Forms of omega 3 - which is one is the best for your health and how are they different?
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It can be hard for the average consumer to tell which omega-3 supplement to choose. This article explains what omega-3 and omega-6 fatty acids actually are, why the balance between them matters, how much you need, and above all how the different forms of omega-3 differ, whether triglycerides from fish and algae, phospholipids from krill or synthetic ethyl esters, and how those differences show up in absorption and bioavailability. You will also learn which form is best avoided and why.
What will you learn in this article?
- What are omega-3 and omega-6 fatty acids?
- From nature or from the lab? How the forms of omega-3 differ
- Why cheap ethyl ester supplements can work against your health
- The three forms of omega-3 under the microscope
- Krill oil: nature's richest source of EPA
- Health benefits of omega-3 in phospholipid form
- Health benefits of omega-3 in triglyceride form
- How the form affects digestion and absorption
- Which form of omega-3 should you choose?
- The omega-6 to omega-3 ratio and why balance matters
- How much omega-3 do you need per day?
- Who should take omega-3, and who should be careful
- What are the benefits of omega-3 for the body?
- Key takeaways
What are omega-3 and omega-6 fatty acids?
Fatty acids such as omega-3 and omega-6 are chemical compounds that form an important component of the fats in our diet. A fat molecule is usually composed of the alcohol glycerol and three fatty acids. These fatty acids are monocarboxylic acids containing a long carbon chain. In omega-3 and omega-6 these are long chains of 18 to 22 carbons, between which, unlike saturated fats, there are several double bonds that give them their special properties.
Omega-3s are unsaturated fats, meaning fats with double bonds between carbon atoms. The name "omega" comes from the fact that the first double bond appears at the "omega" end of the molecule, three carbons from the end of the fatty acid chain. Omega-6s are chemically similar, with the exception that their first double carbon bond appears only at the sixth position from the end of the chain.
The cell membrane around our cells is composed precisely of fatty acids. The basic property of a semipermeable membrane is a certain fluidity and flexibility, which ensures the passage of nutrients inward and the release of unnecessary metabolites out of the cell. The degree of flexibility depends largely on what types of fat the membrane contains. If it contains a large amount of saturated fatty acids, the membrane is rigid. If it contains a balanced ratio of unsaturated omega-6 and omega-3 fats, the membrane is more fluid and flexible.
Where omega-3 and omega-6 come from in the diet
Omega-6 fatty acids are found in soy, nuts, and widely used oils and margarines. Practically all industrially processed foods contain them, which is why most of the population consumes them in excess.
By contrast, omega-3s occur much less often in the regular diet. Flaxseed oil, walnuts, chia seeds and hemp seeds contain good amounts. Fish are an excellent source, and especially wild sea fish such as salmon, tuna, mackerel or sardines. Under Central European conditions we eat very few of them.
From nature or from the lab? How the forms of omega-3 differ
Omega 3 polyunsaturated fatty acids are fats that are essential for human health. The most important omega 3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These occur naturally in two different chemical forms (triglycerides and phospholipids), which affect their absorption and bioavailability in the body. The main factor influencing the form of the fatty acids is the raw material, that is fish, algae or krill, from which the omega 3 oil is extracted.
Human intervention and laboratory modification can also produce a synthetic form of omega 3 in the form of ethyl esters that is not entirely natural to the body. The differences between the forms are therefore mainly related to their structure, which also affects how they are absorbed and used.
The production of omega 3s in their natural triglyceride (TG) and phospholipid (PL) form is based on maintaining their original form as they are commonly found in fish or marine organisms. This is also why they are more easily absorbed by the body. The process involves gentle extraction and purification procedures that minimise the use of chemical solvents.
After the fish, specifically anchovies and sardines, or sea krill are caught, the oil is extracted at low temperatures to preserve the natural properties of the omega-3 fatty acids. During purification, it is important to remove unwanted contaminants such as heavy metals, which is often achieved by molecular distillation or other physical processes without affecting the structure of triglycerides (TG) and phospholipids (PL). Thanks to the exclusive purification process of our oils, the pollutant content is close to zero. The result is an omega 3 oil in its natural triglyceride or phospholipid form that is highly bioavailable and easily absorbed by the human body.
Why cheap ethyl ester supplements can work against your health
Ethyl esters (EE), on the other hand, are synthesized industrially by binding oil from the waste parts of fish with ethanol in a process called esterification. This process produces a product that, although cheaper, is less stable and less absorbable compared to TG or PL forms.
The difference has been measured directly. In a controlled trial in 72 volunteers taking roughly 3.3 g of EPA and DHA daily for two weeks, re-esterified triglycerides reached 124% of the bioavailability of natural fish oil, while ethyl esters reached only 73%. In other words, the re-esterified triglyceride form delivered about 70% more EPA and DHA than the ethyl ester form. Free fatty acids came in at 91%, which was not significantly different from natural fish oil. [1]
In addition, the digestion of EE results in a higher production of free radicals, which may contribute to oxidative stress. The stability of the TG form ensures slower oxidation and therefore a lower risk of nutrient degradation during production and storage, contributing to better stability and shelf life.
If a person has a weak antioxidant capacity (due to chronic stress, smoking, inflammatory diseases and so on) or consumes large amounts of ethyl esters, the body may be further burdened by oxidative stress. When supplementing with omega 3, it is therefore worth choosing more stable sources in natural triglyceride or phospholipid form.
The three forms of omega-3 under the microscope
Triglycerides (TG)
Three fatty acids bound to glycerol.
More stable and less prone to oxidation.
Natural form from fish or algae.
In re-esterified form, roughly 70% better bioavailability than ethyl esters. [1]
Phospholipids (PL)
Omega 3 bound to phospholipids (PL).
Contains a phosphorus atom.
Thanks to the phospholipid structure, better integration into cell membranes.
Readily absorbed, because phospholipids mix easily with the watery contents of the gut.
Contains choline, which is a precursor of the neurotransmitter acetylcholine.
Ethyl esters (EE)
Fatty acids bound to ethyl alcohol, a bond that does not occur in nature.
Often used in concentrated and cheaper dietary supplements.
Poorer digestibility and bioavailability.
Free radical formation may occur during digestion.
May require enzymatic conversion for optimal absorption.
Not recommended.
Krill oil: nature's richest source of EPA
Unlike fish oil, krill comes from cold Antarctic waters, one of the most tightly regulated and renewable resources in the world. Its harvesting takes place under strict international oversight intended to protect ocean ecosystems and keep stocks sustainable, which is why krill oil is considered a more sustainable source of omega 3s.
Up to 90 percent of the food for juvenile krill comes from microscopic algae, primarily phytoplankton. These tiny algae are rich in nutrients, the antioxidant astaxanthin, and omega 3 fatty acids, which then accumulate in the krill body in the form of EPA and DHA. This makes these small crustaceans a suitable source of these essential fats.
Krill oil is an exceptional source of omega 3 fatty acids, especially eicosapentaenoic acid (EPA). Compared to fish oil, krill oil contains a higher proportion of EPA to DHA. EPA and DHA contribute to the normal function of the heart; the beneficial effect is obtained with a daily intake of 250 mg of EPA and DHA. The role of EPA in inflammatory processes is a subject of research, not an authorised health claim.
Another advantage of krill oil is its natural phospholipid content, which makes omega 3 fatty acids easier for the body to absorb. This has been tested head to head: in a four-week randomised trial in healthy adults, krill oil raised the omega-3 index more than fish oil did, despite delivering a lower dose of EPA and DHA. [2] Thanks to the content of the natural antioxidant astaxanthin, the fatty acids are also naturally protected from oxidation.
Health benefits of omega-3 in phospholipid form
Studies indicate that krill oil in phospholipid form is well absorbed by the body, and omega-3 bound to phospholipids is absorbed and distributed differently from the triglyceride and ethyl ester forms.
Support for cognitive function
DHA contributes to the maintenance of normal brain function; the beneficial effect is obtained with a daily intake of 250 mg of DHA. [7] Thanks to its good integration into cell membranes, the phospholipid form from krill is also being studied in connection with nerve connections and memory, but these specific effects remain a subject of research.
Preclinical work points in the same direction. In an animal study, a krill oil diet reduced markers of oxidative stress and neuroinflammation and limited memory impairment after an inflammatory challenge. [3] This is mouse data rather than a human trial, so it indicates a plausible mechanism rather than a proven clinical effect in people.
A natural part of krill oil is also choline. Choline contributes to normal lipid metabolism and to the maintenance of normal liver function [7] and is a precursor of the neurotransmitter acetylcholine.
Cardiovascular health
EPA and DHA contribute to the normal function of the heart with a daily intake of 250 mg. [7] Research also looks at the relationship between omega-3 and other cardiovascular markers, for example homocysteine levels. This is an area of research, not an authorised health claim.
Gut health and recovery
Thanks to better absorbability, omega 3 in the form of phospholipids, or triglycerides from algae, is also being studied in connection with recovery after sport and with gut health. This is an area of research, not a proven therapeutic effect.
Phospholipids at the cellular level
Better absorbability and faster transport of omega 3 into cells.
Higher proportion of EPA (eicosapentaenoic acid).
Higher bioavailability due to better integration into cell membranes. [2]
Natural content of the antioxidant astaxanthin.
Natural choline content.
Suitable for people with higher demands on the availability of omega 3, for example athletes, the elderly or people with impaired digestion.
Health benefits of omega-3 in triglyceride form
Omega 3 fatty acids in triglyceride form are well researched. Even though phospholipids have their advantages in absorbability, triglyceride forms usually deliver a higher concentration of EPA and DHA per dose.
Support for high blood triglycerides
DHA and EPA contribute to the maintenance of normal blood triglyceride levels; the beneficial effect is obtained with a daily intake of 2 g of EPA and DHA. [7] The triglyceride form from fish oil, with its higher EPA and DHA content, is therefore well suited to regular daily supplementation. You can read more in the article Dyslipidemia and elevated cholesterol.
Omega-3 and the thyroid
The relationship between omega-3 fatty acids and the thyroid is a subject of research. Studies look at their possible role in the conversion of thyroxine (T4) to triiodothyronine (T3) and at tissue sensitivity to thyroid hormones. These are not authorised health claims or a proven therapeutic effect.
Triglycerides at the cellular level
Suitable for regular daily supplementation.
Fish oil in triglyceride form often contains higher concentrations of EPA and DHA per serving compared to krill oil.
For people who need higher doses of omega 3, it may be easier to reach the desired amount with fish oil in triglyceride form.
How the form affects digestion and absorption
Omega 3 from fish in triglyceride form may be harder for some individuals to digest than krill oil in phospholipid form. People with weakened digestion, reduced production of pancreatic enzymes or reduced bile production in particular may feel an unpleasant heaviness in the stomach after taking omega 3 from fish.
Thanks to its phospholipid form, krill oil is easier to absorb, because it forms a homogeneous mixture with gastric fluids that does not burden digestion.
Phospholipids
Absorbed partially hydrolyzed or as whole molecules.
Higher bioavailability due to better integration into cell membranes.
Faster transport and more efficient use of omega 3 fatty acids in the body.
Better digestibility for individuals with fat digestion disorders.
Triglycerides
They require hydrolysis to free fatty acids for absorption.
Slower transport process into cells.
In some individuals with impaired fat digestion, absorption may be lower than with omega 3 in phospholipid form.
Which form of omega-3 should you choose?
The choice of a suitable form of omega 3 supplement should be based on the individual needs and health status of each person.
Omega 3 in the form of phospholipids from krill offers good absorption and is suited to people with specific needs, for example athletes or older people with reduced digestive capacity. The production of bile and digestive enzymes affecting fat absorption can also be reduced in some diseases of the gastrointestinal tract.
Both forms of omega 3, triglycerides and phospholipids, have their place. Phospholipids have the advantage of higher bioavailability and better integration into cell membranes. Triglycerides are widely available and well researched, which makes them a good choice for regular daily supplementation, especially when higher doses are needed. In either case, the key is to avoid the ethyl ester form.
The omega-6 to omega-3 ratio and why balance matters
Omega-6s are essential for us and must be consumed in the diet, because our body cannot synthesize them. However, one rule applies here: too much of a good thing. The main issue is maintaining the optimal ratio between the two types of unsaturated fatty acid, because this regulates the degree of inflammation in the body.
According to anthropological findings, the ratio between omega-6 and omega-3 fats in the diet of our ancestors was approximately 1:1. In current developed societies the ratio for most of the Western population ranges from about 15:1 to 16.7:1, and in some populations it is higher still. This imbalance begins to work against us because it promotes an inflammatory state, and chronic inflammation is considered one of the main contributors to most lifestyle diseases. [4]
Why do we need omega-6 at all?
Because the human body occasionally needs inflammation. It is a signal to the immune system that something unusual is happening somewhere in the body and that specific immune units need to be sent for repair. The function of vessel constriction and blood clotting is therefore important for us. Without the body's ability to aggregate platelets, we would bleed heavily even from the smallest injury. If an excess of pro-inflammatory mediators is produced, however, the body remains in a long-term inflammatory state, and that is often the basis for many pathological conditions.
One of the important functions of omega-6 and omega-3, besides their action in the cell membrane, is precisely the support of inflammatory and anti-inflammatory processes. These long-chain fatty acids form the skeleton of so-called prostaglandins and leukotrienes, and those derived from omega-6 or omega-3 differ completely in their effects. Mediators derived from omega-6 act pro-inflammatory, constrict blood vessels, and contribute more easily to thrombosis, while those derived from omega-3 have the opposite effects: they act anti-inflammatory, tend to dilate blood vessels, and reduce platelet aggregation.
Both pathways also compete for the same enzymes, and our enzymatic capacity is limited. Excessive intake of linoleic acid (LA), an omega-6, enzymatically competes with alpha-linolenic acid (ALA), an omega-3, thereby reducing its conversion into EPA and subsequently DHA, the main active derivatives of omega-3. With regular consumption of industrially processed foods, nuts and oils, and with increasing age as the conversion system becomes less efficient, we never really know how much enzymatic capacity remains for producing those anti-inflammatory metabolites. The same applies to children fed formula rich in linoleic acid.
How to reach a better ratio
Those who mainly follow a Mediterranean diet can probably balance this ratio fairly easily. In Central Europe, where the diet is based mainly on omega-6 and there is little fish on the menu (and that is before considering fish quality, freshness, processing methods or heavy metal content), we mostly remain in the ratio that supports inflammatory processes in the body. It is probably no coincidence that the most common cause of death in both women and men across Europe is cardiovascular disease.
Where omega-3s show beneficial effects, according to many studies, is in the diet of indigenous inhabitants of subarctic and arctic areas, who eat almost exclusively meat from fish, whales and seals. Their diet is based on a considerable amount of fat, of which omega-3 fatty acids make up a substantial portion and omega-6 only a small one.
How much omega-3 do you need per day?
How often do you include fish in your diet? General recommendations encourage one to two servings of oily fish per week, and EFSA advises an intake of 250 mg of EPA plus DHA per day for adults. [6] These are only approximate guides, because it cannot be universally determined how much of the active substances remains in the prepared fish after thermal processing.
There is also the question of what else fish contain. One of the greatest risks fish may hide is methylmercury. This form of mercury is formed with the help of phytoplankton bacteria and subsequently accumulates in the bodies of certain fish species. The larger and older the fish, the more it accumulates over its lifetime. Worth knowing: omega-3 supplements have not been found to contain methylmercury, because it is removed during processing. [6]
If a suitable fish source is lacking in the diet, if a fish allergy is proven, or if the diet contains a large amount of omega-6, then it is appropriate to take omega-3 regularly as a stable dietary supplement. The only reliable way to know whether you are meeting your omega-3 requirement is a blood test.
On the upper end, EFSA concluded that supplemental intakes of EPA and DHA combined at up to 5 g per day do not raise safety concerns for adults, and that long-term intakes at that level do not appear to increase the risk of spontaneous bleeding or affect glucose homeostasis, immune function or lipid peroxidation, provided the oxidative stability of the oil is guaranteed. [5] In children, pregnant and breastfeeding women, and people with health problems, the dose should be set on the basis of personal medical history, age, diet composition, medication and overall health.
Who should take omega-3, and who should be careful
Pregnant women have good reason to pay attention to omega-3 intake, because DHA is concentrated in the brain and retina and accumulates most rapidly during the third trimester, with brain accumulation continuing for roughly the first two years after birth. [6] Maternal intake of DHA contributes to the normal brain and eye development of the foetus and breastfed infants (with a daily intake of 200 mg of DHA in addition to 250 mg of DHA and EPA). [8] Fish consumption carries the methylmercury consideration described above, which is why supplements are often the more controlled route. Another group is preschool and school-age children, for whom omega-3 is supplemented with regard to the composition of their diet, which tends to be rich in omega-6.
The advantage of dietary supplements is the possibility of more precise dosing, both of the omega-3 themselves and of the ratio between EPA and DHA.
There are also situations calling for caution. People taking anticoagulant medication such as warfarin should not simply start supplementing on their own: fish oil might prolong clotting times, and the package inserts for omega-3 medicines advise that patients on anticoagulants have their INR monitored periodically, although most research indicates that 3 to 6 g of fish oil per day does not significantly affect anticoagulant status. [6] The sensible step is to agree the dose with the prescribing doctor. It is also usual to pause supplementation roughly two weeks before planned surgery.
What are the benefits of omega-3 for the body?
Omega-3 fatty acids EPA and DHA have their authorised roles in the body. EPA and DHA contribute to the normal function of the heart (with a daily intake of 250 mg), DHA contributes to the maintenance of normal brain function and normal vision (with a daily intake of 250 mg of DHA), and maternal intake of DHA contributes to the normal brain and eye development of the foetus and breastfed infants. [7] Omega-3 is also being studied in connection with inflammatory processes and immunity. Its main roles are summarized in the infographic below.
Key takeaways
The form on the label matters as much as the dose: re-esterified triglycerides reached 124% of the bioavailability of natural fish oil in a controlled trial, while ethyl esters reached only 73%.
Avoid ethyl esters: they are a cheap synthetic bond that does not occur in nature, they are less stable, and their digestion produces more free radicals.
Phospholipids from krill suit sensitive digestion: they mix readily with gastric fluids, integrate well into cell membranes, and come with natural astaxanthin and choline.
Triglycerides suit higher daily doses: fish oil in TG form generally delivers more EPA and DHA per serving, which makes it practical for regular supplementation.
Balance beats quantity: our ancestors ate roughly 1:1 omega-6 to omega-3, while the modern Western diet sits around 15:1 or higher, which pushes the body toward a constant inflammatory state.
Aim for 250 mg of EPA plus DHA a day: EFSA considers supplemental intakes of up to 5 g per day safe for adults, and a blood test is the only way to know where you actually stand.
Sources:
[1] Dyerberg J, Madsen P, Møller JM, Aardestrup I, Schmidt EB. Bioavailability of marine n-3 fatty acid formulations. Prostaglandins Leukot Essent Fatty Acids. 2010;83(3):137-141. https://doi.org/10.1016/j.plefa.2010.06.007
[2] Ramprasath VR, Eyal I, Zchut S, Jones PJH. Enhanced increase of omega-3 index in healthy individuals with response to 4-week n-3 fatty acid supplementation from krill oil versus fish oil. Lipids Health Dis. 2013;12:178. https://doi.org/10.1186/1476-511X-12-178
[3] Choi JY, Jang JS, Son DJ, et al. Antarctic Krill Oil Diet Protects against Lipopolysaccharide-Induced Oxidative Stress, Neuroinflammation and Cognitive Impairment. Int J Mol Sci. 2017;18(12):2554. https://doi.org/10.3390/ijms18122554
[4] Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med. 2008;233(6):674-688. https://doi.org/10.3181/0711-MR-311
[5] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the Tolerable Upper Intake Level of EPA, DHA and DPA. EFSA Journal. 2012;10(7):2815. https://www.efsa.europa.eu/en/efsajournal/pub/2815
[6] National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/
[7] 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
[8] Commission Regulation (EU) No 440/2011 on the authorisation and refusal of authorisation of certain health claims (maternal DHA intake and foetal brain and eye development). Official Journal of the European Union. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32011R0440
