Updated on 16. November 2021 from Marc Hedemann
Reading time: approx. 5 minutes
In recent years, there has been a lot of hype about omega-3 fatty acids. A growing body of scientific research now indicates that a good supply of these valuable nutrients is an essential prerequisite for health and well-being.
The following article clarifies this,
- which fatty acids are found in our food,
- why our body needs the omega-3 fatty acids EPA and DHA in particular and
- which foods you can easily cover your daily requirements with.
Fats – the controversial food components
Fatty acids and fats (lipids) are among the most problematic food components. On the one hand, they are thought to be responsible for overweight and obesity (obesity) in an ever-increasing proportion of our population. In addition, many doctors blame them for increased levels of “bad” cholesterol (LDL) and triglycerides in the blood.
When nutritionists talk about (hidden) fats in food, they mean components consisting of saturated fatty acids. Simply unsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), on the other hand, are considered healthy and should be consumed daily through unprocessed foods.1
What are omega-3 fatty acids?
Omega-3 fatty acids form a family of different long-chain biomolecules that have one thing in common: Their representatives contain either a single (monounsaturated) or multiple double bonds (polyunsaturated). What do biochemists mean by the term “unsaturated”? The easiest way to translate this word is “reactive”. In contrast to saturated fatty acids, unsaturated fatty acids easily enter into chemical reactions via their double bonds.
What is behind the term omega-3? The number 3 indicates that the first double bond starts at the 3rd carbon atom, looking from the omega end of the fatty acid molecule. For readers who want to know exactly: The last letter of the Greek alphabet omega denotes the end of the fatty acid chain furthest away from the carboxyl group (“acid moiety”).2
Which omega-3 fatty acids are found in food?
Most people are certainly familiar with the two important representatives of the omega-3 family: Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA). Both are found in varying concentrations in cold-water fish, microalgae and tiny crustaceans (krill).
Content of DHA and EPA in foods 3
|Fish (per 100 g)||DHA (mg)||EPA (mg)||Total amount (mg)|
Note: Krill oil and vegan algae oil (Schizochytrium sp., Ulkenia sp.) are commercially available in different dosage forms and concentrations of EPA and DHA.
The third generally known member of the omega-3 family is alpha-linolenic acid (ALA). It is found in larger quantities in vegetable oils such as hemp oil, linseed oil, olive oil, sunflower oil and walnut oil. There is a significant difference between omega-3 fatty acids from plant and animal sources: EPA and DHA are biologically active, but ALA is not.
What does this mean? Our organism can directly utilise biologically active compounds. ALA must first be converted into DHA and EPA by the body’s own enzymes. However, the yield is quite poor: from 100 milligrams of alpha-linolenic acid, only 5 to 10 milligrams of EPA and 2 to 5 milligrams of DHA are produced.4,5
Omega-3 and omega-6 fatty acids in the diet
In addition to omega-3 fatty acids, omega-6 fatty acids are also among the essential nutrients that we must consume in sufficient quantities through food. According to the German Nutrition Society (DGE) 2.5 percent of the total daily energy intake should be covered by omega-6 fatty acids and 0.5 percent by omega-3 fatty acids. This corresponds to an omega-6 to omega-3 ratio of 5 to 1.6
Omega-6 fatty acids are mainly found in muscle meat, offal, butter and other fats, egg yolks and vegetable oils. When listing these foods, it is not surprising that most Germans consume twice as many omega-6 fatty acids every day as the DGE recommends. Incidentally, this is the reason why many health-conscious people regularly use food supplements with omega-3 fatty acids. In this way, the ratio of omega-6 to omega-3 shifts back towards 5 to 1.
What tasks do omega-3 fatty acids perform in the human organism?
All organs of our body depend on the supply of omega-3 fatty acids. Among other things, they play a central role in the following processes:
- Production of hormones and proteins,7-9
- Production of certain cells of our immune system,10
- Cell metabolism and structure of cell membranes,11
- Regulation of triglyceride and cholesterol levels in the blood,12,13
- Control the moisture and tone of our skin.14
With a share of around 30 percent, DHA is one of the most important lipids in the brain. Among other things, it is responsible for the flexibility and permeability of the cell membranes and has a significant influence on the speed of communication between the brain cells.15
EPA and DHA are the precursors of so-called eicosanoids. The term eicanoids refers to a group of hormone-like signalling substances that regulate, among other things, fever, pain, inflammation, allergic reactions and blood clotting.16
Eicosanoids from EPA and DHA have an anti-inflammatory effect. For this reason, they can positively influence the course of autoimmune diseases such as Crohn’s disease, rheumatism (rheumatoid arthritis) and multiple sclerosis.17,18
Omega-3 fatty acid deficiency has been linked to several mental and neurological disorders. Most notably, these include autism, ADHS, depression, bipolar disorder, schizophrenia, dementia and Morbus Alzheimer.19-23
Whether omega-3 fatty acids help with cardiovascular disease is controversial among scientists. While earlier studies provided evidence of the efficacy of DHA and EPA in cardiac arrhythmias and hypertension, recent meta-analyses (comparative reviews) attribute only a minimal effect to them.24-26
What happens if there is an undersupply of EPA and DHA?
Too little omega-3 fatty acid leads to constriction of the blood vessels, increased inflammation in the body and impaired defences. The possible symptoms of an omega-3 deficiency include:27
- Muscle weakness,
- Circulatory disorders,
- Poor memory,
- Mood swings and depression,
- Dry skin.
What amounts of EPA and DHA do we need?
Unlike minerals, trace elements and vitamins, the DGE does not give reference values for omega-3 fatty acids. If you do some research on the internet, you will find information in various English-language publications. In most cases, healthy adults are recommended to consume at least 250 to 500 milligrams of EPA and DHA in their diet every day.28
But is it really enough? The actual requirement of omega-3 fatty acids depends on individual factors such as age, gender, body weight, dietary habits, sporting activities and any existing inflammations in the body. For this reason, we cannot give a blanket answer to the question of the optimal dosage. If you want to know your omega-3 status, a self-test at home is recommended.
It provides reliable information on the proportion of EPA and DHA in the total fatty acid content in the blood (Omega-3 Index) as well as the ratio of omega-6 fatty acids to omega-3 fatty acids.
The normal range is considered to be:
- Omega-3 index of at least 4 percent
- Ratio of omega-6 to omega-3 fatty acids of 5 to 1 or less
What to do if the omega-3 index and the ratio of omega-6 to omega-3 are outside the norm?
If the omega-3 self-test shows unfavourable values, it is advisable to change your dietary habits. One to two portions with a total of 300 to 700 grams of sardine, trout, salmon, herring or mackerel are enough per week for you to supply your body with 7000 milligrams of EPA and DHA. In addition, it is worth eating a colourful salad with linseed oil or hemp oil every day. This is because these vegetable oils contain omega-3 and omega-6 fatty acids in a ratio of 4:1 and 3:1 respectively.29
In order to get out of the undersupply as quickly as possible, we also recommend taking a high-quality food supplement with at least 1000 milligrams of DHA and EPA. Ideally, you will achieve an omega-3 index above 7 percent and an omega-3 to omega-6 ratio of 1:2 or even better 1:1.
Note: You do not need to fear an overdose with food supplements containing omega-3 fatty acids. According to the European Food Safety Authority (EFSA)no undesirable complications are to be expected with a daily dose of up to 5 grams of DHA and EPA.30
 Unsaturated fatty acids: This is how healthy they are!, at https://www.mylife.de, Access date 04.11.2021
 Omega-3 fatty acid, at https://www.chemie.de, Access date 04.11.2021
 Where are omega-3 fatty acids found?, at https://ak-omega-3.de, Access date 04.11.2021
 Mantzioris E et al. Dietary substitution with an alpha-linolenic acid-rich vegetable oil increases eicosapentaenoic acid concentrations in tissues. Am J Clin Nutr. 1994 Jun;59(6):1304-9.
 Brenna JT et al. Efficiency of conversion of alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Prostaglandins Leukot Essent Fatty Acids. 2009 Feb-Mar;80(2-3):85-91.
 Bold, at https://www.dge.de, Access date 04.11.2021
 Patrick RP, Ames BN. Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior. FASEB J. 2015 Jun;29(6):2207-22.
 Smith GI et al. Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr. 2011 Feb;93(2):402-12.
 Saldeen P, Saldeen T. Women and omega-3 Fatty acids. Obstet Gynecol Surv. 2004 Oct;59(10):722-30; quiz 745-6.
 Gutiérrez S et al. Effects of Omega-3 Fatty Acids on Immune Cells. Int J Mol Sci. 2019 Oct 11;20(20):5028.
 Cholewski M et al. A Comprehensive Review of Chemistry, Sources and Bioavailability of Omega-3 Fatty Acids. Nutrients. 2018 Nov 4;10(11):1662.
 Pizzini A et al. The Role of Omega-3 Fatty Acids in Reverse Cholesterol Transport: A Review. Nutrients. 2017 Oct 6;9(10):1099.
 Bradberry JC, Hilleman DE. Overview of Omega-3 Fatty Acid Therapies. P T. 2013 Nov;38(11):681-91.
 Kawamura A et al. Dietary supplementation of gamma-linolenic acid improves skin parameters in subjects with dry skin and mild atopic dermatitis. J Oleo Sci. 2011;60(12):597-607.
 Bradbury J. Docosahexaenoic Acid (DHA): An Ancient Nutrient for the Modern Human Brain. Nutrients. 2011 May;3(5):529-554.
 Eicosanoids, at https://www.chemie.de, Access date 04.11.2021
 Yan Y et al. Omega-3 fatty acids prevent inflammation and metabolic disorder through inhibition of NLRP3 inflammasome activation. Immunity. 2013 Jun 27;38(6):1154-63.
 Nutritional effects of omega-3 fatty acids, at https://www.dr-schmiedel.de, Access date 04.11.2021
 Infante M et al. Omega-3 PUFAs and vitamin D co-supplementation as a safe-effective therapeutic approach for core symptoms of autism spectrum disorder: case report and literature review. Nutr Neurosci. 2020 Oct;23(10):779-790.
 Chang JP et al. Omega-3 Polyunsaturated Fatty Acids in Youths with Attention Deficit Hyperactivity Disorder: a Systematic Review and Meta-Analysis of Clinical Trials and Biological Studies. Neuropsychopharmacology 2018 Feb;43(3):534-545.
 Messamore E, McNamara RK. Detection and treatment of omega-3 fatty acid deficiency in psychiatric practice: Rationale and implementation. Lipids Health Dis. 2016 Feb 10;15:25.
 Cardoso C et al. Dietary DHA and health: cognitive function ageing. Nutr Res Rev. 2016 Dec;29(2):281-294.
 Shinto L et al. A randomized placebo-controlled pilot trial of omega-3 fatty acids and alpha lipoic acid in Alzheimer’s disease. J Alzheimers Dis. 2014;38(1):111-20.
 Jain AP et al. Omega-3 fatty acids and cardiovascular disease. Eur Rev Med Pharmacol Sci. 2015;19(3):441-5.
 Abdelhamid AS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2018 Jul 18;7(7):CD003177.
 Abdelhamid AS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2020 Feb 29;3(3):CD003177.
 Omega-3 fatty acids, at https://www.mountsinai.org, Access date 04.11.2021
 How Much Omega-3 Should You Take per Day?, at https://www.healthline.com, Access date 04.11.2021
 Healthy Oils: How to spot a good oil – in 7 steps, at https://www.lascarabella.de, Access date 04.11.2021
 European Food Safety Authority. Scientific opinion on the tolerable upper intake level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). EFSA J. 2012;10(7):2815.