The omega 3 in fish is made by microalgae: EPA and DHA are born in plankton, then pass from one link of the food chain to the next. A vegan omega 3 can therefore come from the source itself, microalgae oil, whereas flax or walnuts mainly provide ALA. Sources double-checked with my eye as an ISTOM engineer, as the founder of Biovie.
21 November is World Fisheries Day. I'm taking the occasion to ask an almost naive question: where does salmon get its omega 3? Not from itself, believe it or not. Let's follow the supply chain upstream together, then look honestly at what each vegan omega 3 source gives you on a vegan diet, from flaxseed to microalgae oil.
Fish don't make their own omega 3: they owe it to microalgae
Vegan since 1992, I've got used to looking at what I eat as a supply chain, from the field or the sea all the way to the plate. It's also my job: at Biovie, since 2007, I trace products back to whoever produces them. With omega 3 as a vegan, the exercise holds a nice surprise.
EPA and DHA, the two so-called "long-chain" omega 3s, are not a fish invention. They are produced in large quantities by certain microalgae, those microscopic organisms that form the base of plankton (Gladyshev et al., 2013). What follows is a matter of menu: zooplankton eat them, small fish eat the zooplankton, oily fish eat the small ones. At each step, EPA and DHA pass to the next link and concentrate there, more efficiently than the rest of the carbon in the chain. Humans, like most omnivores, depend on this dietary supply.
Salmon, basically, is the corner grocer. It sells omega 3 made by others: its prey got them from plankton themselves. But when you're looking for a plant-based omega 3, the question becomes very simple: why not go straight to the producer?
What the FAO says in 2026
The grocer's shelf, though, has changed a lot. According to the 2026 FAO report, production of aquatic animals reached 195 million tonnes in 2024, of which 103 million came from aquaculture. That's 53%, a first. More than one tonne in two of the aquatic animals produced worldwide now comes from a farm. Wild-caught fish, the kind we celebrate on that day, is no longer the majority.
On the sea side, the news is more mixed. In 2023, 62.4% of stocks were fished at a biologically sustainable level, down from 64.5% in 2021: a little under two in three. Measured by volume, however, 72.6% of the landings assessed in 2023 come from sustainable stocks, nearly three tonnes out of four.
Two figures, two stories? Not really. One counts stocks, the other counts tonnes, and the big stocks are better managed. The FAO also attributes part of the decline to a revision of its assessment methods, which is a reason to read these figures with caution in both directions. So I'll stop there: no looming catastrophe, and no reason for easy reassurance either.
Vegan omega 3 or animal omega 3: what is the difference between ALA, EPA and DHA?
The plant omega 3 found in seeds and oils is ALA; fish and microalgae provide EPA and DHA, two long-chain omega 3s. The body converts little ALA into EPA and very little into DHA: the two families are therefore not interchangeable.
I picture this "long chain" business as a string of carbon beads: ALA has 18, EPA 20 and DHA 22. Two more beads seems like very little. Yet lengthening that string takes the body a whole workshop's worth of work, and that workshop doesn't run at full capacity.
The ANSES reference values for adults are daily ones: ALA at 1% of energy intake, or about 2.2 g a day for 2,000 kcal, then 250 mg of DHA and 250 mg of EPA. A quarter of a gram is roughly the weight of a pinch of salt. For its part, EFSA sets 250 mg a day of EPA and DHA combined. ANSES counts EPA and DHA separately, EFSA adds them up: the two opinions therefore don't contradict each other.
| Omega 3 | Where to find it | Daily reference value, adults (ANSES) |
|---|---|---|
| ALA (18 carbons) | Seeds and oils of flax, camelina, hemp, rapeseed; walnuts | 1% of energy intake, about 2.2 g |
| EPA (20 carbons) | Oily fish, microalgae, dulse in small amounts | 250 mg |
| DHA (22 carbons) | Oily fish, microalgae | 250 mg |
So plant-based DHA does exist: it comes from microalgae. You still have to go and get it.
Does the body convert ALA into EPA and DHA?
That's the whole question: if you eat enough ALA, will the body do the rest? To find out, researchers have people swallow ALA labelled with carbon 13, a stable form of carbon, then follow its trail in the blood, the way you track a parcel by its number. The percentages below are therefore not back-of-the-envelope estimates: they are measured.
In adult men, about 8% of ALA is converted into EPA, and less than 0.1% into DHA (Williams and Burdge, 2006). Out of a hundred ALA molecules swallowed, eight become EPA; for DHA, it's fewer than one in a thousand. Fewer than one in a thousand! Counting on that path alone for your DHA is a bit like filling a bathtub with a teaspoon.
In young women, the picture changes markedly. A tracer study (700 mg of labelled ALA, followed over 21 days) measured a net conversion of 21% into EPA, 6% into DPA, an intermediate omega 3, and 9% into DHA (Burdge and Wootton, 2002). In them, ALA goes markedly further. One explanation has been put forward: the effect of estrogens (Burdge and Calder, 2005).
The same study offers a lesser-known detail: about 22% of the labelled ALA is burned for energy and found in exhaled air within the first 24 hours. A good share of ALA serves as fuel before it has even had the chance to lengthen. You swallow it to thread more beads, and the body throws part of it into the furnace.
On the big seaweed articles of this blog, I spent days and days looking for studies to back up every statement. So the "less than 15%" that circulates online makes me frown: it's a figure with no source and no scope, whereas measurements vary with sex and method. ALA conversion exists, but it remains limited, especially towards DHA, which ANSES considers impossible to synthesise in sufficient quantity, even from an ALA intake.
What each plant source provides, and its limits
Not all sources of vegan omega 3 play in the same league. Each has its place, as long as you know what you're asking of it.
Seeds and oils: flax, camelina, hemp, walnuts
Flax, camelina, hemp and walnuts, not forgetting rapeseed, provide ALA. For this fatty acid, European regulation authorises a specific claim: "Alpha-linolenic acid contributes to the maintenance of normal blood cholesterol levels". The beneficial effect is obtained with a daily intake of 2 g of ALA (Regulation (EU) No 432/2012), as part of a varied and balanced diet and a healthy lifestyle. Two grams is less than the weight of a sugar cube.
The amounts vary from one seed to another: you'll find them in our article on the omega 3 composition of flaxseed oil, and in our guide to vegetable oils and seeds rich in omega 3. It is to this ALA that flaxseed oil owes its recognised benefit as a plant omega 3. Simply, it is neither EPA nor DHA.
Seaweed: the example of dulse
Dulse, that red seaweed of the Atlantic coasts, has a fatty acid profile that sounds dreamy on paper: in a dulse farmed in Portugal, EPA makes up about 52% of the identified fatty acids (Lopes et al., 2019). The catch is that its lipids weigh only about 1% of its dry weight.
In other words, in a handful of dried dulse, the fat is counted in crumbs: top-quality EPA, but in small quantity. A grand cru served by the teaspoon, in short.
Dulse therefore provides a little EPA as a complement; to replace fish in quantity, it falls far short. An honest caveat: these values concern a Portuguese sample analysed in a laboratory, not necessarily a Breton dulse. To dig deeper, we devoted a whole article to dulse and its EPA.
Microalgae oil: going back to the source
What remains is the most direct route: fetching EPA and DHA from those who make them. In a two-week randomised trial in 32 adults, a microalgae oil and cooked salmon, each providing 600 mg of DHA a day, raised DHA equivalently (Arterburn et al., 2008): about +80% in plasma phospholipids, +25% in red blood cells.
The DHA from microalgae oil was as well absorbed as the DHA from fish. After a fortnight, the blood of both groups told the same story. Let's still keep a cool head: the study, run open-label on a small group, measured blood DHA levels, without assessing any effect on health or on EPA.
Biovie doesn't sell any yet, I should say, but it's the simplest way to find plant-based EPA and DHA.
On your plate: getting vegan omega 3 without fish
Everyone at their own pace, of course. The idea is to add a few habits to what you already do, without upending anything. Here are the ones that take the least effort, and no equipment:
- a drizzle of flaxseed or camelina oil, raw, on a salad or vegetables just before serving;
- flaxseeds ground just before use, over fresh fruit or a morning compote;
- a handful of walnuts;
- dulse flakes, or rehydrated dulse, raw on a salad or added off the heat to a soup, never pan-fried or sautéed.
As for EPA and DHA, whatever their origin, Regulation (EU) No 432/2012 authorises these wordings: "Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contribute to the normal function of the heart", for 250 mg of EPA and DHA a day; "Docosahexaenoic acid (DHA) contributes to the maintenance of normal brain function" and "Docosahexaenoic acid (DHA) contributes to the maintenance of normal vision", for 250 mg of DHA a day. These claims relate to the nutrients themselves, at the stated doses, as part of a varied and balanced diet and a healthy lifestyle.
Storing seeds and oils
Omega 3s are fragile fats that don't cope well with air and light. Keep your flaxseed oil cool and away from light, and grind your seeds as you go, the way you grind coffee (for that, use a mini blender, the kind you easily find in a shop like Action, for example).
I know a thing or two about this. At one point, we stored up to 25 kilos of walnuts and almonds under the sofas, in duvet storage bags vacuum-sealed with the vacuum cleaner. Not a good idea, between rancidity and rodents! Today, we store 5 kilos at a time.
For seeds and nuts, we recommend at Biovie vacuum-sealing in glass jars with the BocUp kit: a bell and a small hand pump, no electricity and no plastic bag. It works with the glass jars you already have at home, if they have "shoulders" and a 65 or 84 mm lid. According to the manufacturer, dry foods stay protected from moisture and moths, and fresh products keep up to 5 times longer (a vegetable soup, 8 to 10 days instead of 2).
Vacuum-sealing doesn't replace the fridge or the freezer, and it doesn't sterilise. For the details, here are the benefits of vacuum-sealing at home.
This 21 November, I find it delightful to remember that the smallest inhabitant of the sea makes what we go looking for in fish. All it took was to follow the supply chain upstream and watch nature: it's simply common sense. Let's hope that in a few years, people will think of microalgae before fish when they talk about omega 3. A drizzle of flaxseed oil on your next salad will make a very good first step. And if you have your own tricks for slipping some onto the plate, write to me!
Frequently asked questions
What are the benefits of vegan omega 3?
Alpha-linolenic acid (ALA), the omega 3 of seeds and some vegetable oils, contributes to the maintenance of normal blood cholesterol levels: this is the claim authorised by European Regulation 432/2012, for a daily intake of 2 g of ALA, as part of a varied and balanced diet and a healthy lifestyle. Flax, camelina, hemp and walnuts contain it.
Plant or animal omega 3: which should you choose?
It all depends on which omega 3 you are after: seeds and some vegetable oils provide ALA, fish and microalgae provide EPA and DHA. The body converts about 8% of ALA into EPA in adult men, 21% in young women in one study, and far less into DHA: the two families complement each other.
Where can you find EPA and DHA without eating fish?
In microalgae, which make the EPA and DHA that fish then accumulate. Microalgae oil is the most direct form: in a trial in 32 adults, its DHA was absorbed like that of cooked salmon. Dulse provides a little EPA, its lipids weighing only about 1% of its dry weight.
Is algal oil as effective as fish?
Yes for blood DHA, according to a two-week randomised trial in 32 adults: 600 mg of DHA a day, provided by an algal oil or by cooked salmon, produced an equivalent rise, about +80% in plasma and +25% in red blood cells. The study measured no clinical effect.
Which omega 3-rich foods for breakfast?
Flaxseeds ground at the last moment, a handful of walnuts or a drizzle of raw flaxseed oil on fruit or toast: these habits provide ALA from the morning. Keep the oil cool and grind the seeds as you go, because these fragile fats don't cope well with air and light.
Which plant omega 3 source should you choose?
The right choice depends on the omega 3 you are looking for. For ALA, the seeds and oils of flax, camelina and hemp, or walnuts, will do. For EPA and DHA, the long-chain ones, the direct source remains microalgae, notably as microalgae oil; dulse provides only a little EPA.
Do you need to consume omega 3 every day?
Yes in the sense of the official reference values, which are expressed per day: for adults, ANSES sets ALA at 1% of energy intake, or about 2.2 g for 2,000 kcal, 250 mg of DHA and 250 mg of EPA. These values are meant to be considered across all your meals, as part of a varied and balanced diet and a healthy lifestyle.
References
- FAO, 2026. The State of World Fisheries and Aquaculture 2026. Blue Transformation: turning vision into impact. FAO, Rome.
- Gladyshev MI, Sushchik NN, Makhutova ON, 2013. Production of EPA and DHA in aquatic ecosystems and their transfer to the land. Prostaglandins & Other Lipid Mediators, 107:117-126.
- Williams CM, Burdge G, 2006. Long-chain n-3 PUFA: plant v. marine sources. Proceedings of the Nutrition Society, 65(1):42-50.
- Burdge GC, Wootton SA, 2002. Conversion of alpha-linolenic acid to eicosapentaenoic, docosapentaenoic and docosahexaenoic acids in young women. British Journal of Nutrition, 88(4):411-420.
- Burdge GC, Calder PC, 2005. Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults. Reproduction Nutrition Development, 45(5):581-597.
- Arterburn LM, Oken HA, Bailey Hall E, Hamersley J, Kuratko CN, Hoffman JP, 2008. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid. Journal of the American Dietetic Association, 108(7):1204-1209.
- ANSES, 2010. Les lipides ; avis relatif à l'actualisation des apports nutritionnels conseillés pour les acides gras (saisine 2006-SA-0359). ANSES.
- EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA), 2010. Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal, 8(3):1461.
- Lopes D, Melo T, Meneses J, Abreu MH, Pereira R, Domingues P, Lillebø AI, Calado R, Domingues MR, 2019. A New Look for the Red Macroalga Palmaria palmata: A Seafood with Polar Lipids Rich in EPA and with Antioxidant Properties. Marine Drugs, 17(9):533.
- Commission européenne, 2012. Règlement (UE) n° 432/2012 de la Commission du 16 mai 2012 établissant une liste des allégations de santé autorisées portant sur les denrées alimentaires. Journal officiel de l'Union européenne.
Last updated: November 2026. Article written and validated by Éric Viard, founder of Biovie since 2007 and ISTOM engineer, co-author of « Algues au quotidien » (Gallimard, 2024), Best Cookbook in the World, Gourmand Cookbook Awards 2025, and Best Cookbook in France, Académie Nationale de Cuisine 2025.
The information presented in this article is provided for information purposes only and does not constitute medical advice. Consult a healthcare professional before making any change to your diet or supplementation.