fatty acids are complex, but their main roles differ. DHA is a structural acid found in the brain, skin and retina, and tends to be more relevant where the nervous system and vision are concerned. EPA, on the other hand, is most often studied in connection with inflammatory processes, because it is the starting material for eicosanoids.
| EPA | DHA | |
|---|---|---|
| Main role | linked to inflammatory processes | structural component of brain and retina |
| Where there tends to be more of it | fish and krill oil | algae oil |
| When to focus on it | support in inflammatory states (under research) | brain, vision, pregnancy and childhood |
EPA and inflammation
Inflammation is a natural and necessary reaction of the body to damage. It can be triggered by a pathogen or by a chemical or physical stimulus. Acute inflammation has a protective function and helps heal the injury. The problem is chronic, long-lasting inflammation, which the scientific literature links to civilization diseases.
EPA is a precursor of eicosanoids (prostaglandins, thromboxanes and leukotrienes), which take part in regulating the inflammatory response. That is why EPA is studied in states associated with inflammation.
A review article, "Omega-3 Fatty Acids and Inflammatory Processes" [1], lists diseases associated with the inflammatory response in which omega-3 intake is being studied. They include, for example, asthma and allergies, atherosclerosis, rheumatoid arthritis, Crohn's disease, ulcerative colitis, type 1 diabetes, psoriasis and neurodegenerative diseases. These are areas of research, not a proven therapeutic effect.
Of our supplements, EPA is present in the highest amount in Krill Oil+.
DHA and children's brain development
DHA is an important building block of the brain and takes part in communication between neurons. DHA contributes to the maintenance of normal brain function; the beneficial effect is obtained with a daily intake of 250 mg of DHA. [6] DHA matters most in pregnancy and the first years of life, when the brain develops rapidly: maternal intake of DHA contributes to the normal brain development of the foetus and breastfed infants. For this claim the beneficial effect is obtained with a daily intake of 200 mg of DHA in addition to the recommended daily intake of 250 mg of DHA and EPA for adults. [7]
DHA during pregnancy
Adequate DHA intake in pregnancy supports the child's development and is also studied in other contexts. A 2018 study [2] suggests that DHA supplementation may be associated with a lower risk of preterm birth and low birth weight. A 2020 meta-analysis [3] observed a possible relationship between omega-3 intake and mental wellbeing in late pregnancy and the early postpartum period. These are observations from research, not a proven therapeutic effect.
DHA and healthy eyes
DHA is a structural component of the retina. DHA contributes to the maintenance of normal vision; the beneficial effect is obtained with a daily intake of 250 mg of DHA. [6] Maternal intake of DHA also contributes to the normal development of the eyes of the foetus and breastfed infants (under the same conditions as for brain development). [7]
Beyond the authorised claims, omega-3s are also studied in specific eye conditions. A 12-week 2018 study [4] in contact lens wearers observed less discomfort while wearing them, and another study [5] recorded lower intraocular pressure in normotensive adults after three months of omega-3 supplementation. These are research findings, not a proven therapeutic effect. For a broader look at eye care, see the article How to support eye health.
How much EPA and DHA per day and how to take them
For the maintenance of normal brain function, vision and heart function, an intake of 250 mg of EPA and DHA per day is cited. EPA and DHA contribute to the normal function of the heart at exactly this daily intake. [6] For some goals research works with higher doses, which are best discussed with a doctor or a qualified practitioner.
Omega-3 is best taken with a meal that contains fat. Fats are not soluble in water, so in the small intestine they are first emulsified with the help of bile acids and broken down by pancreatic enzymes, whose release is stimulated by dietary fat. The resulting products form micelles, are absorbed into the intestinal cells as part of chylomicrons and reach the blood through the lymphatic system. Dietary fat therefore improves the absorption of omega-3.
Key takeaways
With omega-3, the source matters: ALA comes mainly from plants, EPA and DHA from fish and seaweed. The conversion of ALA to EPA and DHA is very limited in humans.
EPA is studied in inflammation: it is a precursor of eicosanoids that take part in regulating the inflammatory response, so it is researched in states associated with inflammation.
DHA is key for brain and vision: it contributes to the maintenance of normal brain function and normal vision at a daily intake of 250 mg.
DHA matters in pregnancy: maternal intake of DHA contributes to the normal brain and eye development of the foetus and breastfed infants.
Take omega-3 with fat: dietary fat supports the formation of micelles and chylomicrons, which are essential for absorbing omega-3.
Regular intake is what counts: a long-term daily intake of 250 mg of EPA and DHA supports normal heart function, brain function and vision.
Sources:
[1] Calder PC. Omega-3 fatty acids and inflammatory processes. Nutrients. 2010;2(3):355-374. https://www.mdpi.com/2072-6643/2/3/355
[2] Jackson KH, Harris WS. A Prenatal DHA Test to Help Identify Women at Increased Risk for Early Preterm Birth: A Proposal. Nutrients. 2018;10(12):1933. https://www.mdpi.com/2072-6643/10/12/1933
[3] Zhang MM, Zou Y, Li SM, et al. The efficacy and safety of omega-3 fatty acids on depressive symptoms in perinatal women: a meta-analysis of randomized placebo-controlled trials. Transl Psychiatry. 2020;10:193. https://www.nature.com/articles/s41398-020-00886-3
[4] Downie LE, Gad A, Wong CY, et al. Modulating Contact Lens Discomfort With Anti-Inflammatory Approaches: A Randomized Controlled Trial. Invest Ophthalmol Vis Sci. 2018;59(8):3755-3766. https://iovs.arvojournals.org/article.aspx?articleid=2695024
[5] Downie LE, Vingrys AJ. Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults. Transl Vis Sci Technol. 2018;7(3):1. https://tvst.arvojournals.org/article.aspx?articleid=2680625
[6] Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. Official Journal of the European Union. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32012R0432
[7] Commission Regulation (EU) No 440/2011 on the authorisation and refusal of authorisation of certain health claims (maternal DHA intake and brain and eye development). Official Journal of the European Union. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32011R0440
