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Encyclopedia > Essential fatty acid
Types of Fats in Food
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Essential fatty acids, or EFAs, are fatty acids that cannot be constructed within an organism from other components (generally all references are to humans) by any known chemical pathways; and therefore must be obtained from the diet. The term refers to those involved in biological processes, and not fatty acids which may just play a role as fuel. As many of the compounds created from essential fatty acids can be taken directly in the diet, it is possible that the amounts required in the diet (if any) are overestimated. It is also possible they can be underestimated as organisms can still survive in unideal, malnourished conditions. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. ... For discussion how dietary fats affect cardiovascular health, see Diet and heart disease. ... // In nutrition, polyunsaturated fat is an abbreviation of polyunsaturated fatty acid. ... A trans fatty acid (commonly shortened to trans fat) is an unsaturated fatty acid molecule that contains a trans double bond between carbon atoms, which makes the molecule less kinked compared to cis fat. Research suggests a correlation between diets high in trans fats and diseases like atherosclerosis and coronary... It has been suggested that Fish oil, Oily fish be merged into this article or section. ... Omega-6 fatty acids are fatty acids where the term omega-6 signifies that the first double bond in the carbon backbone of the fatty acid, counting from the end opposite the acid group, occurs in the sixth carbon-carbon bond. ... Omega-9 fatty acids are a class of unsaturated fatty acids which have a C=C double bond in the ω-9 position. ... Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. ... Interesterified fats are oils (such as soybean oil) that have been chemically modified. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Image File history File links Portal. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ...


There are two families of EFAs: ω-3 (or omega-3 or n-3) and ω-6 (omega-6, n-6.) Fats from each of these families are essential, as the body can convert one omega-3 to another omega-3, for example, but cannot create an omega-3 from scratch. They were originally designated as Vitamin F when they were discovered as essential nutrients in 1923. In 1930, work by Burr, Burr and Miller showed that they are better classified with the fats than with the vitamins.[1] It has been suggested that Fish oil, Oily fish be merged into this article or section. ... Omega-6 fatty acids are fatty acids where the term omega-6 signifies that the first double bond in the carbon backbone of the fatty acid, counting from the end opposite the acid group, occurs in the sixth carbon-carbon bond. ... Year 1923 (MCMXXIII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ... Year 1930 (MCMXXX) was a common year starting on Wednesday (link will display 1930 calendar) of the Gregorian calendar. ... Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... Retinol (Vitamin A) For the record label, see Vitamin Records A vitamin is an organic compound required in tiny amounts for essential metabolic reactions in a living organism. ...

Contents

Functions

The biological effects of the ω-3 and ω-6 fatty acids are largely mediated by their mutual interactions, see Essential fatty acid interactions for detail.

In the body, essential fatty acids serve multiple functions. In each of these, the balance between dietary ω-3 and ω-6 strongly affects function The actions of the ω-3 and ω-6 essential fatty acids (EFAs) are best characterized by their interactions; they cannot be understood separately. ...

  • They are modified to make
  • They form lipid rafts (affecting cellular signaling)[2]
  • They act on DNA (activating or inhibiting transcription factors such as NFκB, which is linked to pro-inflammatory cytokine production ) [3]

Nomenclature and terminology

Fatty acids are straight chain hydrocarbons possessing a carboxyl (COOH) group at one end. The carbon next to the carboxylate is known as α, the next carbon β, and so forth. Since biological fatty acids can be of different lengths, the last position is labelled ω, the last letter in the Greek alphabet. Since the physiological properties of unsaturated fatty acids largely depend on the position of the first unsaturation relative to the end position and not the carboxylate, the position is signified by (ω minus n). For example, the term ω-3 signifies that the first double bond exists as the third carbon-carbon bond from the terminal CH3 end (ω) of the carbon chain. The number of carbons and the number of double bonds is also listed. ω-3 18:4 (stearidonic acid) or 18:4 ω-3 or 18:4 n-3 indicates an 18-carbon chain with 4 double bonds, and with the first double bond in the third position from the CH3 end. Double bonds are cis and separated by a single methylene (CH2) group unless otherwise noted. So in free fatty acid form, the chemical structure of stearidonic acid is: In biochemistry, eicosanoids are a class of oxygenated hydrophobic molecules that largely function as autocrine and paracrine mediators. ... Cannabinoids are a group of chemicals which activate the bodys cannabinoid receptors. ... ... Resolvins are compounds that are made by the human body from eicosapentaenoic acid (EPA). ... Isofurans are eicosanoid compounds formed nonenzymatically by free radical mediated peroxidation of arachidonic acid. ... The isoprostanes are prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation of arachidonic acid independent of the cyclooxygenase enzyme. ... Chemical structure of 14,15-epoxyeicosatrienoic acid. ... A lipid raft is a cholesterol-enriched microdomain in cell membranes. ... NFkB is a transcription factor important in mediating proinflammatory host immune responses. ... Cytokines are a group of proteins and peptides that are used in organisms as signaling compounds. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted... The Greek alphabet is an alphabet that has been used to write the Greek language since about the 9th century BCE. It was the first alphabet in the narrow sense, that is, a writing system using a separate symbol for each vowel and consonant alike. ... Omega-3 fatty acids are polyunsaturated fatty acids found in certain fish tissues, and in vegetable sources such as flax seeds, walnuts, and canola oil. ... Stearidonic acid is an ω-3 essential fatty acid, sometimes called moroctic acid. ... Cis-2-butene Trans-2-butene In chemistry, geometric isomerism or cis-trans isomerism is a form of stereoisomerism and describes the orientation of functional groups within the molecule. ...

Chemical structure of stearidonic acid showing physiological (red) and chemical (blue) numbering conventions.

Image File history File links Download high resolution version (1236x169, 5 KB) Summary Chemical structure of stearidonic acid showing numbering conventions, created with ChemDraw. ... Image File history File links Download high resolution version (1236x169, 5 KB) Summary Chemical structure of stearidonic acid showing numbering conventions, created with ChemDraw. ...

Examples

For a complete tables of ω-3 and ω-6 essential fatty acids, see Polyunsaturated fatty acids.

The essential fatty acids start with the short chain polyunsaturated fatty acids (SC-PUFA): A polyunsaturated fatty acid (PUFA) is a class of unsaturated fat that contains more than one double bond. ...

These two fatty acids cannot be synthesised by humans, as humans lack the desaturase enzymes required for their production. They form the starting point for the creation of longer and more desaturated fatty acids, which are also referred to as long-chain polyunsaturated fatty acids (LC-PUFA): Linolenic acid Alpha-linolenic acid (ALA) is a polyunsaturated omega-3 fatty acid with the molecular formula C18H30O2 and molar mass 278. ... The chemical strucuture of linoleic acid showing physiological numbering (red) and chemical numbering (blue) conventions. ... Biosynthesis is a phenomenon where chemical compounds are produced from simpler reagents. ... A Desaturase is an enzyme which removes two hydrogen atoms from an organic compound, creating a carbon/carbon double bond. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ...

ω-9 fatty acids are not essential in humans, because humans possess all the enzymes required for their synthesis. The public is sometimes perceived as ignorant of this, as many supplement companies market Omega 3-6-9 blends. It has been suggested that Fish oil, Oily fish be merged into this article or section. ... Eicosapentaenoic acid (EPA or also icosapentaenoic acid) is an omega-3 fatty acid. ... Docosahexaenoic acid (commonly known as DHA; 22:6(ω-3), all-cis-docosa-4,7,10,13,16,19-hexaenoic acid; trivial name cervonic acid) is an omega-3 essential fatty acid. ... Omega-6 fatty acids are fatty acids where the term omega-6 signifies that the first double bond in the carbon backbone of the fatty acid, counting from the end opposite the acid group, occurs in the sixth carbon-carbon bond. ... gamma-Linolenic acid (GLA) is an omega-6 essential fatty acid found primarily in vegetable oils. ... Dihomo-gamma-linolenic acid (DGLA) is 20-carbon ω-3 fatty acid. ... Arachidonic acid (AA) is an omega-6 fatty acid 20:4(ω-6). ... Omega-9 fatty acids are a class of unsaturated fatty acids which have a C=C double bond in the ω-9 position. ...


What is "essential"?

Between 1930 and 1950, arachidonic acid and linolenic acid were termed 'essential' because each was more or less able to meet the growth requirements of rats given fat-free diets. Further research has shown that human metabolism requires both ω-3 and ω-6 fatty acids. To some extent, any ω-3 and any ω-6 can relieve the worst symptoms of fatty acid deficiency. Particular fatty acids are still needed at critical life stages (e.g. lactation) and in some disease states. See (Cunnane 2003)[4] for a discussion of the current status of the term 'essential'. In scientific writing, common usage is that the term essential fatty acid comprises all the ω-3 or -6 fatty acids.[5] Authorative sources include the whole families, without qualification.[6] [7] [8] The human body can make some long-chain PUFA (arachidonic acid, EPA and DHA) from lineolate or lineolinate. Arachidonic acid (AA) is an omega-6 fatty acid 20:4(ω-6). ... Linolenic acid Alpha-linolenic acid (ALA) is a polyunsaturated omega-3 fatty acid with the molecular formula C18H30O2 and molar mass 278. ...


Some writers therefore hold that the LC-PUFA are not essential, but that is not how the field has generally used the term.


Biologist Ray Peat, PhD, has pointed out flaws in the studies purportedly showing the need for n-3 and n-6 fats. He notes that so-called EFA deficiencies have been reversed by adding B vitamins or a fat-free liver extract to the diet. In his view, 'the optional dietary level of the "essential fatty acids" might be close to zero, if other dietary factors were also optimized.' [1]


Essential fatty acids should not be confused with essential oils, which are "essential" in the sense of being a concentrated essence. An essential oil is a concentrated, hydrophobic liquid containing volatile aromatic compounds from plants. ...

Food sources

Almost all the polyunsaturated fat in the human diet is from EFA. Some of the food sources of ω-3 and ω-6 fatty acids are fish and shellfish, flaxseed (linseed), hemp oil, soya oil, canola (rapeseed) oil, chia seeds, pumpkin seeds, sunflower seeds, leafy vegetables, and walnuts. A giant grouper at the Georgia Aquarium Fish are aquatic vertebrates that are cold-blooded, covered with scales, and equipped with two sets of paired fins and several unpaired fins. ... Cooked mussels Shellfish is a term used to describe shelled molluscs and crustaceans used as food. ... Binomial name Linum usitatissimum Linnaeus. ... This article does not cite its references or sources. ... Binomial name (L.) Merr. ... For the figure in Celtic mythology see agriculture, canola are certain varieties of plants from which we get rapeseed oil, or the oil produced from those varieties. ... Binomial name Salvia hispanica L. Chia (Salvia hispanica) is a plant of the genus Salvia of the mint family. ... Pumpkin seeds are occasionally served as a snack during autumn holidays like Halloween or Thanksgiving. ... The sunflower seed is the seed of the sunflower (Helianthus annuus). ... Chinese cabbage Swiss chard Leaf vegetables, also called greens or leafy greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. ... “Walnut Tree” redirects here. ...


Essential fatty acids play a part in many metabolic processes, and there is evidence to suggest that low levels of essential fatty acids, or the wrong balance of types among the essential fatty acids, may be a factor in a number of illnesses. A few of the metabolic pathways in a cell. ...


Plant sources of ω-3 do not contain eicosapentaenoic acid and docosahexaenoic acid. This is thought to be the reason that absorption of essential fatty acids is much greater from animal rather than plant sources (see Fish and plants as a source of Omega-3 for more). Eicosapentaenoic acid (EPA or also icosapentaenoic acid) is an omega-3 fatty acid. ... Docosahexaenoic acid (commonly known as DHA; 22:6(ω-3), all-cis-docosa-4,7,10,13,16,19-hexaenoic acid; trivial name cervonic acid) is an omega-3 essential fatty acid. ... Oily fish (oil-rich fish, pelagic fish) are those fish which have oils throughout the fillet and in the belly cavity around the gut, rather than only in the liver like white fish. ...


The IUPAC Lipid HandbookPDF (370 KiB) provides a very large and detailed listing of fat contents of animal and vegetable fats, including ω-3 and -6 oils. The National Institutes of Health's EFA Education group publishes 'Essential Fats in Food Oils.' This lists 40 common oils, more tightly focused on EFAs and sorted by n-6:3 ratio. Stuchlik and Zak, 'Vegetable Lipids as Components of Functional Food'PDF (139 KiB) list notable vegetable sources of EFAs as well as commentary and an overview of the biosynthetic pathways involved. Users can interactively search at Nutrition Data for the richest food sources of particular EFAs or other nutrients. Careful readers will note that these sources are not in excellent agreement. EFA content of vegetable sources varies with cultivation conditions. Animal sources vary widely, both with the animal's feed and that the EFA makeup varies markedly with fats from different body parts. The Portable Document Format (PDF) is the file format created by Adobe Systems, in 1993, for document exchange. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... National Institutes of Health Building 50 at NIH Clinical Center - Building 10 The National Institutes of Health (NIH) is an agency of the United States Department of Health and Human Services and is the primary agency of the United States government responsible for biomedical research. ... The Portable Document Format (PDF) is the file format created by Adobe Systems, in 1993, for document exchange. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to...


Role in human health

For discussion how essential fatty acids affect cardiovascular health, see Diet and heart disease.

Almost all the polyunsaturated fats in the human diet are EFAs. Essential fatty acids play an important role in the life and death of cardiac cells.[9] [10] [11] [12] Diet may play an important role in causing or preventing heart disease. ... // In nutrition, polyunsaturated fat is an abbreviation of polyunsaturated fatty acid. ...


See also

// In nutrition, polyunsaturated fat is an abbreviation of polyunsaturated fatty acid. ... Omega-3 fatty acids are polyunsaturated fatty acids found in certain fish tissues, and in vegetable sources such as flax seeds, walnuts, and canola oil. ... Dietary sources of omega-6 fatty acids include: cereals whole-grain breads margarine most vegetable oils eggs and poultry baked goods. ... The actions of the ω-3 and ω-6 essential fatty acids (EFAs) are best characterized by their interactions; they cannot be understood separately. ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic molecules that largely function as autocrine and paracrine mediators. ... Chemical structure of prostaglandin E1 (PGE1). ... Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. ... Thromboxane is a member of the family of lipids known as eicosanoids. ... Cannabinoids are a group of chemicals which activate the bodys cannabinoid receptors. ... An essential nutrient is a nutrient required for normal body functioning that cannot be synthesized by the body. ... First, what is an amino acid? Amino Acids are chemical substances that make up protein. ... This article or section is in need of attention from an expert on the subject. ... Fatty acids are aliphatic acids fundamental to energy production and storage, cellular structure and as intermediates in the biosynthesis of hormones and other biologically important molecules. ... Oily fish (oil-rich fish, pelagic fish) are those fish which have oils throughout the fillet and in the belly cavity around the gut, rather than only in the liver like white fish. ...

References

  1. ^ Burr, G.O., Burr, M.M. and Miller, E. (1930). "On the nature and role of the fatty acids essential in nutrition". J. Biol. Chem. 86 (587). Retrieved on 2007-01-17. 
  2. ^ Stillwell W, Shaikh SR, Zerouga M, Siddiqui R, Wassall SR (2005). "Docosahexaenoic acid affects cell signaling by altering lipid rafts". REPRODUCTION, NUTRITION, DEVELOPMENT 45 (5): 559-579. PMID 16188208. 
  3. ^ Calder PC (2004). "n-3 fatty acids, inflammation, and immunity--relevance to postsurgical and critically ill patients". LIPIDS 39 (12): 1147-1161. PMID 15736910. 
  4. ^ Cunnane SC (2003). "Problems with essential fatty acids: time for a new paradigm?". PROGRESS IN LIPID RESEARCH 42 (6): 544-568. PMID 14559071. 
  5. ^ Or at least the polyunsaturated, straight-chain methylene-interrupted ones; conjugated fatty acids like calendic acid are not.
  6. ^ Heather Hutchins, MS, RD (10/19/2005). Symposium Highlights -- Omega-3 Fatty Acids: Recommendations for Therapeutics and Prevention.
    • "Omega-3 fatty acids and their counterparts, n-6 fatty acids, are essential polyunsaturated fatty acids (PUFA) because they cannot be synthesized de novo in the body."
  7. ^ Nugent K, Spigelman A, Phillips R (1996). "Tissue prostaglandin levels in familial adenomatous polyposis patients treated with sulindac". Dis Colon Rectum 39 (6): 659-62. PMID 8646953. 
    • "Arachidonic acid is an essential fatty acid..."
  8. ^ Carlstedt-Duke J, Brönnegård M, Strandvik B (1986). "Pathological regulation of arachidonic acid release in cystic fibrosis: the putative basic defect". Proc Natl Acad Sci U S A 83 (23): 9202-6. PMID 3097647. 
    • "[T]he turnover of essential fatty acids is increased (7). Arachidonic acid is one of the essential fatty acids affected."
  9. ^ "External blockade...by polyunsaturated fatty acids". PMID 43279. Retrieved on 2007-01-18.  - see page 1 of this link
  10. ^ "Antiarrythmic effects of omega-3 fatty acids". PMID 16919517. Retrieved on 2007-01-18. 
  11. ^ "Alpha-linolenic acid, cardiovascular disease and sudden death". PMID 17086218. Retrieved on 2007-01-18. 
  12. ^ "Omega-3 and health". PMID 17091903. Retrieved on 2007-01-18. 
  • A.E. Hansen et al (1963). "Role of linoleic acid in infant nutrition". Pediatrics 31:171

Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... January 17 is the 17th day of the year in the Gregorian calendar. ... A polyunsaturated fatty acid (PUFA) is a class of unsaturated fat that contains more than one double bond. ... Calendic acid (sometimes α-Calendic acid) is an unsaturated fatty acid, named for the pot marigold (genus Calendula), from which it is obtained. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 18th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 18th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 18th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 18th day of the year in the Gregorian calendar. ...

External links


  Results from FactBites:
 
Arachidonic acid - Wikipedia, the free encyclopedia (318 words)
Chemically, arachidonic acid is a carboxylic acid with a 20-carbon chain and four cis double bonds; the first double bond is located at the sixth carbon from the omega end.
Arachidonic acid is a polyunsaturated fatty acid that is present in the phospholipids (especially phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositides) of membranes of the body's cells, and is highly enriched in the brain.
Arachidonic acid is freed from phospholipid molecule by the enzyme phospholipase A2.
Essential fatty acid - Wikipedia, the free encyclopedia (831 words)
the lipoxins from ω-6 EFAs and resolvins from ω-3 (in the presence of aspirin, downregulating inflammation.)
Some of the food sources of ω-3 and ω-6 fatty acids are fish and shellfish, flaxseed (linseed), soya oil, canola (rapeseed) oil, hemp oil, chia seeds, pumpkin seeds, leafy vegetables, and walnuts.
Essential fatty acids play a part in many metabolic processes, and there is evidence to suggest that low levels of essential fatty acids, or the wrong balance of types among the essential fatty acids, may be a factor in a number of illnesses.
  More results at FactBites »

 
 

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