Omega Fatty Acids Explained: Omega-3, Omega-6 and Omega-9
Plain-language guide to omega-3, omega-6 and omega-9 fats: which are essential, where they come from in food, and what the health agencies actually say about eating patterns.
Content last updated . This page has not been medically reviewed.
Overview
"Omega" is a family name for certain fats. Omega-3 and omega-6 fats are both types of polyunsaturated fat, and the NHS (UK) says some types of each cannot be made by the body, so small amounts must come from food. [1] MedlinePlus (US National Library of Medicine) calls them essential fatty acids and says the body needs them for brain function and cell growth. [2] This page explains the terms. The individual products are covered in the other guides in Omega Fatty Acids.The three "omega" names
| Name | What the sources say | Where it is found |
|---|---|---|
| Omega-3 | A type of polyunsaturated fat; the body does not make it on its own and needs it from the diet. [3] | Oily fish, and plant sources such as flaxseed, walnuts, chia and rapeseed oil. [1][4] |
| Omega-6 | The second main type of polyunsaturated fat. The NHS says most people already get enough in their diet. [1] | Vegetable oils such as rapeseed, corn and sunflower, and nuts such as walnuts, almonds and cashews. [1] |
| Omega-9 | Proper evidence not found. We did not find an NHS, MedlinePlus or NCCIH page that defines omega-9 or reviews omega-9 supplements. | The NHS describes monounsaturated fats (the group usually linked with this label) in olive oil, rapeseed oil, avocados and some nuts. [1] |
Evidence labels used in this section: established nutritional role, evidence in adequately nourished people, promising but limited, mixed, insufficient evidence and marketing claim. Omega-3 and omega-6 as dietary needs sit in the first group. Specific supplement uses are judged one by one in Omega-3 evidence by use.
Essential or not
Essential means the body cannot make enough of it, so it has to be eaten. [2] The NHS wording is careful: it says "some types" of omega-3 and omega-6 fats cannot be made by the body. [1] No agency page we read gives a single daily number for omega-3 in the US or UK. One European figure exists: the European Food Safety Authority (EFSA) set an adequate intake of 250 mg a day of EPA plus DHA for general cardiovascular health in adults and children. [5] That is a European reference, not a universal target. See RDA, AI, DV and UL for what these terms mean.Omega-3 types, briefly
Most research focuses on EPA and DHA, found in seafood and fish oil. ALA is a plant omega-3 found in flaxseed, soybean and canola oils, chia seeds and walnuts. [6] The three are not interchangeable: see ALA, EPA and DHA.Food sources and eating patterns
- Oily fish. The NHS advises at least two portions of fish a week, including one of oily fish, and says oily fish is particularly high in long-chain omega-3. [7]
- US guidance. NCCIH cites the Dietary Guidelines for Americans 2020 to 2025, which recommend adults eat 8 ounces or more of a variety of seafood a week. [6]
- Plant foods. The NHS lists flaxseed (linseed) oil, rapeseed oil, walnuts and omega-3 enriched eggs as options for vegetarians, and ground linseed, chia seeds, hemp seeds and walnuts for vegans. [1][4] See oily fish, flaxseed and chia seeds.
- Fats overall. MedlinePlus says eating moderate amounts of polyunsaturated and monounsaturated fat in place of saturated and trans fat can benefit health. [2]
Food or supplement
NCCIH says that for some conditions the evidence for benefit from seafood is stronger than for omega-3 supplements, and that people who eat seafood tend to have healthier lifestyles overall, so the fish effect cannot be pinned on one nutrient. [6] For a food-first way of thinking, see Do I need a supplement?Safety
Fats in food are not a safety concern for most people. Concentrated oils are different: they can interact with medicines and some carry extra vitamins. Start with omega-3 safety and interactions and how interactions work.Frequently asked questions
Do I need both omega-3 and omega-6?
Yes, both are essential fat types, but the NHS says most people already get enough omega-6 and advises more attention to omega-3 through fish. [1]
Is omega-9 essential?
Proper evidence not found in the agency sources we checked; none of them defines omega-9 as an essential nutrient. The NHS describes monounsaturated fats in olive oil and avocados as helping protect the heart. [1]
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. [7][5]
Can vegetarians get omega-3?
Plant sources provide ALA. A systematic review found vegetarian and especially vegan diets had lower blood EPA and DHA, and that algal DHA improved DHA status. [8]
References
- NHS, Fat: the facts. Read 2026-10-22.
- MedlinePlus, Facts about polyunsaturated fats. Read 2026-10-22.
- MedlinePlus, Omega-3 fats - Good for your heart. Read 2026-10-22.
- NHS, The vegan diet. Read 2026-10-22.
- EFSA, EFSA assesses safety of long-chain omega-3 fatty acids (2012 news story). Read 2026-10-22.
- NCCIH, Omega-3 Supplements: What You Need To Know. Read 2026-10-22.
- NHS, Fish and shellfish. Read 2026-10-22.
- 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.