Dietary Sources of Omega-3 Fatty Acids (2025)

As for saturated and monounsaturated fatty acids, the omega-6 and omega-3 polyunsaturated fatty acids (PUFA) are chemically linked to fat structures known as triglycerides in the various foods and oils that are consumed. The natural triglyceride or fat structure consists of a 3-carbon glycerol backbone onto which 3 long-chain fatty acids of varying types and structures are linked or 'esterified'. These are hydrolyzed by enzymes and digested in the small intestine thereby providing for their absorption, transport in the blood, and assimilation into cells and body tissues. Table 1 lists some common food sources of both the omega-6 and omega-3 fatty acids as found in a typical North American diet.

Fatty AcidFood Sources(i) Omega-6 TypesLA, linoleic acid
(18:2 n-6)Vegetable oils (corn, safflower, sunflower, soybean), animal meatsAA, arachidonic acid
(20:4 n-6)

Animal sources only (meat, eggs)

(ii) Omega-3 TypesALA , (LNA) alpha-linolenic acid
(18:3 n-3)Flaxseed, canola oil, English walnuts, specialty eggsEPA, eicosapentaenoic acid
(20:5 n-3)Fish, fish oils, marine sourcesDHA, docosahexaenoic acid
(22:6 n-3)Fish, fish oils, specialty egg/dairy products

In view of the high intake of vegetable oils containing n-6 PUFA directly and via various processed food products including meats, a typical diet contains 8-15 g/day of LA (omega-6) but much lower intakes of the omega-3 types. ALA consumption ranges from approximately 1.3-2.0 g/day or approximately 0.6% of total energy intake. In contrast to the considerable intake of ALA from plant sources, the intake of fish/fish oil-derived DHA/EPA (combined) represents approximately 0.13-0.15 g/day (130-150 mg/day) which is 0.05% of total energy intake or about 1/10 of the intake of ALA. The vast majority of the DHA plus EPA as consumed in the North American diet is from fish/fish oils with much smaller amounts from selected animal sources (e.g., eggs, some meat sources) and none from plant food/oils regardless of their ALA levels. The overall ratio of omega-6:omega-3 fatty acids in the current North American diet ranges from 6:1 to approximately 10:1.

Selected food sources of a-linolenic acid (ALA) are given in Table 2. Some of the common plant oils have significant levels of ALA - e.g., 7% by weight in soybean oil, 10% in canola oil, and approximately 20% in hemp oil. Much higher amounts are found in the oils from flax, perilla (Japan and elsewhere), and chia (Argentina and elsewhere) with approximately 50-60% of the fatty acids being in the form of ALA.

Data from Kris-Etherton et al. (2000)

Recently, strains of flaxseed oils have become available which contain approximately 70% by weight of the oil as ALA which is significantly higher than the 50-55% found in conventional flax oil varieties. Table 3 gives the levels of EPA plus DHA in a few selected fish and seafood.

Source
(100 g portion)DHA + EPA
(g)FishAnchovy, European, raw1.449Carp, cooked, dry heat0.451Catfish, channel, farmed, cooked, dry heat0.177Cod, Atlantic , cooked, dry heat0.158Eel, mixed species, cooked, dry heat0.189Flatfish (flounder and sole), cooked, dry heat0.501Haddock, cooked, dry heat0.238Halibut, Atlantic and Pacific, cooked, dry heat0.465Herring, Atlantic , cooked, dry heat2.014Mackerel, Pacific and jack, mixed species, cooked, dry heat1.848Mullet, striped, cooked, dry heat0.328Perch, mixed species, cooked, dry heat0.324Pike, northern, cooked, dry heat0.137Pollock, Atlantic , cooked, dry heat0.542Salmon, Atlantic , farmed, cooked, dry heat2.147Sardine, Atlantic , canned in oil, drained solids with bone0.982Sea bass, mixed species, cooked, dry heat0.762Shark, mixed species, raw0.843Snapper, mixed species, cooked, dry heat0.321Swordfish, cooked, dry heat0.819Trout, mixed species, cooked, dry heat0.936Tuna, skipjack, fresh, cooked, dry heat0.328Whiting, mixed species, cooked, dry heat0.518CrustaceansCrab, Alaska king, cooked, moist heat0.413Shrimp, mixed species, cooked, moist heat0.315Spiny lobster, mixed species, cooked, moist heat0.480MollusksClam, mixed species, cooked, moist heat0.284Conch, baked or broiled0.120Mussel, blue, cooked, moist heat0.782Octopus, common, cooked, moist heat0.314Oyster, eastern, farmed, cooked, dry heat0.440Scallop, mixed species, cooked, breaded and fried0.180

It should be noted that algal oils have recently become available as a source of DHA (free of EPA) for infant formulas and other functional food fortification. There has been a marked increase in the use of high quality liquid fish oils containing DHA plus EPA as ingredients in a wide variety of functional foods (e.g., liquid eggs). Furthermore, stable and microencapsulated forms of DHA plus EPA (with varying amounts and ratios of DHA:EPA) have been utilized in a whole plethora of processed food formulations (breads, yogurts, snack foods, etc). In view of the resistance of the North American and other populations to increase fish consumption as a source of DHA plus EPA for health despite recommendations by health care agencies and professionals, it is apparent that functional foods will became an ever-increasing source of these important nutrients in the omega-3 family.

Dietary Sources of Omega-3 Fatty Acids (2025)
Top Articles
Latest Posts
Recommended Articles
Article information

Author: Cheryll Lueilwitz

Last Updated:

Views: 5613

Rating: 4.3 / 5 (74 voted)

Reviews: 81% of readers found this page helpful

Author information

Name: Cheryll Lueilwitz

Birthday: 1997-12-23

Address: 4653 O'Kon Hill, Lake Juanstad, AR 65469

Phone: +494124489301

Job: Marketing Representative

Hobby: Reading, Ice skating, Foraging, BASE jumping, Hiking, Skateboarding, Kayaking

Introduction: My name is Cheryll Lueilwitz, I am a sparkling, clean, super, lucky, joyous, outstanding, lucky person who loves writing and wants to share my knowledge and understanding with you.