The Vegan Omega-3 Showdown: Flax vs. Chia vs. Algae

Omega-3 fatty acids have been widely studied for the many roles they play in supporting overall human health. These essential fats are part of every cell membrane in the body, helping to maintain their structure and fluidity while supporting normal heart, brain, and eye function.* 

But unlike many nutrients, the body cannot produce omega-3s in meaningful amounts on its own. That’s why they’re considered “essential” fats that must come from our diet. 

For most people, that means seafood — fish, like salmon, tuna, sardines, mackerel, and anchovies. 

But what about people who avoid fish? Where can vegans and vegetarians find a reliable dietary source of omega-3s? Or even people who are concerned about overfishing? 

The spotlight for them falls on a small cast of plant-based food, such as walnuts, leafy greens, edamame, winter squash, brassica vegetables, and berries. But the three that appear most often on health blogs, product labels, and grocery shelves are flaxseed, chia seed, and algae. 

Do they all deliver the same benefits? Or are some better for everyday nutrition, supplying the forms of omega-3 the body can directly use? 

That’s what we’re here to unpack. 

But before we begin, here’s the shorthand you’ll see throughout this showdown. 
 
Omega-3s occur in three main forms: 

• ALA (alpha-linolenic acid): Naturally present in plant food, such as flax, chia, walnuts, and leafy greens. 
 
• EPA (eicosapentaenoic acid): Found in marine sources such as fish and algae. 
 
• DHA (docosahexaenoic acid): Also present in marine sources such as fish and algae. 
 

Meet the contenders 

Flaxseed (Linum usitatissimum) 

Flax has earned its reputation as a nutrient-rich superfood for good reason. These tiny golden or brown seeds are among the richest plant sources of ALA, a short-chain omega-3 fatty acid (explained later on). 

Ground flaxseed or flaxseed oil often shows up in recipes for smoothies, baked goods, and breakfast bowls. Pro tip: whole flax seeds mostly just pass through us, so a few of those decorating the top of your whole grain bread mostly look pretty without bringing big benefits. 

Chia seed (Salvia hispanica) 

Chia seeds, also rich in ALA, deliver a comparable omega-3 punch. They swell into a gel form when soaked and are commonly used to make puddings, overnight oats, and salads. 

Algae (Schizochytrium spp.) 

Long before fish became a common source of omega-3s, microalgae were already producing them in the ocean. In fact, fish contain EPA and DHA because they consume algae directly or eat smaller organisms that feed on algae. 

Together, these foods highlight the two very different paths omega-3s can take in the body — bringing us to the heart of the matter. 

The essential divide 

Flax and chia supply omega-3s in the form of short-chain ALA, while algae provides the long-chain forms, EPA and DHA. 

Now here’s the challenge with ALA: the body cannot use it directly. It must first be converted into EPA and DHA — the long-chain omega-3s the body uses in many essential functions. 

This is the key difference — and it raises the central question: how efficiently can the body carry out that conversion, and is ALA alone enough for vegetarians and vegans? 

The conversion catch 

The body can convert ALA into EPA and DHA — but the process is strikingly inefficient. 

• On average, it is estimated that only about  5–10% of ALA is converted into EPA. 

• Conversion into DHA is estimated to be even lower, typically below 1%. 

• These numbers can vary depending on age, gender, genetics, and overall diet. For example, women of childbearing age tend to convert ALA more efficiently than men, likely due to hormonal influences, but even then, the rates remain low. 

So, what does this mean in everyday life?  

Eating flax or chia may add plenty of ALA to your diet, but only a small fraction becomes the long-chain omega-3s — EPA and DHA — that the body can use directly. That’s why flax and chia shine as nutrient-rich foods, but not as dependable sources of EPA and DHA. Their contribution is limited by the body’s biology. 

Label math 

Now here’s where labels can get confusing. 

Flax and chia products note their omega-3 content in terms of “ALA milligrams per serving” on the Supplement Facts label. 

For example, a tablespoon of flaxseed oil may contain over 7,000 mg of omega-3s — but it’s important to remember that this is all in ALA form. And because the body converts only a small fraction of ALA, the usable amount of EPA and DHA is much lower than the impression one may get from reading the label. 

By contrast, algae oil supplements list the specific quantities of EPA and DHA they deliver. 

A serving might say “400 mg DHA + 200 mg EPA”, which reflects the actual long-chain omega-3s your body can put to work immediately without requiring extra conversion steps. 

This is why comparing flax or chia oil to algae oil isn’t a simple one-to-one comparison. 

The “total omega-3” number on a plant oil label may look impressive, but without specifying EPA and DHA, it doesn’t give the complete picture. 

The knockout advantage: why algae wins 

By this point, the showdown makes one thing clear: flax and chia are excellent whole foods, but their ALA content makes them also-rans in the vegan Omega-3 race.  

Omega-3 derived from algae wins because: 

• It has ready-made EPA + DHA: Algae supplies long-chain omega-3s in the forms the body can use directly, eliminating the need for conversion. 

• It is sustainable by design: Growing algae doesn’t strain marine ecosystems, making it a renewable source of omega-3s. 

• It is vegan/vegetarian-friendly: Unlike fish oil, algae oil aligns with plant-based diets while providing EPA and DHA. 

This combination — direct, sustainable, and vegan — makes algae the most reliable plant-based source of omega-3s today, and a simple way to help close the omega-3 gap without fish.   

From showdown to solution 

Now that algae has emerged as the clear winner in the vegan omega-3 stakes, the next question is: what’s a reliable way to get it? 

That’s where Natural Factors RxOmega-3 Algae comes in. Each serving of 2 softgels per day features: 

• Direct EPA + DHA: 400 mg DHA and 200 mg EPA in forms the body can use directly. (Also includes 170 mg of other omega-3 fatty acids.) 

• Indoor-grown quality: Cultivated in carefully controlled indoor environments, away from pollutants, heavy metals, and microplastics sometimes present in open water. 

• Allergen-friendly and clean: Free from dairy, gluten, soy, shellfish, tree nuts, GMOs, and artificial additives — and third-party tested by ISURA® for over 800 potential contaminants.  

Core benefits of RxOmega-3 Algae* 

• Brain health: DHA is a major structural component of brain tissue, making up more than 40% of the brain’s polyunsaturated fatty acids. Adequate intake of DHA, along with EPA, helps support normal cognitive and neurological function.* 
 
• Cardiovascular health: Helps maintain healthy lipid levels already within the normal range while also supporting normal circulation and healthy blood vessel function.* 

• Immune health: Helps support normal immune function as part of overall wellness.* 

• Cell membrane function: Essential components of cell membranes, helping support the transport of nutrients into cells and the removal of byproducts, for overall cell health.* 
 
• Eye health: DHA is highly concentrated in the retina, where it helps support healthy vision and normal eye function throughout life.* 
 

Closing the omega-3 gap 

Research suggests that  9 in 10 Americans don’t get enough omega-3s from their diet. They don’t eat sufficient direct sources of EPA and DHA, and many rely heavily on a western diet that emphasizes meat protein over fish. 
 
That’s why choosing a direct, reliable source of EPA and DHA is especially important for people who don’t consume fish. With RxOmega-3 Algae, you’re not relying on conversion, estimates, or label math. You’re getting a clean, consistent source of the omega-3s that matter most, in a form your body can use right away. 

In other words, algae makes the choice simple — a once-a-day option for turning good intentions into consistent omega-3 intake. 

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.