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Essential fatty acid

Omega-3s, the membrane fats

Omega-3s are polyunsaturated fats: ALA must come from food, and EPA and DHA help build the membranes around every cell, especially in the eyes and brain2.

FatsTracked in gDaily target4 sources · checked 2026-09-27

How much you need

A raw salmon fillet with lemon wedges on a white plate, surrounded by garlic, spring onions and spices on a wooden table
Photo: David B Townsend on Unsplash (Unsplash License)
01 What it does

What omega-3 does for you.

Cell membranes

Omega-3s are part of the membranes that surround each cell in your body2.

Eyes

DHA levels are especially high in the retina2.

Brain

DHA is also concentrated in brain cells2.

Heart & triglycerides

Fatty fish is linked with heart health, and more EPA and DHA lowers triglyceride levels2.

Body signals

Used to make eicosanoids, signals for the heart, lungs, immune and hormone systems1.

02 How your body uses it

How your body uses omega-3s.

How your body uses omega-3s: Food → Small intestine → Lymph & blood → Liver → Cell membranes → Eicosanoids. Omega-6 fats compete with ALA Liver.01FoodFish, seeds, nuts, oils02Small intestineAbout 95% absorbed03Lymph & bloodCarried in chylomicrons04LiverALA → EPA → DHA (a little)05Cell membranesEyes, brain, sperm06EicosanoidsSignalling moleculesOmega-6 fatsShare the same enzymescompete with ALAHow your body uses omega-3s: Food → Small intestine → Lymph & blood → Liver → Cell membranes → Eicosanoids. Omega-6 fats compete with ALA Liver.01FoodFish, seeds, nuts, oils02Small intestineAbout 95% absorbed03Lymph & bloodCarried in chylomicrons04LiverALA → EPA → DHA (a little)Omega-6 fatsShare the sameenzymes05Cell membranesEyes, brain, sperm06EicosanoidsSignalling molecules

Omega-3 fats are absorbed about as well as other fats and travel in chylomicrons through the lymph into the blood1. The liver converts only a small share of ALA into EPA and DHA, so getting them directly from food or supplements is the practical way to raise them1.

03 Where to get it

Foods and other sources.

FlaxseedChia seedsWalnutsCanola oilEdamameSalmonSardinesMackerelHerring

Vegetarian

Food and servingAmount
Flaxseed oil, 1 tbsp7.26 g ALA
Chia seeds, 1 oz5.06 g ALA
Walnuts, English, 1 oz2.57 g ALA
Flaxseed, whole, 1 tbsp2.35 g ALA
Canola oil, 1 tbsp1.28 g ALA
Edamame, frozen, prepared, ½ cup0.28 g ALA

Non-vegetarian

Food and servingAmount
Salmon, Atlantic, farmed, cooked, 3 oz1.24 g DHA + 0.59 g EPA
Herring, Atlantic, cooked, 3 oz0.94 g DHA + 0.77 g EPA
Sardines, canned in tomato sauce, 3 oz0.74 g DHA + 0.45 g EPA
Mackerel, Atlantic, cooked, 3 oz0.59 g DHA + 0.43 g EPA

Plant foods provide ALA, while fish and seafood provide EPA and DHA, which fish get from microalgae in the food chain1. Amounts per serving from1.

Fortified foods

Some brands of eggs, yogurt, juices, milk, soy drinks and infant formulas have added omega-3s2.

04 How much you need

Your daily reference amounts.

The same reference table draws the reference lines on your charts in Ayuvo. Needs differ in pregnancy and breastfeeding, which are not covered here.

Omega-3: daily AI by age and sex
AgeWomenMen
19–301.1 g1.6 g
31–501.1 g1.6 g
51–701.1 g1.6 g
71+1.1 g1.6 g

AI (Adequate Intake) is used when there is not enough evidence for an RDA: an amount assumed to be enough. Per day, for adults14.

  • The AI applies to alpha-linolenic acid (ALA) only; EPA and DHA have no separate recommended amount.
Omega-3 reference amounts for adults aged 31–50: Women 1.1 · Men 1.6 gWomen 1.1 · Men 1.6 g0Adults 31–50, per day
Below the recommended amountMeets the reference
05 Balance

Too little, too much.

Signs like these have many possible causes. They are a reason to talk to a clinician, not to self-treat.

Too little

Omega-3 deficiency is very rare in the United States, but a lack of essential fatty acids can affect the skin2.

  • Rough, scaly skin
  • Red, swollen, itchy rash
  • Dermatitis

Too much

Side effects of omega-3 supplements are usually mild, though very high doses may lengthen bleeding time1.

  • Unpleasant taste or bad breath
  • Heartburn or nausea
  • Diarrhea
  • Headache
  • Smelly sweat
  • Possible interaction with warfarin
06 Supplements

Supplement forms.

Omega-3 supplements come in several forms with widely varying doses, so check the label for the type and amount of EPA and DHA1.

Fish oil

Provides EPA and DHA; methyl mercury is removed during processing and has not been found in supplements1.

Krill oil

Provides omega-3s mainly as phospholipids; studies differ on whether they are absorbed better1.

Cod liver oil

Provides EPA and DHA plus vitamins A and D, in amounts that vary by product3.

Algal oil

A vegetarian source that usually provides DHA, and sometimes EPA1.

Flaxseed oil

Provides ALA rather than EPA or DHA3.

Supplements can interact with medicines. Talk to a clinician or pharmacist before you start one, especially at high doses.

07 Key points

Remember these five.

  1. ALA comes from plant foods; EPA and DHA come mainly from fish and seafood.
  2. Your body turns only a small amount of ALA into EPA and DHA.
  3. Flaxseed, chia seeds and walnuts are rich vegetarian sources of ALA.
  4. Algal oil is a vegetarian source of DHA.
  5. Omega-3 supplement side effects are usually mild, such as bad breath or heartburn.
FAQ

Questions about omega-3.

Can vegetarians get enough omega-3?

Most people get enough ALA from foods like flaxseed, chia seeds, walnuts and canola oil. The body converts only a little ALA into EPA and DHA, so algal oil is a vegetarian option for DHA.

Is there a blood test for omega-3?

Most clinicians do not check omega-3 status, and experts have not set normal ranges. Researchers sometimes measure EPA and DHA in red blood cells, called the omega-3 index, which reflects roughly the past four months.

Is fish oil the same as omega-3?

Fish oil is one source of the omega-3s EPA and DHA. Other supplements include krill oil, cod liver oil, algal oil and flaxseed oil, which provides ALA instead.

Get started

Track omega-3 in Ayuvo.

Ayuvo charts omega-3 by day, week, month and year, with the reference lines from this page, personalised by age and sex where they differ. Supplements you log in Medications count too. Free, with no account.

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Sources

Facts on this page come from these sources, checked on the dates shown. Intake numbers come from Ayuvo's shared reference table, which cites the sources marked for them.

  1. Omega-3 Fatty Acids: Fact Sheet for Health Professionals · NIH Office of Dietary Supplements checked 2026-09-27
  2. Omega-3 Fatty Acids: Fact Sheet for Consumers · NIH Office of Dietary Supplements checked 2026-09-27
  3. Omega-3 Supplements: What You Need To Know · National Center for Complementary and Integrative Health checked 2026-09-27
  4. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) · National Academies of Sciences, Engineering, and Medicine checked 2026-09-27

General information, not medical advice. This guide is for healthy adults and does not cover pregnancy, breastfeeding, children or medical conditions. It cannot diagnose or treat anything. Talk to a clinician before starting high-dose supplements, or if you think you may have too little or too much of a nutrient. Spotted an error? Email us.

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