Omega-3-rich foods: what they contain and why omega-3 matters
Omega-3 polyunsaturated fatty acids are structural components of human cell membranes that modulate membrane fluidity, transport systems, and receptor activity [WHO]. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) function as biochemical precursors to specialized pro-resolving mediators and anti-inflammatory eicosanoids [ICMR-NIN]. DHA is concentrated within cerebral cortical gray matter and the photoreceptor membranes of the retina [WHO].
Last reviewed: 2026-09-05
How much omega-3 is in common foods
Values represent total omega-3 fatty acid content in grams per 100 grams of edible portion.
| Food | Omega-3 per 100 g | Source |
|---|---|---|
| Flaxseed oil (pure cold-pressed oil) | 53.3 g | USDA |
| Flaxseed (alsi) (raw whole seeds) | 22.81 g | USDA |
| Chia seeds (dried seeds) | 17.83 g | USDA |
| Walnut oil (pure cold-pressed oil) | 10.4 g | USDA |
| English walnuts (raw kernel) | 9.08 g | USDA |
| Rapeseed (canola) oil (refined oil) | 8.6 g | USDA |
| Soybean oil (pure salad oil) | 6.79 g | USDA |
| Mustard oil (cold-pressed seed oil) | 5.9 g | ICMR-NIN |
| Mackerel, Atlantic (cooked, dry heat) | 2.59 g | USDA |
| Salmon, Atlantic, farmed (cooked, dry heat) | 2.15 g | USDA |
| Herring, Atlantic (cooked, dry heat) | 2.13 g | USDA |
| Salmon, sockeye, wild (cooked, dry heat) | 1.48 g | USDA |
| Sardines, Atlantic (canned in oil, drained solids) | 1.48 g | USDA |
| Soybeans, mature (raw dry seeds) | 1.44 g | USDA |
| Hilsa (Tenualosa ilisha) (raw edible muscle) | 1.25 g | ICMR-NIN |
| Trout, rainbow, farmed (cooked, dry heat) | 1.06 g | USDA |
| Navy beans (raw dry seeds) | 0.62 g | USDA |
| Tofu, firm (prepared with calcium sulfate) | 0.58 g | USDA |
| Kidney beans (rajma) (raw dry seeds) | 0.57 g | USDA |
| Rohu (Labeo rohita) (raw edible muscle) | 0.38 g | ICMR-NIN |
| Cowpeas (lobia) (raw dry seeds) | 0.35 g | USDA |
| Catla (Gibelion catla) (raw edible muscle) | 0.28 g | ICMR-NIN |
| Edamame (frozen, prepared) | 0.28 g | USDA |
| Tuna, light (canned in water, drained solids) | 0.27 g | USDA |
| Spinach (raw mature leaves) | 0.14 g | USDA |
| Egg, whole (hard-boiled) | 0.11 g | USDA |
Vegetarian and vegan sources
Plant-based sources provide omega-3 exclusively as alpha-linolenic acid (ALA), with concentrated amounts present in whole flaxseed at 22.81 g per 100 g and chia seeds at 17.83 g per 100 g [USDA]. The human liver converts ALA into longer-chain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) via desaturase and elongase enzymes, with documented conversion rates of 5% to 8% for EPA and less than 1% to 5% for DHA [WHO].
Omega-3 and your blood test
Omega-3 fats have a documented relationship with blood triglycerides. If you have a lipid report, ReadMyReport explains what your triglyceride number means for you.
Frequently asked questions
- What is the structural difference between ALA, EPA, and DHA?
- Alpha-linolenic acid (ALA) is an 18-carbon chain containing 3 double bonds, whereas eicosapentaenoic acid (EPA) contains 20 carbons with 5 double bonds, and docosahexaenoic acid (DHA) contains 22 carbons with 6 double bonds [WHO].
- Which freshwater and marine fish in India contain omega-3 fatty acids?
- Raw hilsa muscle provides 1.25 g of total omega-3 fatty acids per 100 g, while Indian freshwater species such as rohu contain 0.38 g per 100 g and catla contains 0.28 g per 100 g [ICMR-NIN].
- How much alpha-linolenic acid is present in common culinary oils?
- Flaxseed oil contains 53.30 g of ALA per 100 g, rapeseed (canola) oil provides 8.60 g per 100 g, soybean oil contains 6.79 g per 100 g [USDA], and cold-pressed mustard oil provides 5.90 g per 100 g [ICMR-NIN].
- Can human tissues synthesize omega-3 fatty acids endogenously?
- Humans lack the delta-12 and delta-15 desaturase enzymes required to insert double bonds at the omega-3 and omega-6 positions of a hydrocarbon chain, classifying alpha-linolenic acid as an obligate dietary nutrient [WHO].
- What form of omega-3 is found in walnuts and whole seeds?
- Walnuts and oilseeds contain omega-3 exclusively in the form of ALA, with raw walnut kernels providing 9.08 g per 100 g and dried chia seeds providing 17.83 g per 100 g [USDA].
- Does thermal processing alter fatty acid quantification in fish?
- Dry-heat cooking causes moisture loss, concentrating total fatty acids by weight, resulting in cooked Atlantic mackerel containing 2.59 g of omega-3 per 100 g compared to 2.51 g per 100 g in raw Atlantic mackerel [USDA].
Sources
- USDA FoodData Central — USDA FoodData Central, Agricultural Research Service. https://fdc.nal.usda.gov/
- ICMR-NIN — Indian Food Composition Tables 2017, National Institute of Nutrition. https://www.nin.res.in/
- NIH ODS — NIH Office of Dietary Supplements — Omega-3 Fatty Acids, Fact Sheet. https://ods.od.nih.gov/