Essential fatty acids, or EFAs, are fatty acids In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. The most occurring natural fatty acids have an even number of carbon atoms because their biosynthesis involves acetyl-CoA, a coenzyme carrying a two-carbon-atom group (see fatty acid synthesis) that humans and other animals must ingest for good health because the body requires them but can't make them from other food components. The term refers to fatty acids required for biological processes, and not those that only act as fuel.
There are only two EFAs: alpha-linolenic acid α-Linolenic acid is an organic compound found in many common vegetable oils. Systematically, it is named all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is given the name 18:3, an omega-3 fatty acid n−3 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid, and linoleic acid Linoleic acid is an unsaturated omega-6 fatty acid. It is a colorless liquid at room temperature. In physiological literature, it is called 18:2(n-6). Chemically, linoleic acid is a carboxylic acid with an 18-carbon chain and two cis double bonds; the first double bond is located at the sixth carbon from the omega end, an omega-6 fatty acid n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the end opposite the carboxyl group. [1][2][3] Some researchers consider gamma-linolenic acid γ-Linolenic acid is a fatty acid found primarily in vegetable oils. It is sold as a dietary supplement for treating problems with inflammation and auto-immune diseases. The efficacy of such use is disputed (omega-6), lauric acid Lauric acid , a saturated fatty acid, is a white, powdery solid with a faint odor of bay oil or soap (saturated fatty acid), and palmitoleic acid Palmitoleic acid, or -9-hexadecenoic acid, is an omega-7 monounsaturated fatty acid with the formula CH3(CH2)5CH=CH(CH2)7COOH. that is a common constituent of the glycerides of human adipose tissue. It is present in all tissues, but generally found in higher concentrations in the liver. It is biosynthesized from palmitic acid by the action of the (monosaturated fatty acid) conditionally essential.[4]
They were originally designated as Vitamin F when they were discovered as essential nutrients in 1923. In 1930, work by Burr, Burr and Miller on rats showed that they are better classified with the fats Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure and composition. Although the words "oils", "fats", than with the vitamins A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and the particular organism. For.[5]
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Functions
- The biological effects of the ω-3 and ω-6 fatty acids are mediated by their mutual interactions, see Essential fatty acid interactions The actions of the ω-3 and ω-6(Omega-6) essential fatty acids (EFAs) are best characterized by their interactions; they cannot be understood separately 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.
- They are modified to make
- the classic eicosanoids In biochemistry, eicosanoids are signaling molecules made by oxidation of twenty-carbon essential fatty acids, . They exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system. The networks of controls that depend upon eicosanoids are among the most complex in the human body (affecting inflammation Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process. Inflammation is not a synonym for infection. Even in cases where inflammation is and many other cellular functions)
- the endocannabinoids Before the 1980s, it was often speculated that cannabinoids produced their physiological and behavioral effects via nonspecific interaction with cell membranes, instead of interacting with specific membrane-bound receptors. The discovery of the first cannabinoid receptors in the 1980s helped to resolve this debate. These receptors are common in (affecting mood, behavior and inflammation)
- the lipoxins Lipoxins are a series of anti-inflammatory mediators. Lipoxins are short lived endogenously produced nonclassic eicosanoids whose appearance in inflammation signals the resolution of inflammation. They are abbreviated as LX, an acronym for lipoxygenase interaction products. At present two lipoxins have been identified; lipoxin A4 (LXA4) and from ω-6 EFAs and resolvins Resolvins are compounds that are made by the human body from the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid (DHA). They are produced by the COX-2 pathway especially in the presence of aspirin. Experimental evidence indicates that resolvins reduce cellular inflammation by inhibiting the production and transportation of from ω-3 (in the presence of aspirin, downregulating inflammation.)
- the isofurans, neurofurans, isoprostanes, hepoxilins, epoxyeicosatrienoic acids (EETs) and Neuroprotectin D Neuroprotectin D1 is a docosanoid derived from the polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA), which is a component of fish oil and the most important omega-3 PUFA. NPD1 exerts potent anti-inflammatory and anti-apoptotic bioactivity at nanomolar concentrations in a variety of experimental models of brain and retinal diseases
- They form lipid rafts (affecting cellular signaling)[6]
- They act on DNA (activating or inhibiting transcription factors such as NFκB, which is linked to pro-inflammatory cytokine Cytokines are any of a number of small proteins that are secreted by specific cells of the immune system and glial cells, which carry signals locally between cells, and thus have an effect on other cells. They are a category of signaling molecules that are used extensively in cellular communication. They are proteins, peptides, or glycoproteins production)[7]
Nomenclature and terminology
Fatty acids are straight chain hydrocarbons possessing a carboxyl Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. A carboxyl group is a functional group consisting of a carbonyl and a hydroxyl, which has the formula -C(=O)OH, usually written -COOH or -CO2H. Carboxylic acids are Brønsted-Lowry acids — they are proton donors. Salts and anions of carboxylic acids (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 as a "ω", the last letter in the Greek alphabet The Greek alphabet is a set of twenty-four letters that has been used to write the Greek language since the late 9th or early 8th century BC. It is the first and oldest alphabet in the narrow sense that it notes each vowel and consonant with a separate symbol. It is as such in continuous use to this day. The letters were also used to represent. 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 n−3 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid 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 Stearidonic acid is an ω-3 essential fatty acid, sometimes called moroctic acid. It is biosynthesized from alpha-linolenic acid by the enzyme delta-6-desaturase. Natural sources of this fatty acid are the seed oils of hemp, blackcurrant and echium, and the cyanobacterium spirulina) 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 In organic chemistry, cis-trans isomerism or geometric isomerism or configuration isomerism or E-Z isomerism is a form of stereoisomerism describing the orientation of functional groups within a molecule. In general, such isomers contain double bonds, which cannot rotate, but they can also arise from ring structures, wherein the rotation of bonds and separated by a single methylene (CH2) group unless otherwise noted. So in free fatty acid form, the chemical structure of stearidonic acid is:
Chemical structure of stearidonic acid showing physiological (red) and chemical (blue) numbering conventions.Examples
- For complete tables of ω-3 and ω-6 essential fatty acids, see Polyunsaturated fatty acids These fatty acids have 2 or more cis double bonds that are separated from each other by a single methylene group.
The essential fatty acids start with the short chain polyunsaturated fatty acids (SC-PUFA):
- ω-3 fatty acids n−3 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid:
- ω-6 fatty acids n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the end opposite the carboxyl group:
These two fatty acids cannot be synthesised Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step. Examples for such multi-step biosynthetic pathways are those for the by humans, as humans lack the desaturase A Desaturase is an enzyme that removes two hydrogen atoms from an organic compound, creating a carbon/carbon double bond. Desaturases are classified as enzymes Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their 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):
- ω-3 fatty acids n−3 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid:
- eicosapentaenoic acid Eicosapentaenoic acid is an omega-3 fatty acid. In physiological literature, it is given the name 20:5(n-3). It also has the trivial name timnodonic acid. In chemical structure, EPA is a carboxylic acid with a 20-carbon chain and five cis double bonds; the first double bond is located at the third carbon from the omega end or EPA (20:5)
- docosahexaenoic acid Docosahexaenoic acid is an omega-3 fatty acid. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end. Its trivial name is cervonic acid, its systematic name is all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid, and its shorthand name is 2 or DHA (22:6)
- ω-6 fatty acids n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the end opposite the carboxyl group:
- gamma-linolenic acid γ-Linolenic acid is a fatty acid found primarily in vegetable oils. It is sold as a dietary supplement for treating problems with inflammation and auto-immune diseases. The efficacy of such use is disputed or GLA (18:3)
- dihomo-gamma-linolenic acid Dihomo-γ-linolenic acid is a 20-carbon ω−6 fatty acid. In physiological literature, it is given the name 20:3 (ω−6). Chemically, DGLA is a carboxylic acid with a 20-carbon chain and three cis double bonds; the first double bond is located at the sixth carbon from the omega end. DGLA is the elongation product of γ-linolenic acid (GLA; 18:3, or DGLA (20:3)
- arachidonic acid Arachidonic acid is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, (L. arachis – peanut.) or AA (20:4)
ω-9 fatty acids n−9 fatty acids are a family of unsaturated fatty acids which have in common a final carbon–carbon double bond in the n−9 position; that is, the ninth bond from the end of the fatty acid are not essential in humans, because humans generally possess all the enzymes required for their synthesis. Exceptions do occur in older people or people with a liver problem that do not completely produce a sufficient amount,[citation needed] and hence many supplement companies market Omega 3-6-9 blends.
Essentiality
Between 1930 and 1950, arachidonic acid Arachidonic acid is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, (L. arachis – peanut.) and linolenic acid α-Linolenic acid is an organic compound found in many common vegetable oils. Systematically, it is named all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is given the name 18:3 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. In nonscientific writing, common usage is that the term essential fatty acid comprises all the ω-3 or -6 fatty acids Conjugated A conjugated system occurs in an organic compound where atoms covalently bond with alternating single and multiple bonds (e.g., C=C-C=C-C) and influence each other to produce a region called electron delocalization. In this region electrons do not belong to a single bond or atom, but rather a group. For example, phenol (C6H5OH, benzene with fatty acids like calendic acid are not normally considered essential. Authoritative sources include the whole families, without qualification.[8][9][10] The human body can make some long-chain PUFA (arachidonic acid, EPA and DHA) from lineolate or lineolinate.
Traditionally speaking the LC-PUFA are not essential. See (Cunnane 2003)[11] for a discussion of the current status of the term 'essential'. Because the LC-PUFA are sometimes required, they may be considered "conditionally essential", or not essential to healthy adults.
A 2005 study has shown evidence that gamma-linolenic acid, GLA γ-Linolenic acid is a fatty acid found primarily in vegetable oils. It is sold as a dietary supplement for treating problems with inflammation and auto-immune diseases. The efficacy of such use is disputed has been shown to inhibit the breast cancer promoting gene of Her2/neu HER2/neu stands for "Human Epidermal growth factor Receptor 2" and is a protein giving higher aggressiveness in breast cancers. It is a member of the ErbB protein family, more commonly known as the epidermal growth factor receptor family. HER2/neu has also been designated as CD340 (cluster of differentiation 340) and p185. It is encoded.[12]
Biologist Ray Peat has claimed there are flaws in the studies showing the need for n-3 and n-6 fats. He further claims that EFA deficiencies have sometimes 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.'[13] However, these views are contrary to the scientific consensus Scientific consensus is the collective judgement, position, and opinion of the community of scientists in a particular field of study. Consensus implies general agreement, though not necessarily unanimity. Scientific consensus is not by itself a scientific argument, and it is not part of the scientific method. Nevertheless, consensus may be based.
A deficiency of essential fatty acids results in scaly dermatitis, hair loss, and poor wound healing.[citation needed]
Essential fatty acids should not be confused with essential oils An essential oil is a concentrated, hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove. An oil is "essential" in the sense that it carries a, which are "essential" in the sense of being a concentrated essence.
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 A fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins. Most fish are "cold-blooded", or ectothermic, allowing their body temperatures to vary as ambient temperatures change. Fish are abundant in most bodies of water. They can be found in nearly all aquatic and shellfish Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater. In addition a few species of land crabs are eaten, for, flaxseed (linseed) Flax (binomial name: Linum usitatissimum) is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent. It is known as Agasi/Akshi in Kannada, जवस (Jawas/Javas) or अळशी (Alashi) in Marathi and तीसी, hemp oil Hempseed oil is pressed from the seed of the hemp plant irrespective of the strain of cannabis. Cold pressed, unrefined hemp oil is dark to clear light green in color, with a pleasant nutty flavor. The darker the color, the grassier the flavour, soya oil, canola (rapeseed) oil, chia seeds, pumpkin seeds, sunflower 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, including osteoporosis.[14]
Plant sources of ω-3 contain neither eicosapentaenoic acid (EPA) nor docosahexaenoic acid (DHA). The human body can (and in case of a purely vegetarian diet often must, unless certain algae or supplements derived from them are consumed) convert α-linolenic acid (ALA) to EPA and subsequently DHA. This however requires more metabolic work, which is thought to be the reason that the 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).
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.
Human health
Main article: Diet and heart diseaseAlmost 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.[15][16][17][18]
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PR Newswire (press release) The calories are either released by the liver and circulate in VLDL or are metabolized by fat and released as fatty acids . Between meals, when the body ...
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Cyclooxygenases COXs can be divided into COX 1 present at constant levels in most cells tissues and COX 2 normally absent from most cells but rapidly rising to high levels in
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Fish oil is beneficial for the overall health of the person, because it provides the . essential. omega-3 . fatty acids. - EPA and DHA. There are a lot of . fatty. .
Q. Which is the nutritionally essential fatty acid? Why is it important?
Asked by ian - Thu Jan 1 05:16:53 2009 - - 1 Answers - 0 Comments
A. All the unsaturated fatty acids are important, but in the beginning of life of the babyes the most important in the arachidonic one, because reasons of metabolism.
Answered by Cacace - Thu Jan 1 11:31:06 2009
