Nutrient glossary
What is omega-3?
Omega-3s are essential fats for heart, brain and eye health, richest in oily fish and, as ALA, in flax, chia and walnuts.
Reviewed 20 July 2026. General information, not medical advice.
The short version
The omega-3 family has a marine branch, EPA and DHA from oily fish, and a plant branch, ALA from flaxseed, chia, hemp and walnuts. EPA and DHA are the forms most tied to heart and brain outcomes; the body converts only a small fraction of ALA into them, which is why fish once or twice a week is the standard evidence-based advice.
If you do not eat fish, keeping plant omega-3 generous matters more, and algae oil is the direct plant source of DHA.
Daily reference
1.6 g a day
The reference used here is 1.6 g a day for men and 1.1 g for women, kept as a gentle aim-for since UK guidance pushes oily fish rather than a gram amount.
This is the fixed adult reference used across these pages. In the app, your amount adjusts to your body and way of eating.
Best food sources of omega-3
Full ranking| Food | Per serving | Per 100g |
|---|---|---|
| Chia Seeds | 4.3 g | 17.8 g |
| Salmon Fillet | 3.5 g | 2.3 g |
| Flaxseed (Linseed) | 3.2 g | 22.8 g |
| Hemp Seeds | 2.6 g | 8.7 g |
| Walnuts | 2.5 g | 9.1 g |
| Mackerel | 1.4 g | 1.3 g |
| Sardines (canned) | 1.4 g | 1.5 g |
| Rapeseed Oil | 1.3 g | 9.1 g |
Common questions
- What is the best source of omega-3?
- Oily fish: salmon, mackerel, sardines and trout. One portion of mackerel covers several days of the reference amount.
- Can vegans get enough omega-3?
- Yes, from flaxseed, chia, hemp and walnuts for ALA, plus an algae oil supplement if you want direct DHA.