The Significance of Omega-3 Fatty Acids in Our Diet
Tomasz Jankowski
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Diets Premium Expert • 24.03.2026
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Scientifically reviewed by a clinical dietitian:
This article has been peer-reviewed for adherence to IŻŻ, WHO, and PTGiP clinical nutritional standards.
| Diets Premium Expert Tomasz Jankowski | min read 7 min | Scientifically reviewed by a clinical dietitian 24.03.2026 |
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Key Takeaways
Omega-3 fatty acids, which are key components supporting human health, should be part of our daily diet. What are these substances and what properties do they possess? Where can we find them?
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Omega-3 fatty acids
Omega-3 fatty acids are an essential group of unsaturated fatty acids that contain double bonds and are critical for proper human function. The body cannot synthesize them on its own, so they must be supplied through diet. Among the omega-3s are: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Within the body, alpha-linolenic acid (ALA) is converted into eicosapentaenoic acid (EPA), and then into docosahexaenoic acid (DHA). These fatty acids are biologically active and have a positive impact on the human body. However, the conversion of ALA into EPA and DHA occurs to a limited extent and depends on gender. In men, the conversion of ALA into EPA ranges from 0.3 to 8%, while the conversion into DHA is less than 1%. In women, ALA is converted into EPA in about 21%, while the conversion into DHA is 9%. The higher content of EPA and DHA in women is associated with the higher demand for DHA during pregnancy and breastfeeding.
Polyunsaturated omega-3 fatty acids - their significance for the body
Polyunsaturated omega-3 fatty acids play a critical role in the functioning of the human body. They are components of cell membranes, influence the regulation of gene expression and cellular metabolism, and exhibit immunoprotective and anti-inflammatory properties. They improve memory and cognitive processes, reduce the risk of developing heart and circulatory diseases, lower the frequency of allergies, and decrease the risk of developing Alzheimer's disease and dementia. They are essential for proper prenatal development and increasing birth weight, and also affect the development of the nervous system, visual organ, and cognitive development in small children. Docosahexaenoic acid (DHA) is responsible for the maturation of the retina and the part of the cerebral cortex responsible for vision and visual acuity, while eicosapentaenoic acid (EPA) exhibits properties that regulate the functioning of the immune system.
Omega-3 fatty acids as the source
The primary source of ALA is plant oils, including those from rapeseed, flaxseed, soybeans, as well as walnuts, green plant parts, and certain legumes. EPA and DHA are found in abundance in fatty marine fish such as herring, salmon, tuna. In addition, they can also be found in seaweed and marine phytoplankton. The content of docosahexaenoic and eicosapentaenoic acids in fish varies depending on their species and physiological state, habitat, and season. Wild fish tend to have a higher content of omega-3 fatty acids than farmed fish.
Amount of omega-3 fatty acids in selected fish varieties (E. Materac et al. 2013):
– Salmon 1.4–1.9 g/100 g, – Herring 1.2–1.7 g/100 g, – Mackerel 1.0–2.5 g/100 g, – Trout 0.7–1.0 g/100 g, – Canned tuna 0.7–1.0 g/100 g, – Flounder 0.4 g/100 g.
Organism's necessity for omega-3 fatty acids
The dependence of the body's requirement for omega-3 fatty acids on its age, physiological status (pregnancy, breastfeeding) and health status. Recommendations for adequate intake of omega-3 (AI) (Jarosz M. et al. 2020). Infants (7-24 months) - ALA: 0.5% energy, DHA: 100 mg/day. Children (2-18 years) - ALA: 0.5% energy, DHA + EPA: 1-2 servings of fish or seafood/week, including fatty fish, or 250 mg/day. Adults - ALA: 0.5% energy, DHA + EPA: 1-2 servings of fish or seafood/week, including fatty fish, or 250 mg/day. Pregnant women - ALA: 0.5% energy, DHA + EPA: 250 mg/day + 100-200 mg DHA/day. Breastfeeding women - ALA: 0.5% energy, DHA + EPA: 250 mg/day + 100-200 mg DHA/day.
Insufficiency of Omega-3 Fatty Acids
An insufficiency of Omega-3 Fatty Acids may lead to: - impairment of the operation of multiple organs, including the kidneys, liver, heart, and side effects of blood platelets, - decrease in the number of blood platelets, - development of an inflammatory state, - visual disturbances, - increased risk of cardiovascular diseases and Alzheimer's disease, - disorders of the nervous system, particularly during prenatal life and in young children.
Exorbitant omega-3 fatty acids
As of yet, no detrimental consequences have been observed resulting from excessive consumption of omega-3 fatty acids. However, it is not recommended to consume larger doses in the form of supplements, particularly if anticoagulant medications are also being taken. It is challenging to overdose on omega-3 fatty acids through food consumption.
Omega-3 Fatty Acids and their Impact on Circulatory System Disorders
In the Mediterranean countries and Japan, there are fewer cases of cardiovascular disease than in Western countries, which may be due to the increased intake of fish and seafood by the populations of those regions, which are a rich source of omega-3 fatty acids. The positive effects of omega-3 fatty acids (EPA and DHA) on the circulatory system are associated with their strong anti-inflammatory and improved cellular function. Inflammatory markers trigger the synthesis of CRP protein, with an increased level associated with an increased risk of developing cardiovascular diseases. However, the results of the studies are not unequivocal: on the one hand, E. M. Balk and A. H. Lichtenstein in their meta-analysis showed that omega-3 fatty acids have a minor impact on LDL and HDL lipoprotein levels, but a significant impact on triglyceride levels; while ALA has no effect on arterial blood pressure parameters (E. M. Balk, A. H. Lichtenstein 2017). On the other hand, Y. Hu et al. in their meta-analysis from 2019 showed that supplementation with EPA and DHA lowers the risk of heart attack, coronary heart disease, and death from cardiovascular diseases.
Omega-3 fatty acids throughout the course of pregnancy
Omega-3 fatty acids are of significant importance for the developing fetus, and their quantity depends on the daily diet of the mother. Specialists recommend that a pregnant woman or breastfeeding mother consume greater amounts of omega-3 fatty acids, approximately 350–450 mg of DHA daily. This is particularly important during the third trimester of pregnancy, when substantial amounts of DHA accumulate in the fetal brain. DHA is crucial for the appropriate development of the brain and retina of the child. Moreover, the supplementation of omega-3 fatty acids during pregnancy can reduce the risk of premature birth. One mechanism by which EPA and DHA can reduce the frequency of premature births is by reducing the production of prostaglandins and thereby decreasing the inflammatory state in the uterus. Adhering to the due date is of great significance, as prematurity can lead to various newborn diseases and even death (M. Jarosz et al. 2020). Mothers supplementing with EPA and DHA during pregnancy and lactation can protect their children from allergies. Supplementation with fish oil is associated with a decrease in the levels of inflammatory cells and a reduced immune response (M. Jarosz et al. 2020).
Omega-3 fatty acids and their impact on fertility
Omega-3 fatty acids have positive effects on reproductive capacity. This was confirmed by the meta-analysis of B. Hosseini et al., which included randomized, controlled trials involving infertile men. It was determined that the consumption of the appropriate amounts of omega-3 fatty acids contributes to substantial enhancement of sperm motility. Moreover, omega-3 fatty acids, particularly alpha-linolenic acid, improve the quality of male sperm. In women, omega-3 fatty acids reduce the risk of developing endometriosis (M. Bojanowska and M. Kostecka 2018).
Summary of the key features of omega-3 fatty acids
Omega-3 fatty acids are an essential component of daily nutrition, providing a positive impact on the human body. They promote the development and functioning of the nervous system and vision, act as anti-inflammatory agents, and enhance the immune system. They are particularly important during pregnancy and lactation. The best sources of omega-3 fatty acids in the diet are fish and seafood. To ensure adequate intake of these nutrients, it is recommended to consume at least two servings of oily fish, such as salmon, herring, mackerel, and tuna, per week. If it is not possible to consume enough fish, it may be worth considering the use of dietary supplements.
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