Omega-3
Omega-3s are a family of polyunsaturated fats the body needs for its cell membranes. Three matter in food: ALA from seeds, nuts, and plant oils, and EPA and DHA from fish and seafood.
1.1-1.6 ga day for adults, adequate intake (US), as ALA
250 mg of EPA and DHA combined a day (EFSA)
Upper limit · none set; EFSA saw no safety concern up to 5 g of EPA and DHA a day
- Most per 100 g 53.4g Flaxseed oil
- Most per portion 2.9g 1 fillet salmon
- Main sources Oily fish and chia, walnuts, and flaxseed for ALA
- Main types 3 ALA, EPA, and DHA
Daily amounts: US adequate intake for ALA, EFSA adequate intake for EPA and DHA. Food figures per 100 g from USDA FoodData Central.
Foods High in Omega-3
Ranked per 100 g, with what a usual portion gives, limited to 3 foods per category. Foods with a Caltide calorie page link to it.
F
Flaxseed oil
7.5 g in 1 tablespoon
53.4g / 100 g
F
Flax seeds (ground)
19.4g / 100 g
C
Chia seeds
2.1 g in 1 tablespoon
Nutrition facts
17.8g / 100 g
W
Walnut oil
1.5 g in 1 tablespoon
10.4g / 100 g
W
Walnuts
2.5 g in 1 handful
Nutrition facts
9.1g / 100 g
R
Rapeseed oil (canola)
1 g in 1 tablespoon
7.5g / 100 g
C
Caviar
1 g in 1 tablespoon
6.6g / 100 g
Per 100 g vs. a Usual Portion
Why the food that ranks first per 100 g can give less in a real serving.
| Food | Usual portion | Per 100 g | Per portion |
|---|---|---|---|
| Chia seeds | 1 tablespoon (12 g) | 17.8g | 2.1g |
| Walnuts | 1 handful (28 g) | 9.1g | 2.5g |
| Salmon | 1 fillet (125 g) | 2.3g | 2.9g |
| Sardines | 1 can (92 g) | 1.5g | 1.4g |
A tablespoon of chia, a handful of walnuts, and a salmon fillet land within a gram or so of each other in total omega-3. The difference is the kind: the seeds and nuts give only ALA, while most of the salmon's is EPA and DHA.
What Is Omega-3?
Omega-3 is a family name, not one nutrient. Every omega-3 fatty acid has its first double bond three carbons from the end of the chain, which is where the name comes from. The body cannot build that bond, so the whole family has to start from food.
The Three Main Omega-3s: ALA, EPA, and DHA
ALA (alpha-linolenic acid) is the short, 18-carbon plant omega-3 and the only one that is strictly essential. The body burns much of it for energy and turns a small share into the longer omega-3s.
EPA (eicosapentaenoic acid) has 20 carbons. Cells use it to make signaling molecules called eicosanoids, which take part in inflammation, blood clotting, and blood vessel tone. DHA (docosahexaenoic acid) has 22 carbons and is mainly structural: it is the most common omega-3 in the brain and in the retina of the eye.
Why an Omega-3 Total Can Be Misleading
A food label or a nutrition app that shows a single omega-3 figure adds all three together. Baked salmon in our library has 2.31 g of omega-3 per 100 g, of which 0.86 g is EPA and 1.13 g is DHA. Chia seeds have 17.8 g per 100 g, nearly eight times as much, and none of it is EPA or DHA.
So a day can hit a high omega-3 total from seeds alone and still contain no EPA or DHA at all. Conversion does not close that gap: the body makes only small amounts of EPA from ALA, and even less DHA.
Who Gets Enough Omega-3
US surveys find that most people get enough ALA, mainly from vegetable oils such as soybean and canola oil. EPA and DHA are the gap: they come almost only from fish and seafood, so intake follows how often someone eats fish. Vegans get EPA and DHA only from what their body converts or from algal oil.
For most adults, EFSA's 250 mg of EPA and DHA a day matches one or two servings of oily fish a week. Search the food library for fish to see each one's figures.
Common Omega-3 Mistakes
Counting flaxseed oil as fish oil. Flaxseed oil is rich in omega-3, but all of it is ALA. It covers the ALA need and does little for EPA and DHA.
Reading the oil weight, not the omega-3. A 1,000 mg fish oil softgel is the weight of the whole oil. In a common, unconcentrated product only about 300 mg of it is EPA and DHA.
How Much Omega-3 You Need
The US sets its amount as ALA, the essential omega-3. EFSA adds a separate amount for EPA and DHA.
| Age | Male | Female |
|---|---|---|
| 1 - 3 years | 0.7g | 0.7g |
| 4 - 8 years | 0.9g | 0.9g |
| 9 - 13 years | 1.2g | 1.0g |
| 14 - 18 years | 1.6g | 1.1g |
| 19+ years | 1.6g | 1.1g |
| Pregnancy | - | 1.4g |
| Breastfeeding | - | 1.3g |
Omega-3 Supplements
Supplements are a common source of EPA and DHA, especially for people who rarely eat fish. They differ in which omega-3s they carry and how much.
| Supplement | Gives | Worth knowing |
|---|---|---|
| Fish oil | EPA and DHA | The most common kind; the label lists EPA and DHA per serving |
| Cod liver oil | EPA and DHA | Also contains vitamins A and D, which count toward their own upper limits |
| Krill oil | EPA and DHA | Much of its omega-3 is bound to phospholipids rather than triglycerides |
| Algal oil | DHA, sometimes with EPA | Made from algae, so it suits people who eat no fish |
| Flaxseed oil | ALA | Adds ALA only; not a stand-in for EPA and DHA |
| Prescription omega-3 | EPA, or EPA and DHA | Concentrated medicines for very high triglycerides, used under a doctor's care |
How Much Omega-3 Is Too Much
EFSA found that up to 5 g of EPA and DHA a day from supplements raises no safety concern for adults. The US FDA advises no more than 3 g a day in total, with up to 2 g of it from supplements. Common side effects are a fishy aftertaste, heartburn, nausea, and loose stools.
Medicines That Interact With Omega-3
- Warfarin and other blood thinnershigh doses of omega-3 may add to their effect on bleeding
Ask a doctor or pharmacist before combining a supplement with a medicine.
Tracking Omega-3 in Caltide
- Logged automaticallyCaltide adds up the omega-3 in every food you log and shows it against the amount for your age and sex in the Nutrition tab, with ALA, EPA, and DHA listed under it.
- Supplements count tooAdd your fish oil or algal oil once with its EPA and DHA per serving as ingredients. Each day you tick it off, it counts toward your total.
Omega-3 Sources and References
The figures and claims on this page are checked against these sources. Food amounts come from USDA FoodData Central.
Questions About Omega-3
Adults need about 1.1 to 1.6 g of ALA a day (US adequate intake for women and men), plus 250 mg of EPA and DHA combined (EFSA). There is no single target for omega-3 as a whole.
In our food library, flaxseed oil: 53.4 g per 100 g. Flax seeds (ground) (19.4 g) and Chia seeds (17.8 g) come next. Seeds, nuts, and plant oils give ALA; fish give mostly EPA and DHA.
Not as a replacement. Plant omega-3 is ALA, and the body turns only a small share of it into EPA and DHA. ALA still counts toward its own daily need.
Yes. Fish oil, cod liver oil, krill oil, and algal oil add EPA and DHA, and flaxseed oil adds ALA. What counts is the EPA and DHA line on the label, not the weight of the oil in the capsule.
From supplements, yes. EFSA found no safety concern up to 5 g of EPA and DHA a day, and the US FDA advises no more than 2 g a day from supplements. High doses may add to the bleeding effect of blood thinners such as warfarin.
Baked salmon in our library has 2.3 g of omega-3 per 100 g, most of it EPA and DHA. Canned sardines have 1.5 g.
A true deficiency is rare in people who eat a normal diet. Its signs are rough, scaly skin and a red, swollen, itchy rash.
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