Essential Fatty Acids: What They Are, Why They Matter, and How to Get Enough

Essential fatty acids (EFAs) are types of fats that our bodies can’t make on their own, meaning we must get them from food or supplements. They play crucial roles in brain health, heart health, inflammation control, and cell function — making them just as vital as vitamins and minerals.

In this article, I’ll cover:

• What essential fatty acids are

• The main types and their food sources

• Why the omega-3 to omega-6 balance matters

• How much fatty fish you need for optimal omega-3 intake

• When and how to supplement — whether you’re an omnivore, vegetarian, or vegan

• Why you might also want to know about omega-7

If you want to learn more about healthy fats in general, check out my guide to the best healthy fats for your body.

What Are Essential Fatty Acids?

The two main essential fatty acids are:

• Omega-3 fatty acids – including ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid)

• Omega-6 fatty acids – primarily linoleic acid

While both are necessary, modern diets often provide too much omega-6 and too little omega-3, which can tilt the body toward a pro-inflammatory state.

Food Sources of Essential Fatty Acids

Omega-3 sources:

• ALA (plant-based): flaxseeds, chia seeds, walnuts, hemp seeds

• EPA and DHA (marine-based): fatty fish like salmon, mackerel, sardines, herring, anchovies, trout and seafood like oysters, mussels

• Algal oil: a vegan source of EPA and DHA

Omega-6 sources:

• Vegetable oils (sunflower, corn, soybean, safflower)

• Nuts and seeds

What about Omega-3 to Omega-6 Ratio?

Historically, humans consumed omega-6 and omega-3 in roughly equal amounts. Today, the typical Western diet can have a ratio as high as 15:1 — heavily skewed toward omega-6.

While omega-6 fats are not “bad,” excessive amounts can compete with omega-3s for the same enzymes in the body, making it harder to produce anti-inflammatory compounds from EPA and DHA.

Balancing your intake doesn’t mean cutting out omega-6 foods— it means increasing omega-3 intake from marine and algal sources.

Why EPA and DHA Are Key?

ALA from plants is valuable, but the body converts it into EPA and DHA inefficiently (often less than 5–10%). That’s why direct sources of EPA and DHA from fatty fish or algae are the most effective way to raise your omega-3 levels.

These long-chain omega-3s are linked to:

• Reduced risk of heart disease

• Improved brain health and mood

• Healthy pregnancy outcomes

• Reduced inflammation

How Much Fatty Fish Should You Eat?

Most experts as well as dietary guidelines (like Estonia's dietary guidelines) recommend:

• 2–3 servings of fatty fish per week (about 150g per serving, depending on the fat content of the fish)

• This provides roughly 250–500 mg of combined EPA and DHA daily — the amount associated with general health benefits

If you don’t eat fish this often, supplementation of Omega-3 (with DHA and EPA) is worth considering.

Supplementing with Essential Fatty Acids

While the best way to get omega-3 fatty acids is from food, supplements can help bridge the gap if your fatty fish intake is low.

For Omnivores

If you eat fish but not regularly, a high-quality fish oil supplement can help you meet your needs. Look for:

• EPA + DHA content clearly listed on the supplement label (not just “total omega-3s”)

• At least 840–1,000 mg of combined EPA and DHA per day for general heart and brain support. Dr. William Harris (a leading researcher in the omega-3 fatty acid field for over 40 years) has an Omega-3 Index calculator, which allows you to put in your current Omega-3 index to determine how much you should supplement to reach the desired level in your blood. In Estonia you can test your Omega-3 index at Synlab. Nutrition scientist Simon Hill recommends 1.5-2 grams of DHA/EPA per day for optimal Omega-3 levels.

• Third-party testing for purity and absence of heavy metals

For Vegans & Vegetarians

Since fish is off the menu, algal oil is your best source of EPA and DHA. When choosing an algal oil supplement:

• Ensure it is 100% algae-sourced (not blended with other oils)

• Check that the DHA and EPA amounts are specified, ideally in the range of 840–1,500 mg per day if you don’t consume any fatty fish

• Avoid products that inflate their omega-3 numbers with ALA-rich oils like flaxseed — these are not as efficiently converted into EPA and DHA

Label-Reading Tips for supplements from Simon Hill

• Always check the active forms (EPA, DHA, and sometimes DPA) — not just the total omega-3 figure

• Many brands list small doses (200–300 mg), which can prevent deficiency but may not deliver the full cardiovascular or cognitive benefits shown in research

• If you have a specific condition (e.g., cardiovascular disease, high triglycerides, type 2 diabetes) and are taking statins, your doctor might recommend a prescription form of EPA (like icosapent ethyl) based on clinical evidence from trials like REDUCE-IT

Who Could Benefit from Omega-3 Supplementation?

Some groups may find it especially beneficial to take omega-3 supplements:

• Pregnant and breastfeeding women– DHA and EPA are vital for healthy growth and brain development in babies. If you’re avoiding fish during pregnancy, your healthcare provider may suggest a supplement.

• Older adults – Regular omega-3 intake later in life may help protect cognitive function and lower the risk of dementia.

• People who don’t eat seafood – Without fish in your diet, it’s hard to get adequate DHA and EPA. While a healthy plant-based diet already supports heart health, supplementation ensures you cover any gaps in omega-3 intake.

A Quick Note on Omega-7

While not “essential” in the dietary sense, omega-7 fatty acids (like palmitoleic acid) are found in macadamia nuts and sea buckthorn oil. Early research suggests they may:

• Support healthy cholesterol levels

• Improve insulin sensitivity

• Reduce inflammation

They’re not a replacement for omega-3s, but they can be a valuable addition to an overall healthy fat intake.

Key Takeaways

• Essential fatty acids — especially omega-3s — are critical for heart, brain, and overall health.

• Prioritise direct sources of EPA and DHA from fatty fish or algal oil.

• Aim for 2–3 servings of fatty fish per week, or supplement if you fall short.

• Check supplement labels for EPA + DHA content and choose based on your dietary preferences.

• Certain groups — including pregnant people, older adults, and those who avoid seafood — may benefit most from supplementation.

If you want to receive professional guidance on how to make healthier dietary choices, don't hesitate to reach out to me for nutrition counselling at info@katrinpeo.com.