Omega 3
Commonly described as ‘good fats’, essential lipids often added to foods and supplements.
Omega 3 are essential polyunsaturated fatty acids—principally alpha‑linolenic acid (ALA) and the long‑chain forms eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Present in oily fish, krill, flaxseed, rapeseed and certain nuts, these lipids contribute to cell membrane structure, provide an energy reserve and are commonly described as “good fats.” Uses and effects vary by individual, and dietary sources or supplements are often used when intake from food is insufficient.
Public guidance recognizes an intake of about 250 mg/day of EPA plus DHA to help maintain normal heart function, while ALA is recommended as an essential dietary fatty acid; supplements are available as fish oil, krill oil or plant‑based oils. Safety considerations include potential interactions with anticoagulant medications and recommendations to avoid routine supplement use in certain groups (for example people preparing for surgery, pregnant or breastfeeding women, and children unless advised). Mild side effects such as fishy breath or transient digestive upset have been reported, and very high intake may contribute to weight gain. Individual responses and optimal dosing can differ, and research continues to refine understanding of benefits and risks.
At a Glance
Omega 3 are essential polyunsaturated fatty acids found in oily fish, krill and certain plant oils such as flaxseed and rapeseed.
They are structural components of cell membranes and serve as an energy reserve and metabolic substrate. Dietary sources and supplements supply ALA, EPA and DHA, and uses and effects vary by individual.
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Origin & History
Omega 3 fatty acids occur naturally in marine ecosystems and in certain terrestrial plants. Major dietary sources include oily fish and krill as well as plant oils such as flaxseed and rapeseed, and nuts; these lipids are incorporated into cell membranes across many tissues and are obtained from both animal and plant origins.
Early scientific attention to omega 3 followed investigations of traditional diets among Arctic populations, where high consumption of fish attracted research interest. Recognition of these fatty acids as distinct from saturated fats emerged in the mid‑twentieth century and led to the development of fortified foods and concentrated supplements to address situations where dietary intake may be insufficient.
Composition & Active Compounds
Omega 3 oils are liquid, polyunsaturated fatty acids characterized by multiple carbon–carbon double bonds; chemically they include short‑chain ALA (C18H30O2) and the long‑chain EPA (C20H30O2) and DHA (C22H32O2). These constituents differ in chain length and degree of unsaturation and are significant because they are incorporated into cell membranes and act as essential dietary fatty acids involved in cardiovascular and brain tissue structure and function.
EPA and DHA are the key long‑chain omega‑3s most commonly concentrated in supplements such as fish oil.
- ALA: short‑chain plant omega‑3 found in flaxseed and rapeseed oils, essential dietary precursor to longer‑chain forms
- EPA: long‑chain marine omega‑3 found in fish and krill oils, associated with effects on lipid levels
- DHA: long‑chain marine omega‑3 concentrated in brain and retina tissues, important for structural cell function
Related Herbs
Properties & Effects
Omega 3 are essential polyunsaturated fatty acids traditionally known for supporting cardiovascular and brain health and for contributing to cell membrane integrity.
Evidence for cardiovascular support is among the most established uses of omega 3.
- Cardiovascular support: may support healthy heart function and help maintain normal blood pressure in people with hypertension.
- Improved lipid profile: may help reduce blood triglycerides and contribute to a healthier blood lipid profile.
- Mental health support: research suggests they may support mood and cognitive health and be beneficial in some cases of depression and cognitive decline.
- Anti-inflammatory effects: may help reduce certain inflammatory responses.
- Eye health: may contribute to retinal health and help in the prevention of age‑related macular degeneration.
Dosage & How to Use
Recommended intakes vary by fatty acid type; below are intake values reported in dietary guidance.
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| EPA (eicosapentaenoic acid) | 250 mg/day |
| DHA (docosahexaenoic acid) | 250 mg/day |
| Heart function | 250 mg/day of EPA and DHA |
Safety, Side Effects & Contraindications
Some people should avoid or limit omega 3 supplements and consult a healthcare professional before use; this is particularly important when other medical treatments are in place. Known mild side effects associated with fish‑derived omega 3 include a fishy odor on breath or urine and transient digestive symptoms such as nausea or diarrhea, and very high intake may contribute to weight gain.
Omega 3 can interact with blood‑thinning medications and may increase bleeding risk when taken in large amounts alongside anticoagulants; individuals preparing for surgery should also avoid high‑dose supplements unless instructed by a clinician. Uses and effects vary by individual, so anyone with health conditions or on regular medication should seek professional advice before starting supplements.
- Anticoagulant use or surgery: supplements are not recommended for people taking blood‑thinning medication or those due to undergo surgery unless advised by a clinician.
- Pregnancy and breastfeeding: routine use of omega‑3 supplements is not recommended for pregnant or lactating women without medical advice.
- Children: routine supplementation is not recommended for children unless specifically advised by a healthcare professional.
May interact with blood‑thinning medications and is not routinely recommended for pregnant or breastfeeding women or children; consult a healthcare professional before use.