Author: Rositsa Tashkova, Master of Molecular Biology and Microbiology

omega-3 in fish

In recent years, omega-3 fatty acids have gained huge popularity due to their numerous health benefits. They are widespread in nature, being an important part of lipid metabolism of animals and playing a significant role in human health.

The three types of omega-3 fatty acids involved in human physiology are α-linolenic acid (ALA), which is of plant origin, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) - well known as fish oil.

It is curious that fish do not actually produce omega-3 fatty acids, but instead accumulate them in their body by consuming either microalgae or prey that has accumulated omega-3 fatty acids itself.

But for the same reason these fish also accumulate larger amounts of heavy metals (mercury), and this is the reason why they are not recommended for pregnant women and nursing mothers, although it is for them that omega-3 fatty acids are of particular importance.


Omega-3 fatty are important for children's brain development

Omega-3 and omega-6 fatty acids are the main polyunsaturated fatty acids that play a central role in brain development.

omega-3 for children's mental development

The accumulation of omega-3 fatty acids in the brain occurs during intrauterine development and until the age of 3, and then accumulated high levels persist throughout life.

The accumulation of omega-3 fatty acids in cell membranes contributes to enhanced information processing and thus to better problem-solving ability, increased attention of children and improved mental abilities.

Unfortunately, insufficient intake of omega-3 fatty acids leads to brain damage. Inadequate or unbalanced intake of fatty acids can lead to nervous development disorders such as attention deficit hyperactivity syndrome (ADHD), dyslexia and autism spectrum disorders.

Read more in the article Which foods boost children's brain development since conception [ref.1].


Omega-3 fatty acids and the immune system

According to a 2010 study, [ref.2], the intake of fish oil from pregnant women is associated with immunological changes in umbilical cord blood and can suppress the appearance of sensitivity to common food allergens and reduce the frequency and severity of atopic dermatitis in the first year of life.

omega-3 for the immune system

According to scientists, this effect can last until adolescence with a decrease in the appearance or severity of eczema, hay fever and asthma. Taking fish oil in early childhood can reduce the risk of developing some allergies.

Moreover, studies show that getting enough omega-3 in the first year of life is associated with a reduced risk of developing many autoimmune diseases, including type 1 diabetes, autoimmune diabetes and multiple sclerosis.

Read more about autoimmune diseases in the article Herbs for autoimmune disease sufferers and transplant patients.


Omega-3 fatty acids for healthy skin and shiny hair

Omega-3 fatty acids, and in particular those of animal origin (EPA and DHA) are important for preserving the vitality of the skin, its hydration, slowing down the appearance of wrinkles, exerting some protection from the harmful influence of the sun, suppressing inflammation and fighting acne.

Omega-3 deficiency can lead to dry, flaky skin and dandruff.

Balanced intake of omega-3 fatty acids has a beneficial effect on the structure of hair follicles and sebaceous glands. Eating foods that contain a lot of omega-3 can improve the health of the scalp and strengthen the hair.

omega-3s are good for hair and skin


Omega-3 fatty for multiple sclerosis sufferers

According to a 2019 overview [ref.3], omega-3 and fish oil supplements (EPA, DPA and DHA) have beneficial effects on reducing relapse rates, inflammatory markers and improving the quality of life of patients with multiple sclerosis.

In 2013, a study was conducted among more than 2,400 patients with multiple sclerosis who were asked to provide information about: MS type, relapse rate, impairment, quality of life, fish consumption rate and omega-3 supplements, including type and dose. Those who consumed fish more frequently and those who took omega-3 supplements had significantly better quality of life and fewer disabilities.

Greater fish consumption was noticeably associated with a better condition of multiple sclerosis sufferers. There is also a tendency to less frequent recurrences and reduced activity of the disease. The addition of linseed oil was also associated with more than 60% lower recurrence rates in the previous 12 months. [ref.5]

omega-3 against autoimmune diseases


Omega-3 fatty acids' anti-inflammatory effect may help autoimmune disease sufferers

Among fatty acids, it is omega-3 polyunsaturated fatty acids that possess the most powerful immunomodulating properties, and among the types of omega-3s, those in fish oil (EPA and DHA), are more powerful from a biological point of view than alpha-linolic acid (ALA), which has a plant origin.

Omega-3 fatty acids have anti-inflammatory properties and can therefore be useful in the treatment of inflammatory and autoimmune diseases. Ischemic heart disease, severe depression, aging and cancer are characterized by an increased level of interleukin-1 (IL-1) - cytokine, which provokes inflammation.

Similarly, arthritis, Crohn's disease , ulcerative colitis and lupus erythematosus are autoimmune diseases, characterized by a high level of IL-1 and pro-inflammatory leukotriene 4 (LTB4).

There are a number of clinical trials evaluating the benefits of dietary fish oil supplements in some inflammatory and autoimmune diseases in humans, including rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, lupus erythematosus, multiple sclerosis and migraine headaches.

Many of the placebo-controlled studies of fish oil in chronic inflammatory diseases reveal a significant benefit, including reduced activity of the disease and reduced need to use anti-inflammatory drugs. [ref.4]

omega-3 anti-depression


Omega-3 fatty acids may help against depression and other psychiatric illnesses

Some studies support the thesis that taking omega-3 fatty acids, especially EPA and DHA, has a protective effect in mood disorders such as depression and bipolar disorder.

The benefit of single-polar and bipolar depression is statistically significant. There is less evidence of the benefit of omega-3 for schizophrenia sufferers.

The health benefits of omega-3 fatty acids can be especially important for patients with mental disorders, since they are more often heavy smokers and suffer from obesity, as well as negative side effects on metabolism by some psychotropic drugs. [ref.6]


Omega-3 may reduce cancer risk

Some studies have shown that people who consume a lot of omega-3 have up to a 55% lower risk of colorectal cancer [ref.7], as well as a reduced risk of prostate cancer in men and breast cancer in women.

omega-3 in yogurt


Other benefits of omega-3 fatty acids

Many more benefits of omega-3 fatty acid intake have been identified. Here we will only mention them:

  • May improve mental state as you get older and in Alzheimer's disease;
  • May reduce the symptoms of metabolic syndrome;
  • May reduce the symptoms of children with attention deficit hyperactivity disorder;
  • May lower the risk of cardiovascular disease;
  • May improve eye health;
  • May help against asthma in children;
  • May improve bone and joint health;
  • They can improve sleep.

omega-3 fatty acids in fish

Foods that contain the most omega-3 fatty acids

Foods of animal origin that are rich in omega-3 fatty acids (EPA, DHA per 100 g product) are:

  • Salmon: 4.0 grams EPA and DHA;
  • Mackerel: 3.0 grams EPA and DHA;
  • Sardines: 2.2 grams EPA and DHA;
  • Anchovies: 1.0 grams EPA and DHA;
  • Cod liver fish oil - available in the form of capsules with different omega-3 content;
  • Yogurt.

Concerns about mercury shouldn't stop you from eating fish - or taking fish oil supplements.

omega-3 fish oil dietary supplement

The presence of mercury in fish is not a problem unless you are pregnant or breast-feeding. In these cases, you can choose fish with low mercury content and high omega-3 content, such as: salmon, sardines, trout and canned tuna.

Foods of plant origin that are rich in omega-3 fatty acids (ALA per 100 g product) are:

  • Linseed (flaxseed): 22.8 grams ALA;
  • Hemp seed: 9.3 grams ALA, contains omega-3 and omega-6 in optimal ratio;
  • Walnuts: 9 grams ALA;
  • Perilla oil - 1 tbsp contains about 9 grams of ALA;
  • Chia seeds: 5.8 grams ALA;
  • Brussels sprouts: 100 mg ALA;
  • Algae oil: available in the form of soft gel capsules, which usually contain 400–500 mg of DHA and EPA. The daily recommended dose of DHA+EPA is 300–900 mg.

omega-3 in nuts

It is good to keep in mind that ALA are not so active in the body and in order to have the same health benefits, they should be converted into the two other forms of omega-3 fatty acids - eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Unfortunately, the body's ability to convert ALA into EPA and DHA is limited. Only about 5% of ALA is converted into EPA, while less than 0.5% is converted into DHA.

Moreover, the omega-6 to omega-3 ratio in the body is also very important, since a diet low in omega-3, but high in omega-6 can increase inflammation and the risk of disease.


Omega-3 fatty acids have many health benefits, and the most suitable way to obtain them is through regular consumption of delicious fish, seafood, walnuts, linseed. Balanced and varied nutrition is the best medicine.



  1. Food for good mental development of children since conception,, 2020
  2. Is there a role for fatty acids in early life programming of the immune system? , 2010, Proceedings of the Nutrition Society
  3. Effect of omega-3 fatty acids and fish oil supplementation on multiple sclerosis: a systematic review, 2019, Nutritional Neuroscience
  4. Omega-3 fatty acids in inflammation and autoimmune diseases, 2002, J Am Coll Nutr
  5. Association of fish consumption and Ω 3 supplementation with quality of life, disability and disease activity in an international cohort of people with multiple sclerosis, 2013, International Journal of Neuroscience
  6. Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry, 2006, Journal of Clinical Psychiatry
  7. Dietary fatty acids and colorectal cancer: a case-control study, 2007, American Journal of Epidemiology


The author:

👩 🔬 Rositsa Tashkova-Kacharova has a Bachelor degree in Molecular Biology and a Master's degree in Microbiology and Microbiological Control. She completed her Master's thesis at the University of Nantes, France. At that time she painted a Christmas tree of bacteria and inspired the announcement of the first competition for drawing with microorganisms Agar Art. For 3 years she was the editor of the journal Bulgarian Science and continues to write about science and medicine.