Home » Health and Nutrition » Vegetarian Nutrients of Concern #6: Fish Oil

Vegetarian Nutrients of Concern #6: Fish Oil

As we continue on with our discussion on nutrients that vegetarians should pay attention to, we finish with Omega 3 fatty acids, often referred to as fish oils.  There’s a lot of conversation around fish oil and it’s health benefits, and it’s obviously not a nutrient vegetarians come by easily.

Basically, when we talk about fish oil, we are really talking about 2 different fatty acids, DHA and EPA. These fats are considered non-essential because technically, our bodies can make both of them from another fat, known as ALA.  

ALA is an essential nutrient, which simply means that we have to get it from our diet. It is found in many foods. Our biggest source is cooking oil, particularly canola and soybean oil. It is also found in flax seeds, pumpkin seeds, walnuts, and tofu.

ALA is considered to be heart-healthy and anti-inflammatory. However, additional benefits come from EPA and DHA.  Some research suggests that our body only converts ~1% of the ALA we eat into EPA/DHA.

For much of our discussion, we will be concerned with EPA/DHA.

bunch of walnuts, shelled
Photo by Tom Hermans on Unsplash


Omega-3’s (including ALA) are a part of all of your cell membranes. DHA is particularly prevalent in the cells of the eyes, the brain, as well as sperm cells. 

All fats provide the body with energy, storage, and are the foundations for some hormones as well as chemicals known as eicosanoids that are involved in cell signaling. Because of this, fats play a role in our cardiovascular, pulmonary, immune, and endocrine systems.

Eicosanoids that are made from omega-6 fats tend to be inflammatory and lead to clot formation at much higher rates than those that are made from omega-3 fats. In fact, omega-3 fats are largely considered to be anti-inflammatory.

The types of fats we eat “compete” for the same enzymes. So even though we need both omega 3’s and omega 6’s we want the omega 3’s to “win.”

In general, DHA is beneficial to the brain and the eyes, whereas EPA is beneficial for the heart. Recent studies, however, seem to indicate that prescription doses of purified EPA is necessary for real improvement in your cardiac risk factors.

Intake of EPA and DHA are linked to:

Improved symptoms of depression and anxiety

Better management and outcomes in bipolar disorder and schizophrenia

Greater brain development in utero and early life

Reduced risk of Alzheimer’s disease and other causes of dementia

Improved risk factors for heart disease (lower “bad” cholesterol and triglycerides, higher “good” cholesterol.

Lower rates of chronic inflammation

Reduced risk of auto-immune diseases

Prevention of some cancers

Flax seeds on wooden spoon on white background

Recommended Intake

There is no set standard for intake for DHA and EPA, the “fish” oils, mostly because they are considered non-essential nutrients.  For those that choose to eat fish, 2 servings of fatty fish per week are considered adequate intake of fish oil.  

Some improved health outcomes are seen when supplements are taken at a combined 300 mg per day.


Fish is the main source of dietary EPA and DHA.  The amount of fish oil in the fish depends on a range of factors including, but not limited to their diet, water temperature, and farmed vs wild-caught.

Your omnivorous friends and family should look for cold-water fish such as tuna, salmon, mackerel, and sardines. Bass, tilapia, and cod have less, and shellfish have even less.

For us vegetarians, certain egg and dairy products are now fortified with DHA.

Despite being colloquially known as fish oil, fish don’t actually make DHA and EPA. Instead, they get it from their food: microalgae and phytoplankton.

Nowadays, we have algal-based supplements for “fish” oil.  I often recommend these products for vegetarians and vegans alike. Just make sure they contain both EPA and DHA.

multi colored eggs in a carton
Some eggs and dairy products are fortified with DHA/EPA

Symptoms of Deficiency

Symptoms of fat (any fat) deficiency include rough, scaly skin and dermatitis. Unfortunately at this time, we do not have a set laboratory value in which low levels of EPA and DHA begin to result in poor visual, neural, or immune system function.

All that being said, a true fat deficiency is almost non-existent in the United States. Furthermore, inadequate intake of DHA and EPA are not going to cause any overt symptoms or be caught on routine blood work.

Although high intakes of fish oil are linked to better health outcomes repeatedly in studies, low intake does not appear to have a direct correlation to poor health!

Squirrel eating a walnut
Photo by Caleb Martin on Unsplash

Symptoms of Toxicity

There is no known toxicity of EPA and DHA.  Very high-fat diets have been known to cause NAFLD; fatty liver that can lead to cirrhosis/liver failure if untreated.

Very high doses of fish oil supplementation (>2 grams per day) can lead to stomach upset and headache, which resolves when you stop taking the supplement.

algae covered rocks on a beach
Photo by Younmyoung Cho on Unsplash
Vegetarian DHA/EPA supplements are made from algae

Should I take a supplement?

It really depends on you and your individual risk factors.

Despite EPA’s ability to improve your cholesterol, high doses of DHA have been shown to do the opposite and actually raise your LDL “bad cholesterol.”

ALA, the precursor to DHA and EPA, has its own set of health benefits, beyond just its ability to inefficiently convert to the “fish oils,” EPA and DHA.  This is a fat that is readily available in our food supply.

In general, vegetarians show much lower levels of EPA and DHA than meat-eaters, but this has not shown in clinical impact on health outcomes. In fact, vegetarians tend to have lower rates of chronic conditions such as heart disease and diabetes.

If you have high cholesterol that won’t budge, medication-resistant mental health disorders, or a strong family history of auto-immune disorders, it may be worth it to you to try. And studies show that algal-based supplements are as effective as fish oil-based supplements.

Consider 300 mg of combined DHA and EPA 3-4 times per week.

Those that take Coumadin or other anticoagulant medications should not take fish oil supplements without informing their doctor.

What supplementation won’t do

As always, supplementation won’t overcome a poor diet. It is always better to get our nutrition from food.  Eating a veggie burger and fries, vegetarian fast food, and a lot of sugar can’t be corrected with a pill. 

Any concern for omnivores?

It’s easier for them, but if they don’t like fish or only eat it fried, they may not be getting enough either.


National Institutes of Health

Penn State

Health Line

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Are You an Unhealthy Vegetarian?






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