Omega-3 fatty acid
|Types of fats in food|
Omega-3 fatty acids (also called ω-3 fatty acids or n-3 fatty acids) refer to a group of three fats called ALA (found in plant oils), EPA, and DHA (both commonly found in marine oils). Common sources of animal omega-3 EPA and DHA fatty acids include fish oils, egg oil, squid oils, krill oil, while some plant oils contain the omega 3 ALA fatty acid such as seabuckthorn seed and berry oils, algal oil, flaxseed oil, Sacha Inchi oil, Echium oil, and hemp oil.
Omega-3 fatty acids are vital for normal metabolism but some of the potential health benefits of supplementation are controversial. Omega-3s are considered essential fatty acids, meaning that they cannot be synthesized by the human body -except that mammals have a limited ability, when the diet includes the shorter-chained omega-3 fatty acid ALA (α-linolenic acid, 18 carbons and 3 double bonds), to form the more important long-chain omega-3 fatty acids, EPA (eicosapentaenoic acid, 20 carbons and 5 double bonds) and then from EPA, the most crucial, DHA (docosahexaenoic acid, 22 carbons and 6 double bonds) with even greater inefficiency. The ability to make the longer-chained omega-3 fatty acids from ALA may also be impaired in aging. In foods exposed to air, unsaturated fatty acids are vulnerable to oxidation and rancidity. Fish are much more efficient than mammals at converting the ALA to the EPA and DHA omega-3 fatty acids.
Omega-3 fatty acids are polyunsaturated fatty acids with a double bond (C=C) at the third carbon atom from the end of the carbon chain. The fatty acids have two ends, the carboxylic acid (-COOH) end, which is considered the beginning of the chain, thus "alpha", and the methyl (CH3) end, which is considered the "tail" of the chain, thus "omega." The nomenclature of the fatty acid is taken from the location of the first double bond, counted from the methyl end, that is, the omega (ω-) or the n- end.
- 1 Health effects
- 2 Chemistry
- 3 Mechanism of action
- 4 History
- 5 Dietary sources
- 6 References
- 7 Further reading
- 8 External links
Supplementation does not appear to be associated with a lower risk of all-cause mortality.
A 2006 review concluded that there was no link between omega-3 fatty acids consumption and cancer. This is similar to the findings of a review of studies up to February 2002 that failed to find clear effects of long and shorter chain omega-3 fats on total risk of death, combined cardiovascular events and cancer. In those with advanced cancer and cachexia, omega-3 fatty acids supplements may be of benefit, improving appetite, weight, and quality of life. There is tentative evidence that marine omega-3 polyunsaturated fatty acids reduce the risk of breast cancer but this is not conclusive.
The effect of consumption on prostate cancer is not conclusive. There is a decreased risk with higher blood levels of DPA, but an increased risk of more aggressive prostate cancer with higher blood levels of combined EPA and DHA (found in fatty fish oil).
Evidence does not support a beneficial role for omega-3 fatty acid supplementation in preventing cardiovascular disease (including myocardial infarction and sudden cardiac death) or stroke. Fish oil supplementation has not been shown to benefit revascularization or arrythmia and has no effect on heart failure admission rates. Eating a diet high in fish that contain long chain omega-3 fatty acids does appear to decrease the risk of stroke.
Omega-3 fatty acids also have mild antihypertensive effects. When subjects consumed omega-3 fatty acids from oily fish on a regular basis, their systolic blood pressure was lowered by about 3.5–5.5 mmHg. The 18 carbon α-linolenic acid (ALA) has not been shown to have the same cardiovascular benefits that DHA or EPA may have.
Some evidence suggests that people with certain circulatory problems, such as varicose veins, may benefit from the consumption of EPA and DHA, which may stimulate blood circulation, increase the breakdown of fibrin, a compound involved in clot and scar formation, and, in addition, may reduce blood pressure. Evidently, omega-3 fatty acids reduce blood triglyceride levels, and regular intake may reduce the risk of secondary and primary heart attack. ALA does not confer the cardiovascular health benefits of EPA and DHA.
Large amounts may increase the risk of hemorrhagic stroke (see below); lower amounts are not related to this risk; 3 grams of total EPA/DHA daily are generally recognized as safe (GRAS) with no increased risk of bleeding involved and many studies used substantially higher doses without major side effects (for example: 4.4 grams EPA/2.2 grams DHA in 2003 study).
Although not confirmed as an approved health claim, current research suggests that the anti-inflammatory activity of long-chain omega-3 fatty acids may translate into clinical effects. For example, there is evidence that rheumatoid arthritis sufferers taking long-chain omega-3 fatty acids from sources such as fish have reduced pain compared to those receiving standard NSAIDs. Some potential benefits have been reported in conditions such as rheumatoid arthritis.
Although not supported by current scientific evidence as a primary treatment for ADHD, autism spectrum disorders, and other developmental differences, omega-3 fatty acids have gained popularity for children with these conditions.
Omega-3 fatty acids offer a promising complementary approach to standard treatments for ADHD and developmental coordination disorder. Fish oils appear to reduce ADHD-related symptoms in some children. A randomized, controlled trial has suggested that "fatty acid supplementation may offer a safe efficacious treatment option for educational and behavioral problems among children with DCD" .
There is not enough scientific evidence to support the effectiveness of omega-3 fatty acids for autism spectrum disorders.
The brain and cognitive abilities
The DHA obtained through the consumption of polyunsaturated fatty acids has not been found to be positively associated with cognitive performance.[not in citation given] In addition, DHA is vital for the grey matter structure of the human brain, as well as retinal stimulation and neurotransmission.
Though there is some evidence that omega-3 fatty acids are related to a variety of mental disorders, they may tentatively be useful as an add-on for the treatment of depression associated with bipolar disorder and there is preliminary evidence that EPA supplementation is helpful in cases of depression. There is, however, a significant difficulty in interpreting the literature due to participant recall and systematic differences in diets.
Epidemiological studies suggest that consumption of omega-3 fatty acids can reduce the risk of dementia, but evidence of a treatment effect in dementia patients is inconclusive. However, clinical evidence suggests benefits of treatment specifically in patients who show signs of cognitive decline but who are not sufficiently impaired to meet criteria for dementia.
In a letter published October 31, 2000,[dated info] the United States Food and Drug Administration Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements noted that known or suspected risks of EPA and DHA consumed in excess of 3 grams per day may include the possibility of:
- Increased incidence of bleeding
- Hemorrhagic stroke
- Oxidation of omega-3 fatty acids, forming biologically active oxidation products
- Increased levels of low-density lipoproteins (LDL) cholesterol or apoproteins associated with LDL cholesterol among diabetics and hyperlipidemics
- Reduced glycemic control among diabetics
Omega-3 fatty acids that are important in human physiology are α-linolenic acid (18:3, n-3; ALA), eicosapentaenoic acid (20:5, n-3; EPA), and docosahexaenoic acid (22:6, n-3; DHA). These three polyunsaturates have either 3, 5, or 6 double bonds in a carbon chain of 18, 20, or 22 carbon atoms, respectively. As with most naturally-produced fatty acids, all double bonds are in the cis-configuration, in other words, the two hydrogen atoms are on the same side of the double bond; and the double bonds are interrupted by methylene bridges (-CH
2-), so that there are two single bonds between each pair of adjacent double bonds.
List of omega-3 fatty acids
This table lists several different names for the most common omega-3 fatty acids found in nature.
|Common name||Lipid name||Chemical name|
|Hexadecatrienoic acid (HTA)||16:3 (n-3)||all-cis-7,10,13-hexadecatrienoic acid|
|α-Linolenic acid (ALA)||18:3 (n-3)||all-cis-9,12,15-octadecatrienoic acid|
|Stearidonic acid (SDA)||18:4 (n-3)||all-cis-6,9,12,15-octadecatetraenoic acid|
|Eicosatrienoic acid (ETE)||20:3 (n-3)||all-cis-11,14,17-eicosatrienoic acid|
|Eicosatetraenoic acid (ETA)||20:4 (n-3)||all-cis-8,11,14,17-eicosatetraenoic acid|
|Eicosapentaenoic acid (EPA)||20:5 (n-3)||all-cis-5,8,11,14,17-eicosapentaenoic acid|
|Heneicosapentaenoic acid (HPA)||21:5 (n-3)||all-cis-6,9,12,15,18-heneicosapentaenoic acid|
|Docosapentaenoic acid (DPA),
|22:5 (n-3)||all-cis-7,10,13,16,19-docosapentaenoic acid|
|Docosahexaenoic acid (DHA)||22:6 (n-3)||all-cis-4,7,10,13,16,19-docosahexaenoic acid|
|Tetracosapentaenoic acid||24:5 (n-3)||all-cis-9,12,15,18,21-tetracosapentaenoic acid|
|Tetracosahexaenoic acid (Nisinic acid)||24:6 (n-3)||all-cis-6,9,12,15,18,21-tetracosahexaenoic acid|
Mechanism of action
The 'essential' fatty acids were given their name when researchers found that they are essential to normal growth in young children and animals, though the modern definition of 'essential' is more strict. A small amount of omega-3 in the diet (~1% of total calories) enabled normal growth, and increasing the amount had little to no additional effect on growth.
Likewise, researchers found that omega-6 fatty acids (such as γ-linolenic acid and arachidonic acid) play a similar role in normal growth. However, they also found that omega-6 was "better" at supporting dermal integrity, renal function, and parturition. These preliminary findings led researchers to concentrate their studies on omega-6, and it is only in recent decades that omega-3 has become of interest.
In 1964, it was discovered that enzymes found in sheep tissues convert omega-6 arachidonic acid into the inflammatory agent called prostaglandin E2, which both causes the sensation of pain and expedites healing and immune response in traumatized and infected tissues. By 1979, more of what are now known as eicosanoids were discovered: thromboxanes, prostacyclins, and the leukotrienes. The eicosanoids, which have important biological functions, typically have a short active lifetime in the body, starting with synthesis from fatty acids and ending with metabolism by enzymes. However, if the rate of synthesis exceeds the rate of metabolism, the excess eicosanoids may have deleterious effects. Researchers found that certain omega-3 fatty acids are also converted into eicosanoids, but at a much slower rate. Eicosanoids made from omega-3 fatty acids are often referred to as anti-inflammatory, but in fact they are just less inflammatory than those made from omega-6 fats. If both omega-3 and omega-6 fatty acids are present, they will "compete" to be transformed, so the ratio of long-chain omega-3:omega-6 fatty acids directly affects the type of eicosanoids that are produced.
This competition was recognized as important when it was found that thromboxane is a factor in the clumping of platelets, which can both cause death by thrombosis and prevent death by bleeding. Likewise, the leukotrienes were found to be important in immune/inflammatory-system response, and therefore relevant to arthritis, lupus, asthma, and recovery from infections. These discoveries led to greater interest in finding ways to control the synthesis of omega-6 eicosanoids. The simplest way would be by consuming more omega-3 and fewer omega-6 fatty acids.
They are required during the prenatal period for the formation of synapses and cell membranes. These processes are also essential in postnatal human development for injury response of the central nervous system and retinal stimulation.
Conversion efficiency of ALA to EPA and DHA
Men's bodies convert short-chain omega-3 fatty acids to long-chain forms (EPA, DHA) with an efficiency below 5%. The omega-3 conversion efficiency is greater in women, but less well-studied.
These conversions occur competitively with omega-6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. Both the omega-3 α-linolenic acid and omega-6 linoleic acid must be obtained from food. Synthesis of the longer omega-3 fatty acids from linolenic acid within the body is competitively slowed by the omega-6 analogues. Thus, accumulation of long-chain omega-3 fatty acids in tissues is more effective when they are obtained directly from food or when competing amounts of omega-6 analogs do not greatly exceed the amounts of omega-3.
The conversion of ALA to EPA and further to DHA in humans has been reported to be limited, but varies with individuals. Women have higher ALA conversion efficiency than men, which is presumed to be due to the lower rate of use of dietary ALA for beta-oxidation. This suggests that biological engineering of ALA conversion efficiency is possible. Goyens et al. argue that it is the absolute amount of ALA, rather than the ratio of omega-3 and omega-6 fatty acids, that controls the conversion efficiency.
The omega-6 to omega-3 ratio
Some older clinical studies indicate that the ingested ratio of omega-6 to omega-3 (especially linoleic vs alpha-linolenic) fatty acids is important to maintaining cardiovascular health. However, three studies published in 2005, 2007 and 2008, including a randomized controlled trial, found that while omega-3 polyunsaturated fatty acids are extremely beneficial in preventing heart disease in humans, the levels of omega-6 polyunsaturated fatty acids (and therefore the ratios) did not matter.
Both omega-6 and omega-3 fatty acids are essential; i.e., humans must consume them in their diet. Omega-6 and omega-3 eighteen-carbon polyunsaturated fatty acids compete for the same metabolic enzymes, thus the omega-6:omega-3 ratio of ingested fatty acids has significant influence on the ratio and rate of production of eicosanoids, a group of hormones intimately involved in the body's inflammatory and homeostatic processes which includes the prostaglandins, leukotrienes, and thromboxanes, among others. Altering this ratio can change the body's metabolic and inflammatory state. In general, grass-fed animals accumulate more omega-3 than do grain-fed animals, which accumulate relatively more omega-6. Metabolites of omega-6 are more inflammatory (esp. arachidonic acid) than those of omega-3. This necessitates that omega-6 and omega-3 be consumed in a balanced proportion; healthy ratios of omega-6:omega-3, according to some authors, range from 1:1 to 1:4 (an individual needs more omega-3 than omega-6). Other authors believe that ratio 4:1 (when the amount of omega-6 is only 4 times greater than that of omega-3) is already healthy. Studies suggest the evolutionary human diet, rich in game animals, seafood, and other sources of omega-3, may have provided such a ratio.
Typical Western diets provide ratios of between 10:1 and 30:1 (i.e., dramatically higher levels of omega-6 than omega-3). The ratios of omega-6 to omega-3 fatty acids in some common vegetable oils are: canola 2:1, hemp 2-3:1, soybean 7:1, olive 3–13:1, sunflower (no omega-3), flax 1:3, cottonseed (almost no omega-3), peanut (no omega-3), grapeseed oil (almost no omega-3) and corn oil 46:1 ratio of omega-6 to omega-3.
On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to EPA and DHA omega-3 fatty acids, stating, "supportive but not conclusive research shows that consumption of EPA and DHA [omega-3] fatty acids may reduce the risk of coronary heart disease." This updated and modified their health risk advice letter of 2001 (see below). As of this writing, regulatory agencies[who?] do not accept that there is sufficient evidence for any of the suggested benefits of DHA and EPA other than for cardiovascular health, and further claims should be treated with caution.
The Canadian Government has recognized the importance of DHA omega-3 and permits the following biological role claim for DHA: "DHA, an omega-3 fatty acid, supports the normal development of the brain, eyes and nerves."
|Common name||grams omega-3|
|Tuna (canned, light)||0.17–0.24|
|Hoki (blue grenadier)||0.41|
|Blue eye cod||0.31|
|Sydney rock oysters||0.30|
|Eggs, large regular||0.109|
|Strawberry or Kiwifruit||0.10-0.20|
|Giant tiger prawn||0.100|
|Lean red meat||0.031|
|Cereals, rice, pasta, etc.||0.00|
As macronutrients, fats are not assigned Dietary Reference Intakes. Macronutrients have acceptable intake (AI) levels and acceptable macronutrient distribution ranges (AMDRs) instead of RDAs. The AI for omega-3 is 1.6 grams/day for men and 1.1 grams/day for women, while the AMDR is 0.6% to 1.2% of total energy.
A growing body of literature suggests that higher intakes of α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) may afford some degree of protection against coronary disease. Because the physiological potency of EPA and DHA is much greater than that of ALA, it is not possible to estimate one AMDR for all omega-3 fatty acids. Approximately 10 percent of the AMDR can be consumed as EPA and/or DHA." There was insufficient evidence as of 2005 to set an upper tolerable limit for omega-3 fatty acids.
Heavy metal poisoning by the body's accumulation of traces of heavy metals, in particular mercury, lead, nickel, arsenic, and cadmium, is a possible risk from consuming fish oil supplements.[medical citation needed] Also, other contaminants (PCBs, furans, dioxins, and PBDEs) might be found, especially in less-refined fish oil supplements. In reality, however, heavy metal toxicity from consuming fish oil supplements is highly unlikely, because heavy metals selectively bind with protein in the fish flesh rather than accumulate in the oil. An independent test in 2005 of 44 fish oils on the US market found all of the products passed safety standards for potential contaminants.[unreliable source?]
The FDA has advised that adults can safely consume a total of 3 grams per day of combined DHA and EPA, with no more than 2 g per day coming from dietary supplements.
Throughout their history, the Council for Responsible Nutrition and the World Health Organization have published acceptable standards regarding contaminants in fish oil. The most stringent current standard is the International Fish Oils Standard.[non-primary source needed] Fish oils that are molecularly distilled under vacuum typically make this highest-grade, and have measurable levels of contaminants (measured parts per billion and parts per trillion).
A recent trend has been to fortify food with omega-3 fatty acid supplements. Global food companies have launched omega-3 fatty acid fortified bread, mayonnaise, pizza, yogurt, orange juice, children's pasta, milk, eggs, popcorn, confections, and infant formula.
The American Heart Association has set up dietary recommendations for EPA and DHA due to their cardiovascular benefits: Individuals with no history of coronary heart disease or myocardial infarction should consume oily fish or fish oils two times per week; those having been diagnosed with coronary heart disease after infarction should consume 1 g EPA and DHA per day from oily fish or supplements; those wishing to lower blood triglycerides should consume 2–4 g of EPA and DHA per day in the form of supplements.[dated info]
The most widely available dietary source of EPA and DHA is cold water oily fish, such as salmon, herring, mackerel, anchovies, and sardines. Oils from these fish have a profile of around seven times as much omega-3 as omega-6. Other oily fish, such as tuna, also contain n-3 in somewhat lesser amounts. Consumers of oily fish should be aware of the potential presence of heavy metals and fat-soluble pollutants like PCBs and dioxins, which are known to accumulate up the food chain. After extensive review, researchers from Harvard's School of Public Health in the Journal of the American Medical Association (2006) reported that the benefits of fish intake generally far outweigh the potential risks. Although fish are a dietary source of omega-3 fatty acids, fish do not synthesize them; they obtain them from the algae (microalgae in particular) or plankton in their diets.
Marine and freshwater fish oil vary in content of arachidonic acid, EPA and DHA. They also differ in their effects on organ lipids. Not all forms of fish oil may be equally digestible. Of four studies that compare bioavailability of the glyceryl ester form of fish oil vs. the ethyl ester form, two have concluded the natural glyceryl ester form is better, and the other two studies did not find a significant difference. No studies have shown the ethyl ester form to be superior, although it is cheaper to manufacture.
Krill oil is a newly[when?] discovered source of omega-3 fatty acids. Various claims are made in support of krill oil as a superior source of omega-3 fatty acids. The effect of krill oil, at a lower dose of EPA + DHA (62.8%), was demonstrated to be similar to that of fish oil.
These tables are incomplete.
|Common name||Alternative name||Linnaean name||% ALA|
|Chia seed||chia sage||Salvia hispanica||58|
|Flax||linseed||Linum usitatissimum||53 – 59|
|Black raspberry||Rubus occidentalis||33|
|Canola||9 – 11|
|Common name||Linnaean name||% ALA|
|Persian walnuts||Juglans regia||6.3|
|Pecan nuts||Carya illinoinensis||0.6|
|Hazel nuts||Corylus avellana||0.1|
Flaxseed (or linseed) (Linum usitatissimum) and its oil are perhaps the most widely available botanical source of the omega-3 fatty acid ALA. Flaxseed oil consists of approximately 55% ALA, which makes it six times richer than most fish oils in omega-3 fatty acids. A portion of this is converted by the body to EPA and DHA, though the actual converted percentage may differ between men and women.
Eggs produced by hens fed a diet of greens and insects contain higher levels of omega-3 fatty acids than those produced by chickens fed corn or soybeans. In addition to feeding chickens insects and greens, fish oils may be added to their diets to increase the omega-3 fatty acid concentrations in eggs.
The addition of flax and canola seeds to the diets of chickens, both good sources of alpha-linolenic acid, increases the omega-3 content of the eggs, predominantly DHA.
The addition of green algae or seaweed to the diets boosts the content of DHA and EPA content, which are the forms of omega-3 approved by the FDA for medical claims. A common consumer complaint is "Omega-3 eggs can sometimes have a fishy taste if the hens are fed marine oils."
Omega 3 fatty acids are formed in the chloroplasts of green leaves and algae. While seaweeds and algae are the source of omega 3 fatty acids present in fish, grass is the source of omega 3 fatty acids present in grass fed animals. When cattle are taken off omega 3 fatty acid rich grass and shipped to a feedlot to be fattened on omega 3 fatty acid deficient grain, they begin losing their store of this beneficial fat. Each day that an animal spends in the feedlot, the amount of omega 3 fatty acids in its meat is diminished.
In a 2009 joint study by the USDA and researchers at Clemson University in South Carolina, grass-fed beef was compared with grain-finished beef. The researchers found that grass-finished beef is higher in moisture content, 42.5% lower total lipid content, 54% lower in total fatty acids, 54% higher in beta-carotene, 288% higher in vitamin E (alpha-tocopherol), higher in the B-vitamins thiamin and riboflavin, higher in the minerals calcium, magnesium, and potassium, 193% higher in total omega-3s, 117% higher in CLA (cis-9 trans-11, which is a potential cancer fighter), 90% higher in vaccenic acid (which can be transformed into CLA), lower in the saturated fats linked with heart disease, and has a healthier ratio of omega-6 to omega-3 fatty acids (1.65 vs 4.84). Protein and cholesterol content were equal.
In most countries, commercially available lamb is typically grass-fed, and thus higher in omega-3 than other grain-fed or grain-finished meat sources. In the United States, lamb is often finished (i.e., fattened before slaughter) with grain, resulting in lower omega-3.
Mammalian brains and eyes
The brains and eyes of mammals are extremely rich in DHA as well as other omega-3 fatty acids. DHA is a major structural component of the mammalian brain, and is in fact the most abundant omega-3 fatty acid in the brain.
Seal oil is a source of EPA, DPA, and DHA. According to Health Canada, it helps to support the development of the brain, eyes and nerves in children up to 12 years of age. However, like all seal products, it is not allowed for import into the European Union.
In 2006 the Journal of Dairy Science published a study entitled, "The Linear Relationship between the Proportion of Fresh Grass in the Cow Diet, Milk Fatty Acid Composition, and Butter Properties". The study found that butter made from the milk of grass fed cows contains substantially more CLA, vitamin E, beta-carotene, and omega-3 fatty acids than butter made from the milk of cows that have limited access to pasture. It was also found that the more fresh pasture in the cow’s diet, the softer the butter.
- "Related terms". Omega-3 fatty acids, fish oil, alpha-linolenic acid. Mayo Clinic. Retrieved June 20, 2012.
- Freemantle, E.; Vandal, M. N.; Tremblay-Mercier, J.; Tremblay, S. B.; Blachère, J. C.; Bégin, M. E.; Thomas Brenna, J.; Windust, A.; Cunnane, S. C. (2006). "Omega-3 fatty acids, energy substrates, and brain function during aging". Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (3): 213. doi:10.1016/j.plefa.2006.05.011.
- Gao, F.; Taha, A. Y.; Ma, K.; Chang, L.; Kiesewetter, D.; Rapoport, S. I. (2012). "Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver". AGE. doi:10.1007/s11357-012-9390-1. PMID 22388930.
- Chaiyasit, W.; Elias, R. J.; McClements, D. J.; Decker, E. A. (2007). "Role of Physical Structures in Bulk Oils on Lipid Oxidation". Critical Reviews in Food Science and Nutrition 47 (3): 299–317. doi:10.1080/10408390600754248. PMID 17453926.
- Evangelos C. Rizos, MD, PhD; Evangelia E. Ntzani, MD, PhD; Eftychia Bika, MD; Michael S. Kostapanos, MD; Moses S. Elisaf, MD, PhD, FASA, FRSH (September 2012). "Association Between Omega-3 Fatty Acid Supplementation and Risk of Major Cardiovascular Disease Events A Systematic Review and Meta-analysis". JAMA 308 (10): 1024–1033. doi:10.1001/2012.jama.11374. PMID 22968891.
- Sala-Vila, A; Calder, PC (2011 Oct-Nov). "Update on the relationship of fish intake with prostate, breast, and colorectal cancers.". Critical reviews in food science and nutrition 51 (9): 855–71. doi:10.1080/10408398.2010.483527. PMID 21888535.
- MacLean, CH; Newberry, SJ; Mojica, WA; Khanna, P; Issa, AM; Suttorp, MJ; Lim, YW; Traina, SB; Hilton, L; Garland, R; Morton, SC (2006-01-25). "Effects of omega-3 fatty acids on cancer risk: a systematic review.". JAMA: the Journal of the American Medical Association 295 (4): 403–15. doi:10.1001/jama.295.4.403. PMID 16434631.
- MacLean, Catherine H. et al. (2006). "Effects of n-3 Fatty Acids on Cancer Risk". JAMA 295 (4): 403–415. doi:10.1001/jama.295.4.403. PMID 16434631. Retrieved 2006-07-07.
- Lee Hooper et al. (2006). "Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review". BMJ 332 (7544): 752–760. doi:10.1136/bmj.38755.366331.2F. PMC 1420708. PMID 16565093. Retrieved 2006-07-07.
- "Omega-3 Fatty Acids and Health".
- Colomer R, Moreno-Nogueira JM, García-Luna PP et al. (May 2007). "N-3 fatty acids, cancer and cachexia: a systematic review of the literature". Br. J. Nutr. 97 (5): 823–31. doi:10.1017/S000711450765795X. PMID 17408522.
- Zheng, J.-S.; Hu, X.-J.; Zhao, Y.-M.; Yang, J.; Li, D. (27 June 2013). "Intake of fish and marine n-3 polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies". BMJ 346 (jun27 5): f3706–f3706. doi:10.1136/bmj.f3706.
- Heinze, VM; Actis, AB (2012 Feb). "Dietary conjugated linoleic acid and long-chain n-3 fatty acids in mammary and prostate cancer protection: a review.". International journal of food sciences and nutrition 63 (1): 66–78. PMID 21762028.
- Chua, Michael E.; Sio, Maria Christina D.; Sorongon, Mishell C.; Morales, Marcelino L. Jr. (May–June 2013). "The relevance of serum levels of long chain omega-3 polyunsaturated fatty acids and prostate cancer risk: a meta-analysis". Canadian Urological Association Journal 7 (5–6): E333–E343. doi:10.5489/cuaj.1056. PMC 3668400. PMID 23766835.
- Kwak, SM; Myung, SK; Lee, YJ; Seo, HG; for the Korean Meta-analysis Study, Group (2012-04-09). "Efficacy of Omega-3 Fatty Acid Supplements (Eicosapentaenoic Acid and Docosahexaenoic Acid) in the Secondary Prevention of Cardiovascular Disease: A Meta-analysis of Randomized, Double-blind, Placebo-Controlled Trials". Archives of Internal Medicine 172 (9): 686–94. doi:10.1001/archinternmed.2012.262. PMID 22493407.
- Kotwal, Sradha; David Sullivan, Vlado Perkovic, Bruce Neal (18). "Omega 3 Fatty Acids and Cardiovascular Outcomes: Systematic Review and Meta-Analysis". Circ Cardiovasc Qual Outcomes 5 (6): 808–18. doi:10.1161/CIRCOUTCOMES.112.966168. PMID 23110790.
- Delgado-Lista, J; Perez-Martinez, P; Lopez-Miranda, J; Perez-Jimenez, F (2012 Jun). "Long chain omega-3 fatty acids and cardiovascular disease: a systematic review". The British journal of nutrition. 107 Suppl 2: S201–13. doi:10.1017/S0007114512001596. PMID 22591894.
- Pharmacy & Therapeutics (May, 2008) "Omega-3-acid Ethyl Esters (Lovaza) For Severe Hypertriglyceridemia"
- Appel LF, Miller ER, Sidler AJ, Whelton PK (1993). "Does supplementation of diet with 'fish oil' reduce blood pressure? A meta-analysis of controlled clinical trials". Archives of Internal Medicine 153 (12): 1429–1438. doi:10.1001/archinte.153.12.1429. PMID 8141868.
- von Schacky C. (March 2003). "The role of omega-3 fatty acids in cardiovascular disease". Curr. Atheroscler. Rep. 5 (2): 139–45. doi:10.1007/s11883-003-0086-y. PMID 12573200.
- Morris, Martha C.; Sacks, Frank; Rosner, Bernard (1993). "Does fish oil lower blood pressure? A meta-analysis of controlled trials". Circulation 88 (2): 523–533. doi:10.1161/01.CIR.88.2.523. PMID 8339414.
- Mori, Trevor A.; Bao, Danny Q.; Burke, Valerie; Puddey, Ian B.; Beilin, Lawrence J. (1993). "Docosahexaenoic acid but not eicosapentaenoic acid lowers ambulatory blood pressure and heart rate in humans". Hypertension 34 (2): 253–260. doi:10.1161/01.HYP.34.2.253. PMID 10454450.
- Harris, William S. (1997). "n-3 fatty acids and serum lipoproteins: human studies". Am J Clin Nutr 65 (5 Sup.): 1645S–1654S. PMID 9129504.
- Sanders, T.A.B.; Oakley, F.R.; Miller, G.J.; Mitropoulos, K.A.; Crook, D.; Oliver, M.F. (1997). "Influence of n-6 versus n-3 polyunsaturated fatty acids in diets low in saturated fatty acids on plasma lipoproteins and hemostatic factors". Arteriosclerosis, Thrombosis, and Vascular Biology 17 (12): 3449–3460. doi:10.1161/01.ATV.17.12.3449. PMID 9437192.
- Davidson MH, Stein EA, Bays HE, Maki KC, Doyle RT, Shalwitz RA, Ballantyne CM, Ginsberg HN (C2007). "Efficacy and tolerability of adding prescription omega-3 fatty acids 4 g/d to Simvastatin 40 mg/d in hypertriglyceridemic patients: An 8-week, randomized, double-blind, placebo-controlled study". Clin Ther. 29 (7): 1354–1367. doi:10.1016/j.clinthera.2007.07.018. PMID 17825687.
- Bucher HC, Hengstler P, Schindler C, Meier G. (March 2002). "n-3 polyunsaturated fatty acids in coronary heart disease: a meta-analysis of randomized controlled trials". Am J Med 112 (4): 298–304. doi:10.1016/S0002-9343(01)01114-7. PMID 11893369.
- Wang, C; Harris, WS; Chung, M; Lichtenstein, AH; Balk, EM; Kupelnick, B; Jordan, HS; Lau, J (2006 Jul). "n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review". The American journal of clinical nutrition 84 (1): 5–17. PMID 16825676.
- Iso, H.; Rexrode, K.M.; Stampfer, M.J.; Manson, J.E.; Colditz, G.A.; Speizer, F.E.; Hennekens, C.H.; Willett, W.C. (2001). "Intake of fish and omega-3 fatty acids and risk of stroke in women". JAMA 285 (3): 304–312. doi:10.1001/jama.285.3.304. PMID 11176840.
- Su, Kuan-Pin; Huang, Shih-Yi; Chiub, Chih-Chiang; Shenc, Winston W. (2003). "Omega-3 fatty acids in major depressive disorder: A preliminary double-blind, placebo-controlled trial". Eur Neuropsychopharmacol 13 (4): 267–271. doi:10.1016/S0924-977X(03)00032-4. PMID 12888186.
- Wall R, Ross RP, Fitzgerald GF, Stanton C (2010). "Fatty acids from fish: the anti-inflammatory potential of long-chain omega-3 fatty acids". Nutr Rev 68 (5): 280–9. doi:10.1111/j.1753-4887.2010.00287.x. PMID 20500789.
- Ruggiero C, Lattanzio F, Lauretani F, Gasperini B, Andres-Lacueva C, Cherubini A (2009). "Omega-3 polyunsaturated fatty acids and immune-mediated diseases: inflammatory bowel disease and rheumatoid arthritis". Curr Pharm Des 15 (36): 4135–48. doi:10.2174/138161209789909746. PMID 20041815.
- Fortin PR, Lew RA, Liang MH, Wright EA, Beckett LA, Chalmers TC, Sperling RI. (1995). "Validation of a meta-analysis: The effects of fish oil in rheumatoid arthritis". J Clin Epidemiol 48 (11): 1379–1390. doi:10.1016/0895-4356(95)00028-3. PMID 7490601.
- Levy, Susan E.; Hyman, Susan L. (2005). "Novel treatments for autistic spectrum disorders". Ment Retard Dev Disabil Res Rev 11 (2): 131–142. doi:10.1002/mrdd.20062. PMID 15977319.
- Richardson, Alexandra J. (2006). "Omega-3 fatty acids in ADHD and related neurodevelopmental disorders". Int Rev Psychiatry 18 (2): 155–172. doi:10.1080/09540260600583031. PMID 16777670.
- Richardson, Alexandra J.; Montgomery, Paul (2005). "The Oxford-Durham study: a randomized, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder". Pediatrics 115 (5): 1360–1366. doi:10.1542/peds.2004-2164. PMID 15867048.
- Bent, Stephen; Bertoglio, Kiah; Hendren, Robert L. (March 2009). "Omega-3 Fatty Acids for Autistic Spectrum Disorder: A Systematic Review". J Autism Dev Disord 39 (8): 1145–54. doi:10.1007/s10803-009-0724-5. PMC 2710498. PMID 19333748.
- Secher, NJ (2007). "Does fish oil prevent preterm birth?". Journal of perinatal medicine. 35 Suppl 1: S25–7. doi:10.1515/JPM.2007.033. PMID 17302537.
- Jensen, Craig L (2006). "Effects of n-3 fatty acids during pregnancy and lactation". Am J Clin Nutr 83 (6): 1452–1457. ISSN 0002-9165.
- Van De Rest, O.; Geleijnse, J. M.; Kok, F. J.; Van Staveren, W. A.; Dullemeijer, C.; Olderikkert, M.G.M.; Beekman, A. T.F.; De Groot, C. P.G.M. (August 2008). "Effects of Fish Oil on cognitive performance in older subjects". Neurology 71 (6): 430–38. doi:10.1212/01.wnl.0000324268.45138.86. PMID 18678826.
- Bain, S. (2010). "Achieving optimal omega-3 atty actid status in the vegan population". Beloit, WI: Biochemistry Program.
- Perica, MM; Delas, I (2011 Aug). "Essential fatty acids and psychiatric disorders". Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition 26 (4): 409–25. doi:10.1177/0884533611411306. PMID 21775637.
- Montgomery, P; Richardson, AJ (2008-04-16). "Omega-3 fatty acids for bipolar disorder". In Montgomery, Paul. Cochrane database of systematic reviews (Online) (2): CD005169. doi:10.1002/14651858.CD005169.pub2. PMID 18425912.
- Hegarty, B; Parker, G (2013 Jan). "Fish oil as a management component for mood disorders - an evolving signal". Current Opinion in Psychiatry 26 (1): 33–40. doi:10.1097/YCO.0b013e32835ab4a7. PMID 23108232.
- Sanhueza, C; Ryan, L; Foxcroft, DR (2012 Oct 18). "Diet and the risk of unipolar depression in adults: systematic review of cohort studies". Journal of human nutrition and dietetics : the official journal of the British Dietetic Association 26 (1): 56–70. doi:10.1111/j.1365-277X.2012.01283.x. PMID 23078460.
- Cederholm T, Palmblad J (March 2010). "Are omega-3 fatty acids options for prevention and treatment of cognitive decline and dementia?". Current Opinion in Clinical Nutrition and Metabolic Care 13 (2): 150–155. doi:10.1097/MCO.0b013e328335c40b. PMID 20019606.
- Mazereeuw G, Lanctôt KL, Chau SA, Swardfager W, Herrmann N (2012). "Effects of omega-3 fatty acids on cognitive performance: a meta-analysis". Neurobiol Aging 33 (7): e17–29. doi:10.1016/j.neurobiolaging.2011.12.014. PMID 22305186.
- Lewis, Christine J. "Letter Regarding Dietary Supplement Health Claim for Omega-3 Fatty Acids and Coronary Heart Disease". and "Letter Regarding Dietary Supplement Health Claim for Omega-3 Fatty Acids and Coronary Heart Disease". U.S. Food and Drug Administration via Internet Archive. October 31, 2000. Archived from the original on 2006-12-17. Retrieved 2009-10-30.
- Lands, William E.M. (1992). "Biochemistry and physiology of n–3 fatty acids". FASEB Journal (Federation of American Societies for Experimental Biology) 6 (8): 2530–2536. PMID 1592205. Retrieved 2008-03-21.
- Bergstrom, Danielson, Klenberg, and Samuelsson (Nov 1964). "The Enzymatic Conversion of Essential fatty Acids into Prostaglandins". The Journal of Biological Chemistry 239 (11): PC4006–PC4008.
- Bain, S. (2010). "Achieving optimal omega-3 fatty acid status in the vegan population". Beloit, WI: Biochemistry Program.
- Gerster H (1998). "Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)?". Int. J. Vitam. Nutr. Res. 68 (3): 159–173. PMID 9637947.
- Brenna JT (March 2002). "Efficiency of conversion of alpha-linolenic acid to long chain n-3 fatty acids in man". Current Opinion in Clinical Nutrition and Metabolic Care 5 (2): 127–132. doi:10.1097/00075197-200203000-00002. PMID 11844977.
- Burdge GC, Calder PC (September 2005). "Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults". Reprod. Nutr. Dev. 45 (5): 581–597. doi:10.1051/rnd:2005047. PMID 16188209.
- Oregon State University Micronutrient Information Center: Essential Fatty Acids-Metabolism and Bioavailability http://lpi.oregonstate.edu/infocenter/othernuts/omega3fa/#metabolism
- "Conversion Efficiency of ALA to DHA in Humans". Retrieved 21 October 2007.
- Goyens, Petra LL et al. (1 July 2006). "Conversion of alpha-linolenic acid in humans is influenced by the absolute amounts of alpha-linolenic acid and linoleic acid in the diet and not by their ratio". American Journal of Clinical Nutrition 84 (1): 44–53. PMID 16825680. Retrieved 21 October 2007.
- Okuyama H (2001). "High n-6 to n-3 ratio of dietary fatty acids rather than serum cholesterol as a major risk factor for coronary heart disease". Eur J Lipid Sci Technol 103 (6): 418–422. doi:10.1002/1438-9312(200106)103:6<418::AID-EJLT418>3.0.CO;2-#.
- Griffin BA (2008). "How relevant is the ratio of dietary omega-6 to omega-3 polyunsaturated fatty acids to cardiovascular disease risk? Evidence from the OPTILIP study". Current Opinion in Lipidology 19 (1): 57–62. doi:10.1097/MOL.0b013e3282f2e2a8. PMID 18196988.
- Mozaffarian D, Ascherio A, Hu FB, Stampfer MJ, Willett WC, Siscovick DS, Rimm EB., D; Ascherio, A; Hu, FB; Stampfer, MJ; Willett, WC; Siscovick, DS; Rimm, EB (2005). "Interplay Between Different Polyunsaturated Fatty Acids and Risk of Coronary Heart Disease in Men". Circulation 111 (2): 157–64. doi:10.1161/01.CIR.0000152099.87287.83. PMC 1201401. PMID 15630029.
- Willett WC, WC (2007). "The role of dietary n-6 fatty acids in the prevention of cardiovascular disease". J Cardiovasc Med 8: Suppl 1:S42–5. doi:10.2459/01.JCM.0000289275.72556.13. PMID 17876199.
- Tribole, E.F.; Thompson, RL; Harrison, RA; Summerbell, CD; Ness, AR; Moore, HJ; Worthington, HV; Durrington, PN et al. (2006). "Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review". BMJ 332 (7544): 752–760. doi:10.1136/bmj.38755.366331.2F. PMC 1420708. PMID 16565093. Retrieved 2008-03-23.
- S.K. Duckett et al; Neel, J. P. S.; Fontenot, J. P.; Clapham, W. M. (2009,). "Effects of winter stocker growth rate and finishing system on: III. Tissue proximate, fatty acid, vitamin and cholesterol content". Journal of Animal Science 87 (9): 2961–70. doi:10.2527/jas.2009-1850. PMID 19502506.
- Lands, WEM (2005). Fish, Omega 3 and human health. American Oil Chemists' Society. ISBN 978-1-893997-81-3.
- Simopoulos, Artemis P. (October 2002). "The importance of the ratio of omega-6/omega-3 essential fatty acids". Biomedicine & Pharmacotherapy 56 (8): 365–379. doi:10.1016/S0753-3322(02)00253-6. PMID 12442909. also see the abstract of this article online
- Daley, C. A.; Abbott, A.; Doyle, P.; Nader, G.; and Larson, S. (2004). A literature review of the value-added nutrients found in grass-fed beef products. California State University, Chico (College of Agriculture). Retrieved 2008-03-23.
- Simopoulos, AP (September 2003). "Importance of the ratio of omega-6/omega-3 essential fatty acids: evolutionary aspects". World Review of Nutrition and Dietetics. World Review of Nutrition and Dietetics 92: 1–174. doi:10.1159/000073788. ISBN 3-8055-7640-4. PMID 14579680.
- Simopoulos AP, Leaf A, Salem Jr N (2000). "Workshop Statement on the essentiality of and recommended dietary intakes for n-6 and n-3 fatty acids". Prostaglandins Leukot Essent Fatty Acids 63 (3): 119–121. doi:10.1054/plef.2000.0176. PMID 10991764.
- Hibbeln, J. R.; Nieminen, L. R.; Blasbalg, T. L.; Riggs, J. A.; Lands, W. E. (2006). "Healthy intakes of n-3 and n-6 fatty acids: Estimations considering worldwide diversity". The American journal of clinical nutrition 83 (6 Suppl): 1483S–1493S. PMID 16841858.
- Martina Bavec; Franc Bavec (2006). Organic Production and Use of Alternative Crops. London: Taylor & Francis Ltd. p. 178. ISBN 1-4200-1742-X. Retrieved 2013-02-18.
- Erasmus, Udo, Fats and Oils. 1986. Alive books, Vancouver, ISBN 0-920470-16-5 p. 263 (round-number ratio within ranges given.)
- "Essential Fats in Food Oils". National Institutes of Health. Retrieved 2012-03-06.
- Dusheck J (October 1985). "Fish, Fatty Acids, and Physiology". Science News. 128 (16): 241–256.
- Holman RT (February 1998). "The slow discovery of the importance of omega 3 essential fatty acids in human health". J. Nutr. 128 (2 Suppl): 427S–433S. PMID 9478042.
- "FDA announces qualified health claims for omega-3 fatty acids" (Press release). United States Food and Drug Administration. September 8, 2004. Retrieved 2006-07-10.
- Canadian Food Inspection Agency. Summary Table of Biological Role Claims Table 8-2. http://www.inspection.gc.ca/english/fssa/labeti/guide/ch8e.shtml
- "Fish, Levels of Mercury and Omega-3 Fatty Acids". American Heart Association. Retrieved October 6, 2010.
- Kris-Etherton, Penny M.; William S. Harris, Lawrence J. Appel (2002). "Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease". Circulation 106 (21): 2747–2757. doi:10.1161/01.CIR.0000038493.65177.94. PMID 12438303.
- "Omega-3 Centre". Omega-3 sources. Omega-3 Centre. Archived from the original on 2008-07-18. Retrieved 2008-07-27.
- Food and Nutrition Board (2005). Dietary Reference Intakes For Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, D.C.: Institute of Medicine of the National Academies. pp. 423; 770. ISBN 0-309-08537-3.
- "Product Review: Omega-3 Fatty Acids (EPA and DHA) from Fish/Marine Oils". ConsumerLab.com. 2005-03-15. Retrieved 2007-08-14.
- Bent S, Bertoglio K, Hendren RL (August 2009). "Omega-3 fatty acids for autistic spectrum disorder: a systematic review". J Autism Dev Disord 39 (8): 1145–54. doi:10.1007/s10803-009-0724-5. PMC 2710498. PMID 19333748.
- International Fish Oils Standard
- Kris-Etherton, PM, Harris, WS, Appel LJ (2002). "Fish consumption, fish oil, omega-3 acids and cardiovascular disease". Circulation 106 (21): 2747–2757. doi:10.1161/01.CIR.0000038493.65177.94. PMID 12438303.
- Falk-Petersen, S., S. et al. (1998). "Lipids and fatty acids in ice algae and phytoplankton from the Marginal Ice Zone in the Barents Sea". Polar Biology 20 (1): 41–47. doi:10.1007/s003000050274. ISSN 0722-4060.
- Innis, SM; Rioux, FM; Auestad, N; Ackman, RG (1995 Sep). "Marine and freshwater fish oil varying in arachidonic, eicosapentaenoic and docosahexaenoic acids differ in their effects on organ lipids and fatty acids in growing rats.". The Journal of nutrition 125 (9): 2286–93. PMID 7666244.
- Lawson, L.D.; Hughes, B.G. (1988). "Absorption of eicosapentaenoic acid and docosahexaenoic acid from fish oil triacylglycerols or fish oil ethyl esters co-ingested with a high-fat meal". Biochem. Biophys. Res. Commun. 156 (2): 960–963. doi:10.1016/S0006-291X(88)80937-9. PMID 2847723.
- Beckermann, B.; Beneke, M.; Seitz, I. (1990). "Comparative bioavailability of eicosapentaenoic acid and docasahexaenoic acid from triglycerides, free fatty acids and ethyl esters in volunteers". Arzneimittel-Forschung (in German) 40 (6): 700–704. PMID 2144420.
- Ulven SM; Kirkhus, B; Lamglait, A; Basu, S; Elind, E; Haider, T; Berge, K; Vik, H et al. (January 2011). "Metabolic Effects of Krill Oil are Essentially Similar to Those of Fish Oil but at Lower Dose of EPA and DHA, in Healthy Volunteers". Lipids 46 (1): 37–46. doi:10.1007/s11745-010-3490-4. PMC 3024511. PMID 21042875.
- "Seed Oil Fatty Acids - SOFA Database Retrieval". In German. Google translation
- DeFilippis, Andrew P.; Laurence S. Sperling. "Understanding omega-3's" (PDF). Archived from the original on 22 October 2007.
- Wilkinson, Jennifer. "Nut Grower's Guide: The Complete Handbook for Producers and Hobbyists" (PDF). Retrieved 21 October 2007.
- Thomas Bartram (September 2002). Bartram's Encyclopedia of Herbal Medicine: The Definitive Guide to the Herbal Treatments of Diseases. Da Capo Press. p. 271. ISBN 978-1-56924-550-7.
- Decsi, T.; Kennedy, K. (2011). "Sex-specific differences in essential fatty acid metabolism". American Journal of Clinical Nutrition 94 (6_Suppl): 1914S–1919S. doi:10.3945/ajcn.110.000893. PMID 22089435.
- Simopoulos, A. P.; Norman, H. A.; Gillaspy, J. E.; Duke, J. A.; (August 1992). "Common purslane: a source of omega-3 fatty acids and antioxidants". J Am Coll Nutr 11 (4): 374–382. PMID 1354675.
- "How Omega-6s Usurped Omega-3s In US Diet".
- Trebunová, A.; Vasko, L.; Svedová, M.; Kasteľ, R.; Tucková, M.; Mach, P. (July 2007). "The influence of omega-3 polyunsaturated fatty acids feeding on composition of fatty acids in fatty tissues and eggs of laying hens". Deutsche Tierärztliche Wochenschrift 114 (7): 275–279. PMID 17724936.
- Cherian, G. Effect of feeding full fat flax and canola seeds to laying hens on the fatty acids composition of eggs, embryos, and newly hatched chicks. http://agris.fao.org/agris-search/search/display.do?f=1991%2FUS%2FUS91146.xml%3BUS9138554
- Sterling, Colin (2010-06-03). "Washington Post's Egg Taste Test Says Homegrown And Factory Eggs Taste The Same [UPDATED, POLL]". Huffingtonpost.com. Retrieved 2011-01-03.
- Garton, G. A. (1960). "Fatty Acid Composition of the Lipids of Pasture Grasses". Nature 187 (4736): 511. doi:10.1038/187511b0.
- Duckett, S. K., D. G. Wagner, et al. (1993). "Effects of time on feed on beef nutrient composition". J Anim Sci 71 (8): 2079–2088. PMID 8376232.
- "Specially Labeled Lamb".
- Azcona, J.O., Schang, M.J., Garcia, P.T., Gallinger, C., R. Ayerza (h), and Coates, W. (2008). "Omega-3 enriched broiler meat: The influence of dietary alpha-linolenic omega-3 fatty acid sources on growth, performance and meat fatty acid composition". Canadian Journal of Animal Science 88 (2): 257–269. doi:10.4141/CJAS07081.
- "Gourment Game - Amazing Nutrition Facts".
- "DHA in Brain and Retina Structure".
- "Nutrition for the Brain".
- "Natural Health Product Monograph - Seal Oil". Health Canada. June 22, 2009. Retrieved June 20, 2012.
- European Parliament (9 November 2009). "MEPs adopt strict conditions for the placing on the market of seal products in the European Union". Hearings. European Parliament. Retrieved 12 March 2010.
- Vincent JT van Ginneken, Johannes PFG Helsper, Willem de Visser, Herman van Keulen and Willem A Brandenburg (2011). "Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas". Lipids in Health and Disease 10 (104): 104. doi:10.1186/1476-511X-10-104. PMC 3131239. PMID 21696609.
- Couvreur, S.; Hurtaud, C.; Lopez, C.; Delaby, L.; Peyraud, J.-L. (June 2006). "The Linear Relationship Between the Proportion of Fresh Grass in the Cow Diet, Milk Fatty Acid Composition, and Butter Properties". Journal of Dairy Science 89 (6): 1956–69. doi:10.3168/jds.S0022-0302(06)72263-9. PMID 16702259. Retrieved 16 March 2013.
- Allport, Susan. The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them. University of California Press, September 2006. ISBN 978-0-520-24282-1.
- Chow, Ching Kuang. Fatty Acids in Foods and Their Health Implications. Routledge Publishing. New York. 2001.
- Clover, Charles. The End of the Line: How overfishing is changing the world and what we eat. Ebury Press, London 2004. ISBN 0-09-189780-7
- Stoll, Andrew L. The Omega-3 Connection. Simon & Schuster 2001. ISBN 0-684-87138-6.
- University of Maryland Medical Center, omega-3 Fatty Acids
- MedlinePlus Herbs and Supplements: Omega-3 fatty acids, fish oil, alpha-linolenic acid