No. Chia and flax are loaded with omega-3, but it’s a different omega-3 than the one in fish — the plant form (ALA), not the EPA and DHA your heart and brain actually run on. Your body has to convert ALA into EPA and DHA before it can use it that way, and it does that job badly: single-digit percentages, and almost none of it reaches DHA. So a tablespoon of chia is real food with real omega-3 on the label, but most of that number never becomes the omega-3 the research is talking about.
That’s the whole answer. The rest is the honest detail — including the part where, for a lot of people, you don’t need a seed or a supplement.
Two different molecules wearing the same name
“Omega-3” isn’t one thing. It’s a family. The one in seeds is alpha-linolenic acid (ALA) — a short-chain, 18-carbon fat. The ones in oily fish are EPA and DHA — longer chains (20 and 22 carbons) that your cell membranes, your triglycerides, and your brain are built to use directly.
Chia and flax carry a lot of ALA. Fish carries preformed EPA and DHA. When a chia label brags “more omega-3 than salmon,” it’s counting ALA grams and quietly hoping you won’t ask whether your body can turn them into the fish kind. Mostly, it can’t.
The conversion tax nobody prints on the bag
Here’s the number that decides the whole question. According to the U.S. National Institutes of Health Office of Dietary Supplements, adults convert only about 5 to 8% of ALA into EPA, and less than 4% into DHA — often far less, closer to a fraction of a percent for DHA (NIH ODS Omega-3 Fact Sheet). Women of reproductive age convert at the higher end — up to roughly 21% to EPA — likely an estrogen effect. For most everyone else, the tax is brutal.
Put it in food terms. A tablespoon of chia or ground flax can hold around 2.4 grams of ALA. Run that through the conversion rates above and you’re left with maybe 0.05 to 0.24 grams of usable EPA and DHA — the range depends on who you are and what else you eat. A three-ounce piece of salmon delivers close to a full gram of EPA and DHA already assembled, no conversion tax owed. That’s why the two “omega-3” numbers aren’t comparable, even when the seed’s number looks bigger on paper.
It gets worse if your diet is high in omega-6 — the linoleic acid in most vegetable and seed oils. Omega-6 and ALA compete for the same enzymes, so a typical Western plate quietly throttles the conversion even further.
What happens when you test it in people
This isn’t just biochemistry on a whiteboard. In a randomized, double-blind, placebo-controlled trial in adults with high cholesterol, EPA and DHA improved blood lipids and inflammation markers — and ALA did not (Zhou et al., 2019, Molecular Nutrition & Food Research). More broadly, researchers now accept that in people eating an ordinary Western diet, you generally cannot raise your blood DHA by taking ALA. The conversion is simply too weak to move the number that matters.
To be fair — and we’d rather be fair than sell you something — it’s not zero. A carefully controlled year-long feeding study in 2025 found that flaxseed-oil ALA can nudge long-chain omega-3 levels up more than expected when the whole diet is managed for it (News-Medical, Dec 2025). So the door isn’t nailed shut. It’s just that “eat a tablespoon of chia and skip the fish” is not how you walk through it.
You might not need any of this — seeds or us
Here’s the part a supplement seller isn’t supposed to say. If you eat oily fish — salmon, sardines, mackerel, herring — twice a week, you’re already getting preformed EPA and DHA and there’s very little gap to fill. Not with chia. Not with flax. Not with a capsule, ours included. Keep eating the fish and you can stop reading here.
And if you’re vegan or vegetarian and you genuinely want EPA and DHA, the honest answer still isn’t seeds — it’s algae oil, which is where the fish get their omega-3 in the first place. That’s the plant-based source that actually delivers the long-chain fats without the conversion tax. It isn’t us, and we’ll say so.
None of that makes chia or flax bad. They’re excellent food — fiber, protein, minerals, and yes, some omega-3. Eat them for what they are. Just don’t ask a tablespoon of seeds to do a salmon’s job. (For the food-first version of this answer, see our short note on dietary sources of omega-3.)
Where Captains fits — and where it doesn’t
Captains Krill Oil™ is the fish-type omega-3: preformed EPA and DHA, carried in the phospholipid form that krill store it in. It’s a raw natural catch, extracted mechanically on the boat rather than pulled out with chemical solvents in a factory — which also means the oil is a real animal product that varies a little lot to lot, the way real food does. We test lots at random and they come back strong. Twenty years of doing it the same way.
But Captains only earns its place if you actually have a gap — you don’t eat the fish, and you want the EPA and DHA without the seed-conversion lottery. If you already eat oily fish twice a week, you don’t need us. That’s not modesty; it’s just the truth about where this particular oil helps and where it doesn’t.
Honest answer, not a pitch. — captainskrilloil.com
Frequently asked questions
Is chia or flax better than fish oil for omega-3?
For the plant form (ALA), seeds are excellent. For the EPA and DHA your heart and brain use directly, fish (or fish/krill oil) wins clearly, because your body converts only a small fraction of ALA into those long-chain fats. Different job, different molecule.
How much ALA do I need to equal the EPA and DHA in fish?
There’s no clean ratio, because conversion varies by person, sex, and diet. As a rough sense of scale: a tablespoon of chia (~2.4 g ALA) might yield only 0.05–0.24 g of usable EPA and DHA, while a 3-ounce serving of salmon delivers close to a full gram already formed. That’s why “gram for gram” comparisons on seed labels are misleading.
Can vegans get enough EPA and DHA from seeds?
Not reliably. In people on typical diets, ALA supplementation doesn’t dependably raise blood DHA. Vegans and vegetarians who want EPA and DHA are usually better served by an algae-based oil, which supplies the long-chain fats directly without needing conversion.
Do women convert ALA better than men?
Somewhat. Women of reproductive age can convert up to roughly 21% of ALA to EPA — likely an estrogen effect — versus single digits for most adults. Even at the high end, conversion to DHA s