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VITAMINS & SUPPLEMENTS · GUIDE

Omega Fatty Acids Explained: Omega-3, Omega-6 and Omega-9

A plain-language overview of omega-3, omega-6 and omega-9 fats: which ones are essential, where they come from in food, what research does and does not show, and where to read more.

Content last updated . This page has not been medically reviewed.

Back to Omega Fatty Acids
Quick answer
"Omega" is a family name for groups of fats. The NHS (UK) says there are two main types of polyunsaturated fat, omega-3 and omega-6, and that some types of each cannot be made by the body, so small amounts must come from food. [1] Omega-9 is a monounsaturated fat group, usually meaning oleic acid, and the sources we read do not list it as essential (see below). This page is the map of the Omega Fatty Acids library. It gives information, not personal advice.

The three families at a glance

FamilyMain membersEssential?Typical foodsSource
Omega-3ALA (plant); EPA and DHA (seafood, algae)ALA is described as nutritionally essential; EPA and DHA can be made from ALA only in small amountsOily fish, flaxseed, walnuts, chia, rapeseed oil[2][3][1][4]
Omega-6Linoleic acid (LA), arachidonic acid (ARA)Strictly speaking, only LA is essentialVegetable oils such as rapeseed, corn and sunflower; nuts such as walnuts, almonds and cashews[2][1]
Omega-9Oleic acidNot described as essential in the sources we readOlive oil, rapeseed oil, avocados, some nuts[1][2]

How this library labels evidence

We use plain labels: established nutritional role (the body needs it), evidence in adequately nourished people, promising but limited, mixed, insufficient evidence and marketing claim. Where we searched and found nothing usable, we write "Proper evidence not found" and say what we searched. Mechanism (what a fat does in a cell) is kept separate from outcome (whether a person gets healthier).

Essential means "must come from food"

MedlinePlus (US National Library of Medicine) says omega-3 and omega-6 fats are essential fatty acids that the body needs for brain function and cell growth, and that the body does not make essential fatty acids, so they must come from food. [5] The European Food Safety Authority (EFSA) wrote in 2009 that ALA is considered nutritionally essential because it is the starting point for EPA and DHA. [2] For details, see What are fatty acids?.

What the main agencies say about amounts

Body and yearStatementWho it covers
NHS (UK), page updated 2025At least 2 portions of fish a week, one of them oily; most people get enough omega-6 [1][6]UK adults
EFSA (EU), 2012 news story250 mg a day of EPA plus DHA is an adequate intake for general cardiovascular health [7]Healthy adults and children, EU
EFSA (EU), 2009 opinionProposed label reference values: ALA 2 g, LA 10 g and EPA plus DHA 250 mg a day. These are for food labels, not personal targets. [2]Adults, EU labelling
US National Institutes of Health fact sheetsThe pages returned an access error when we tried to read them, so we could not verify US Adequate Intake figures and do not quote any.Not verified

These are different kinds of numbers from different countries. They are not one universal target. See RDA, AI, DV and UL for how the terms differ.

What research shows, in brief

  • Seafood versus supplements. NCCIH (US National Center for Complementary and Integrative Health) says the evidence for benefits from seafood is stronger than for omega-3 supplements. [8]
  • Omega-3 supplement trials and heart outcomes. A 2018 Cochrane review of randomized trials lasting at least 12 months found little or no effect of increasing long-chain omega-3 on all-cause mortality, and that it probably makes little or no difference to coronary heart disease events. [9] This does not transfer to every product or person; the Evidence pages cover each question separately.
  • Omega-6. Large cohort analyses link higher linoleic acid levels with lower cardiovascular risk, while a Cochrane review of trials found low-quality evidence of little or no difference. [10][11] See omega-6 fatty acids.
  • Omega-9. Proper evidence not found for omega-9 on its own: a PubMed search for human trials of oleic acid supplementation returned nothing, and the "omega-3-6-9" trials we found are small and mix several fats (see the FAQ). See omega-9 and monounsaturated fats.

Eating patterns

In the sources we read, the practical eating advice is food-based: fish a week, plant sources of omega-3, and swapping saturated fat for unsaturated fat. [1][5] Plant options include flaxseed, rapeseed oil, walnuts and omega-3 enriched eggs. [1] See oily fish, flaxseed, chia seeds and walnuts. A 2026 systematic review found vegetarian and especially vegan diets had lower blood EPA and DHA, and that algal DHA improved DHA status. [12]

Where to go next

Frequently asked questions

Do I need both omega-3 and omega-6?

Both are essential fat types, but the NHS says most people already get enough omega-6 and recommends paying more attention to omega-3 through fish. [1]

Is omega-9 essential?

Not in the sources we read. EFSA says that, strictly speaking, only LA is essential among the omega-6 fats, and it lists ALA as the essential omega-3. It does not list oleic acid as essential. [2]

How much omega-3 should I get?

It depends on the country and the guideline. The NHS advises two portions of fish a week with one oily; EFSA gives 250 mg a day of EPA plus DHA as an adequate intake for healthy adults and children. [6][7] A clinician can say what suits one person.

Can vegetarians get omega-3?

Plant foods provide ALA, and the NHS lists flaxseed oil, rapeseed oil, walnuts and omega-3 enriched eggs. [1] A systematic review found lower blood EPA and DHA in vegan diets. [12] See omega-3 for vegetarians.

Is "omega-3, 6, 9" in one capsule a good idea?

Proper evidence not found that the blend beats its parts. A PubMed search found only small trials of mixed products, such as a pilot in 31 preterm toddlers using a canola oil placebo and an open trial in 19 people with atopic dermatitis, which cannot separate the effect of each fat. [13][14] The NHS says most people already get enough omega-6. [1]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Safety
Fats in ordinary food are not a safety concern for most people. Concentrated oils are different: they can interact with medicines (including blood thinners), matter around surgery, and cause problems in people with fish or shellfish allergy. Talk to a clinician or pharmacist before starting one, especially in pregnancy, for children, or with kidney or liver conditions. See how interactions work and quality testing.
References
  1. NHS, Fat: the facts. Read 2026-10-22.
  2. EFSA NDA Panel, Labelling reference intake values for n-3 and n-6 polyunsaturated fatty acids, EFSA Journal 2009;1176 (copy of the opinion hosted by the EFSA Focal Point Bulgaria; efsa.europa.eu returned an access error). Read 2026-10-22.
  3. Berkowitz L et al. The controversial role of linoleic acid in cardiometabolic health: from molecular pathways to human studies. Front Nutr 2026. Read 2026-10-22.
  4. MedlinePlus, Omega-3 fats - Good for your heart. Read 2026-10-22.
  5. MedlinePlus, Facts about polyunsaturated fats. Read 2026-10-22.
  6. NHS, Fish and shellfish. Read 2026-10-22.
  7. EFSA, EFSA assesses safety of long-chain omega-3 fatty acids (2012 news story). Read 2026-10-22.
  8. NCCIH, Omega-3 Supplements: What You Need To Know. Updated November 2024. Read 2026-10-22.
  9. Abdelhamid AS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2018. Read 2026-10-22.
  10. Marklund M et al. Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality. Circulation 2019. Read 2026-10-22.
  11. Hooper L et al. Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2018. Read 2026-10-22.
  12. Chamorro R et al. Vegetarian diets and their effect on n-3 polyunsaturated fatty acids status in humans: systematic review. Lipids 2026. Read 2026-10-22.
  13. Effects of Omega-3-6-9 fatty acid supplementation on behavior and sleep in preterm toddlers with autism symptomatology: secondary analysis of a randomized clinical trial. Early Hum Dev 2022. PubMed. Read 2026-10-22.
  14. Open trial of supplements of omega 3 and 6 fatty acids, vitamins and minerals in atopic dermatitis. J Dermatolog Treat 2006. PubMed. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.