All about omega-3 fatty acids

Written by Marina Lommel
13 minutes reading time
17. July 2023 zuletzt aktualisiert am 2. August 2023 von

I’m sure you’ve heard about the importance of omega-3 fatty acids, perhaps pay attention to eating fatty sea fish or even take fish oil capsules. But why exactly are omega-3 fatty acids relevant for the body? At what point in the metabolism do they come into play? And is it true that omega-3 fatty acids can increase fat burning?

We want to clarify these questions in this article.

Table of contents

    1. what are omega-3 fatty acids?

    Omega-3 fatty acids are so-called essential fatty acids. This means that our human metabolism cannot produce them itself and they must therefore be ingested with food. Omega-3 fatty acids belong to the group of unsaturated fatty acids.

    The most important omega-3 fatty acids include α-linolenic acid, docosahexaenoic acid (DHA for short) and eicosapentaenoic acid (EPA for short).

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    2. why are omega-3 fatty acids so important?

    Omega-3 fatty acids are an important component of the cell membrane. The cell membranes of the brain and the retina in the eye have a particularly high content of omega-3 fatty acids. This explains the importance of omega-3 fatty acids for brain development and vision.

    • Important for healthy brain development
    • Important for good vision

    Omega-3 fatty acids have an impact on blood lipid levels and the risk of cardiovascular disease (heart disease).

    • Reduce the risk of cardiovascular disease
    • DHA and EPA lower triglyceride levels
    • Can reduce the risk of stroke
    • Promote blood circulation
    • Lower blood pressure

    There is evidence that omega-3 fatty acids reduce the risk of prostate cancer, colorectal cancer and breast cancer and are protective.

    • Possibly lower the risk of cancer

    A positive influence in Alzheimer’s disease and other neurodegenerative diseases is also discussed.

    • May reduce the risk of Alzheimer’s disease and other neurodegenerative diseases

    Omega-3 fatty acids have an anti-inflammatory effect, while omega-6 fatty acids have a pro-inflammatory effect. We consider the exact mechanisms under point 6. For this reason, omega-3 fatty acids can have a positive effect on autoimmune diseases by reducing pro-inflammatory messenger substances.

    • Act anti-inflammatory (anti-inflammatory)
    • Can reduce pro-inflammatory messenger substances (mediators)
    • May have a positive influence in autoimmune diseases

    Omega-3 fatty acids also seem to have an influence on the human psyche. Thus, a low omega-3 index is a risk factor for future suicide attempts. Omega-3 index is a parameter that indicates the content of DHA and EPA in red blood cells. Individuals with lower omega-3 intakes are more likely to experience depression and bipolar disorder. The fatty acid EPA appears to have an antidepressant effect. Individuals suffering from schizophrenia, as well as adolescents and adults with attention-deficit/hyperactivity disorder, have lower omega-3 levels than healthy controls.

    • Likely to lower risk for depression and bipolar disorder
    • Possibly lower aggression potential in borderline personalities.
    • Increase the dopamine available in the brain

    In ADHD, omega-3 fatty acids act in the same way as classic medications by increasing the availability of dopamine in the brain.

    Some studies indicate improved protein synthesis from adequate omega-3 intake. Protein synthesis is the building of proteins from amino acids (from food), i.e. muscle building.

    • Probably support muscle building in athletes
    • Probably protect against muscle loss due to lack of exercise, illness and old age

    Possibly this effect arises from an increase in testosterone concentration, which in turn promotes muscle building

    3. how do omega-3 fatty acids differ from other fatty acids?

    Basically, there are 3 subtypes of fatty acids – depending on their chemical structure: saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids.

    Each fatty acid consists of a long strand of carbon atoms (C). Like humans, the carbon atom can hold on to other atoms with its “arms”. It can make a total of 4 bonds – so imagine the carbon atom has four arms. It is only through these bonds that larger linkages of atoms, called molecules, are formed.

    For a fatty acid, a lot of carbon atoms hold on to each other, forming a long chain. Each carbon atom then still has two arms free. Atom children come running and hold on to the free arms so as not to be alone. These are the hydrogen atoms. Everyone dances hand in hand across the village square.

    Thus, each carbon atom has another carbon atom on two arms and a hydrogen atom on two arms. If no arm remains free, the fatty acid is saturated. Every arm is occupied, every possible binding is used.

    But now two children go home earlier – that means two hydrogen atoms separate from the community. Therefore, two carbon atoms now each have one arm free. Imagine these two are right next to each other. They give each other the two free arms and hold hands. So now there is a double bond between these two atoms. The fatty acid is unsaturated because not every carbon atom has two hydrogen atoms with it.

    Where the two carbon atoms shake hands twice, the row moves differently. Here the dance is a bit more rigid, there is a kink in the long line.

    More hydrogen children go home and more carbon atoms shake hands. Thus, several double bonds are formed in our long fatty acid. As soon as there is more than one double bond, one speaks of a polyunsaturated fatty acid. At each point where there is a double bond, the row gets a kink.

    Omega-3 fatty acids are polyunsaturated fatty acids in which the double bond is in a very specific location.

    4. where do omega-3 fatty acids occur?

    Omega-3 fatty acids are found in animal and plant foods. The α-linolenic acid is found almost exclusively in plant sources, the docosahexaenoic acid (DHA) and the eicosapentaenoic acid (EPA) in animal sources.

    The best sources of DHA and EPA are fatty sea fish, such as salmon, mackerel, herring, tuna and sardine. Vegetable sources are hemp oil, rapeseed oil, linseed oil and soybean oil. Why soybean oil and canola oil, for example, are nevertheless less suitable as omega-3 sources, we discuss below.

    Butter and the fat from beef are also sources of omega-3 fatty acids. A higher omega-3 content is found in milk and fat from grazing animals compared to grain-fed animals.

    In this table you can see the omega-3 fatty acid content of different fat sources:

    Fatty acid compositions of various oils and fat sources

    Fat source saturated fatty acids Monounsaturated fatty acids polyunsaturated fatty acids omega-3 polyunsaturated fatty acids omega-6
    Olive oil 12,0% 78,0% 1,0% 9,0%
    Safflower oil 9,0% 14,0% 0,3% 76,7%
    Rapeseed oil 8,0% 65,0% 8,0% 19,0%
    Linseed oil 8,3% 19,0% 58,0% 14,7%
    Walnut oil 8,9% 17,0% 12,8% 61,3%
    Soybean oil 15,0% 22,0% 7,7% 52,9%
    Grape seed oil 12,0% 12,0% 0,4% 75,6%
    Corn oil 13,0% 34,0% 1,0% 55,5%
    Sunflower oil 12,0% 24,8% 0,2% 63,0%
    Hemp oil 10,0% 12,8% 21,2% 56,0%
    Avocado 2,8% 8,1%% 1,7% 0,2%

    5. How much omega-3 fatty acids do I need?

    Official institutions such as the EFSA (European Food Safety Authority) or the DGE (German Nutrition Society) recommend 250 mg of omega-3 fatty acids per day, which should come from DHA and/or EPA. Why these omega-3 fatty acids from animal sources are more valuable for the body than α-linolenic acid, we clarify under point 8. Pregnant women and children have an increased need. The reason is the important influence of omega-3 fatty acids on the development of the brain and nervous system. For the neuronal development of the embryo, pregnant women and also women of childbearing potential should consume an additional 100-150 mg of DHA and/or EPA, for a total of 350-400 mg per day.

    A voluntary higher intake of omega-3 fatty acids is often used by athletes interested in increased fat burning.

    6. why is the omega-6/ omega-3 ratio important?

    Omega-3 fatty acids have an anti-inflammatory effect, while omega-6 fatty acids tend to have the opposite effect: They promote inflammatory messengers. Nevertheless, omega-6 fatty acids are also important for the body because they promote growth, wound healing and defense against infectious agents.

    Our current diet is high in pro-inflammatory omega-6 fatty acids due to high consumption of vegetable oils and grain-fed meats. We consume about 8 to 15 times as much omega-6 fatty acids as omega-3 fatty acids in a “normal” diet.

    In many studies, a ratio of 4 to 1, i.e. only four times as many omega-6 fatty acids, has been judged desirable. This ratio is called the omega-6/omega-3 ratio.

    The influence of omega-3 and omega-6 fatty acids on inflammatory messengers arises from their interplay with certain hormone-like messengers (mediators) called eicosanoids. Eicosanoids include prostaglandins, which promote inflammation. They are also relevant for a functioning pain sensation and blood clotting. From this you can see that it never makes sense to completely “turn on” or “turn off” something. If all inflammatory mechanisms were stopped, we would have neither a functioning immune system nor a functioning blood clotting system. The right dose is the key.

    In the body, omega-3 and omega-6 fatty acids compete for the same enzymes. Too much omega-6 takes “space” away from omega-3 and vice versa. However, since our foods are much richer in omega-6, there is little need to worry about “too little” omega-6 fatty acids.

    Omega-3 fatty acids have an anti-inflammatory effect in interaction with the above-mentioned messenger substances, as they lower the concentration of arachidonic acid, for example. Arachidonic acid is a precursor for a pro-inflammatory messenger substance. Omega-3 fatty acids also reduce the concentration of free radicals (reactive oxygen species, ROS for short) in cells of the immune system. These are important in the invasion of pathogens, because these ROS are virtually the projectile of our immune defense cells. They kill intruders. ROS are a very dangerous ammunition, therefore it is important that the immune system calms down after repelling the invaders.

    7. do omega-3 fatty acids promote fat burning?

    Almost every fitness brand that offers protein powders and other supplements also has omega-3 fatty acids in its lineup. In (almost) every “fat burner” preparation, they are included. But, is there anything to it? Yes!

    The effect is mediated via so-called PPARs (pronounced pipar, just think of Pippa Middleton). Their full name is peroxisome proliferator-activated receptors. They are located in the cell and are activated by various substances. Subsequently, they regulate the switching on and off of certain genes.

    If a special type of PPAR – PPARα – is used, it coordinates the switching on and off of genes in such a way that blood fat levels change and fat metabolism increases. The uptake of fatty acids into the tissues increases, where subsequently the combustion of fatty acids, i.e. fatty acid oxidation increases.

    The concentration of triglycerides in the blood as far as the concentration of LDL cholesterol decreases, while that of (positive) HDL cholesterol increases. [Side note: You can never remember which is the “positive” cholesterol? Just read HDL as a chat abbreviation. “Love you”] The PPAR subtype PPARγ also has a positive effect on metabolism. When this receptor is activated, insulin sensitivity is increased and glucose metabolism is improved.

    Also PPAR-β/δ has influence on lipid metabolism and effect on metabolism of glucose and cholesterol.
    Now comes the crucial point: the receptors are activated by a special substance (a ligand) binding to them. Several substances can activate these receptors, which is why intensive research is being conducted into drugs that follow this path.

    An all-natural activator of PPARα is the omega-3 fatty acid EPA, and the omega-3 fatty acid DHA in turn activates PPARγ.

    8. omega-3 from animal or plant source?

    The omega-3 fatty acid α-linolenic acid comes from plant foods, while docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) come from animal foods. In purely theoretical terms, DHA and EPA are not essential, because both can be converted from α-linolenic acid by the body.

    However, the conversion rate is not particularly high – not the complete amount of ingested α-linolenic acid can be converted into DHA or EPA. Data on conversion rates, depending on the study, range from 5% EPA and less than 0.5% for DHA, or even 6% for EPA and 3.8% for DHA. Even though these figures fluctuate greatly, they are always very low.
    A high intake of omega-6 fatty acids further lowers the conversion rate.

    This fact is relevant because not all omega-3 fatty acids have the same effect. Thus, it has already become clear in the section on lipid metabolism and PPARs that DHA and EPA activate different receptors.

    While DHA and EPA lower triglyceride levels, α-linolenic acid seems to increase them rather. While DHA has a positive effect on blood pressure, i.e. it lowers blood pressure, α-linolenic acid does not have this property. Many experts therefore recommend the intake of omega-3 fatty acids primarily from animal sources such as fatty sea fish or supplementation with fish oil.

    Although the vegetable linseed oil has a high content of omega-3 fatty acids, it should not be the only source (and not the main source), because it contains α-linolenic acid instead of DHA and EPA.

    With vegetable oils such as linseed oil, it should also be noted that they should be stored in a dark and cool place and not kept open for too long so that the fatty acids do not oxidize. Unfortunately, these oils often oxidize during production, which is why we always emphasize the intake of omega-3 fatty acids from animal sources in our recommendations.

    But omega-3 fatty acids in fish can also be damaged if it is cooked too hot or too long. A fine salmon with a pink core, not dry but nice and juicy would be ideal – or even better raw fish in the form of sashimi, for example.

    9. which supplements are suitable - and do I need them?

    If you eat fatty sea fish at least 1-2 times a week and also use valuable nuts and seeds as well as high-quality oils from time to time, you should be well supplied.

    When we talk about a serving of fatty sea fish, we are definitely talking about a salmon fillet, for example, not the mini piece of salmon in a sushi roll. The quality of the fish is definitely important here – cheap aquaculture with antiobiotic feeding is a no go – for the environment and your health. Seek fish from organic aquaculture or sustainable wild catch.

    If you’re not much of a fish eater or just don’t get a good piece often enough, you should definitely consider supplementation. Omega-3 fatty acids hold such diverse and important functions in the body that a deficiency can offer a significant break in health and well-being.

    As mentioned above, especially for pregnant women, women of childbearing potential and children, a sufficient supply is important to cover the increased need.

    There are the following points to consider when choosing the right supplement:

    • No cheap stuff from the drugstore. In addition to unnecessary plastic blisters, the capsules’ shells are often made of low-quality material.
    • No unnecessary additives or fillers.
    • Sufficient concentration for 250 mg DHA/EPA per daily dose.
    • Sustainable catch of the fish or crabs (for krill oil).

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    You have questions about the topic or suggestions for new articles? Feel free to leave us a comment, we look forward to hearing what you think.

    Sources and reading material:

    Bourre JM. 2004. Roles of unsaturated fatty acids (especially omega-3 fatty acids) in the brain at various ages and during aging. J Nutr Health Aging, 8(3):163-74.

    Ewaschuk JB1, Almasud A, Mazurak VC. 2014.Role of n-3 fatty acids in muscle loss and myosteatosis. ,Appl Physiol Nutr Metab, 39(6):654-62.

    Simopoulos AP. 2002. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother, 56(8):365-79.

    Smith GI, Atherton P, Reeds DN, Mohammed BS, Rankin D, Rennie MJ, Mittendorfer B. 2011. Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr, 93(2):402-12.

    Tyagi S, Gupta P, Saini AS, Kaushal C, Sharma S. 2011. The peroxisome proliferator-activated receptor: A family of nuclear receptors role in various diseases. Journal of Advanced Pharmaceutical Technology & Research, 2(4):236-240.

    Internet pages:

    This article was written by

    Marina Lommel

    Marina gründete Foodpunk nach ihrem Abschluss in Ernährungswissenschaften und ist aktuell CEO des Unternehmens. Während ihres Studiums arbeitete sie in verschiedenen Bereichen, darunter in der Wissenschaftsredaktion beim Radio, Redaktion beim TV und Uni-Wissensmagazin sowie im Labor am DZNE in der Parkinsonforschung. Marina ist außerdem Autorin von 5 ernährungswissenschaftlichen Sachbüchern.

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