Arachidonic acid (AA, sometimes ARA) is a

polyunsaturated In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple e ...

omega-6 fatty acid Omega-6 fatty acids (also referred to as ω-6 fatty acids or ''n''-6 fatty acids) are a family of polyunsaturated fatty acids that have in common a final carbon-carbon double bond in the ''n''-6 position, that is, the sixth bond, counting from ...

20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated

arachidic acid Arachidic acid, also known as icosanoic acid, is a saturated fatty acid with a 20-carbon chain. It is a minor constituent of cupuaçu butter (7%), perilla oil (0–1%), peanut oil (1.1–1.7%), corn oil (3%),U.S. Department of Agriculture, Agricul ...

found in cupuaçu butter. Its name derives from the

New Latin New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy ...

word ''arachis'' (peanut), but

peanut oil Peanut oil, also known as groundnut oil or arachis oil, is a vegetable oil derived from peanuts. The oil usually has a mild or neutral flavor but, if made with roasted peanuts, has a stronger peanut flavor and aroma. It is often used in American ...

does not contain any arachidonic acid.

Chemistry

chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of at ...

, arachidonic acid is a

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

with a 20-carbon chain and four ''

cis Cis or cis- may refer to: Places * Cis, Trentino, in Italy * In Poland: ** Cis, Świętokrzyskie Voivodeship, south-central ** Cis, Warmian-Masurian Voivodeship, north Math, science and biology * cis (mathematics) (cis(''θ'')), a trigonome ...

''-

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...

s; the first double bond is located at the sixth carbon from the omega end. Some chemistry sources define 'arachidonic acid' to designate any of the

eicosatetraenoic acid Eicosatetraenoic acid (ETA) designates any straight chain 20:4 fatty acid. Eicosatetraenoic acid belongs to the family of eicosanoids, molecules synthesized from oxidized polyunsaturated fatty acids (PUFAs) to mediate cell-cell communication. The ei ...

s. However, almost all writings in biology, medicine, and nutrition limit the term to ''all cis''-5,8,11,14-eicosatetraenoic acid.

Biology

Arachidonic acid is a polyunsaturated fatty acid present in the

phospholipid Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...

s (especially

phosphatidylethanolamine Phosphatidylethanolamine (PE) is a class of phospholipids found in biological membranes. They are synthesized by the addition of cytidine diphosphate-ethanolamine to diglycerides, releasing cytidine monophosphate. ''S''-Adenosyl methionine can s ...

phosphatidylcholine Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soyb ...

, and

phosphatidylinositide Phosphatidylinositol (or Inositol Phospholipid) consists of a family of lipids as illustrated on the right, where red is x, blue is y, and black is z, in the context of independent variation, a class of the phosphatidylglycerides. In such molecul ...

s) of

membranes A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...

of the body's

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

, and is abundant in the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

muscles Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...

, and

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

. Skeletal muscle is an especially active site of arachidonic acid retention, accounting for roughly 10-20% of the phospholipid fatty acid content typically. In addition to being involved in

cellular signaling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

as a lipid

second messenger Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form or cell signaling, encompassing both first me ...

involved in the regulation of signaling enzymes, such as PLC-γ, PLC-δ, and PKC-α, -β, and -γ isoforms, arachidonic acid is a key inflammatory intermediate and can also act as a

vasodilator Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...

. (Note separate synthetic pathways, as described in section below.)

Conditionally essential fatty acid

Arachidonic acid is not one of the

essential fatty acid Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. Only two fatty acids are known to be essential for humans: alpha-linolenic ac ...

s. However, it does become essential if a deficiency in

linoleic acid Linoleic acid (LA) is an organic compound with the formula COOH(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups are cis-trans isomerism, ''cis''. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 ''cis''-9,12. A linoleate is a salt (chem ...

exists or if an inability to convert linoleic acid to arachidonic acid occurs. Some mammals lack the ability or have a very limited capacity to convert linoleic acid to arachidonic acid, making it an essential part of their diets. Since linoleic acid consumption does not seem to affect levels of arachidonic acid in plasma/serum or erythrocytes, it is uncertain if humans can in fact convert linoleic acid to arachidonic acid. Since little or no arachidonic acid is found in common plants, such animals are obligate

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

s; the cat is a common example of having the inability to desaturate essential fatty acids. A commercial source of arachidonic acid has been derived, however, from the fungus ''

Mortierella alpina ''Mortierella'' species are soil fungi belonging to the order Mortierellales within the subphylum Mortierellomycotina (phylum: Mucoromycota). The widespread genus contains about 85 species. Taxonomy The genus name of ''Mortierella'' is in hon ...

''.

Biosynthesis and cascade in humans

Arachidonic acid is freed from

by hydrolysis, catalyzed by the

phospholipase A2 The enzyme phospholipase A2 (EC 3.1.1.4, PLA2, systematic name phosphatidylcholine 2-acylhydrolase) catalyse the cleavage of fatty acids in position 2 of phospholipids, hydrolyzing the bond between the second fatty acid “tail” and the glyce ...

(PLA₂). Arachidonic acid for signaling purposes appears to be derived by the action of group IVA cytosolic phospholipase A2 (cPLA₂, 85 kDa), whereas inflammatory arachidonic acid is generated by the action of a low-molecular-weight secretory PLA₂ (sPLA₂, 14-18 kDa). Arachidonic acid is a precursor to a wide range of

eicosanoid Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a sub-c ...

s: * The enzymes

cyclooxygenase Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as prosta ...

-1 and -2 (i.e. prostaglandin G/H synthase 1 and 2 ) convert arachidonic acid to

prostaglandin G2 Prostaglandin G2 is an organic peroxide belonging to the family of prostaglandins. The compound has been isolated as a solid, although it is usually used in vivo. It quickly converts into prostaglandin H2, a process catalyzed by the enzyme COX. ...

and

prostaglandin H2 Prostaglandin H2 is a type of prostaglandin and a precursor for many other biologically significant molecules. It is synthesized from arachidonic acid in a reaction catalyzed by a cyclooxygenase enzyme. The conversion from Arachidonic acid to P ...

, which in turn may be converted to various

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...

s, to

prostacyclin Prostacyclin (also called prostaglandin I2 or PGI2) is a prostaglandin member of the eicosanoid family of lipid molecules. It inhibits platelet activation and is also an effective vasodilator. When used as a drug, it is also known as epoprosteno ...

, to

thromboxane Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its ...

s, and to the 17-carbon product of thromboxane metabolism of prostaglandin G2/H2, 12-Hydroxyheptadecatrienoic acid (12-HHT). * The enzyme

5-lipoxygenase Arachidonate 5-lipoxygenase, also known as ALOX5, 5-lipoxygenase, 5-LOX, or 5-LO, is a non-heme iron-containing enzyme (EC 1.13.11.34) that in humans is encoded by the ''ALOX5'' gene. Arachidonate 5-lipoxygenase is a member of the lipoxygenase fa ...

catalyzes the oxidation of arachidonic acid to 5-hydroperoxyeicosatetraenoic acid ( 5-HPETE), which in turn converts to various

leukotriene Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase. Leukotrienes ...

s (i.e.,

leukotriene B4 Leukotriene B4 (LTB4) is a leukotriene involved in inflammation. It has been shown to promote insulin resistance in obese mice. Biochemistry Leukotriene B4 (LTB4) is a leukotriene involved in inflammation. It is produced from leukocytes in respo ...

leukotriene C4 Leukotriene C4 (LTC4) is a leukotriene. LTC4 has been extensively studied in the context of allergy and asthma. In cells of myeloid origin such as mast cells, its biosynthesis is orchestrated by translocation to the nuclear envelope along with c ...

leukotriene D4 Leukotriene D4 (LTD4) is one of the leukotrienes. Its main function in the body is to induce the contraction of smooth muscle, resulting in bronchoconstriction and vasoconstriction. It also increases vascular permeability. LTD4 is released by bas ...

, and

leukotriene E4 Leukotriene E4 (LTE4) is a cysteinyl leukotriene involved in inflammation. It is known to be produced by several types of white blood cells, including eosinophils, mast cells, tissue macrophages, and basophils, and recently was also found to be pr ...

as well as to 5-hydroxyeicosatetraenoic acid ( 5-HETE) which may then be further metabolized to 5-HETE's more potent 5-keto analog, 5-oxo-eicosatetraenoic acid (5-oxo-ETE) (also see 5-Hydroxyeicosatetraenoic acid. * The enzymes 15-lipoxygenase-1 (

ALOX15 ALOX15 (also termed arachidonate 15-lipoxygenase, 15-lipoxygenase-1, 15-LO-1, 15-LOX-1) is, like other lipoxygenases, a seminal enzyme in the metabolism of polyunsaturated fatty acids to a wide range of physiologically and pathologically importa ...

and 15-lipoxygenase-2 (

ALOX15B Arachidonate 15-lipoxygenase type II is an enzyme that in humans is encoded by the ''ALOX15B'' gene. ALOX15B, also known as 15-lipoxygenase-2 (15-LO-2 or 15-LOX-2), is distinguished from its related oxygenase, ALOX15 or 15-lipoxygenase-1. Fun ...

catalyzes the oxidation of arachidonic acid to 15-hydroperoxyeicosatetraenoic acid (15-HPETE), which may then be further converted to 15-hydroxyeicosatetraenoic acid (15-HETE) and

lipoxins A lipoxin (LX or Lx), an acronym for lipoxygenase interaction product, is a bioactive autacoid metabolite of arachidonic acid made by various cell types. They are categorized as nonclassic eicosanoids and members of the specialized pro-resolv ...

; 15-Lipoxygenase-1 may also further metabolize 15-HPETE to

eoxin Eoxins are proposed to be a family of proinflammatory eicosanoids (signaling compounds that regulate inflammatory and immune responses). They are produced by human eosinophils (a class of white blood cells), mast cells, the L1236 Reed–Sternberg c ...

s in a pathway analogous to (and presumably using the same enzymes as used in) the pathway which metabolizes 5-HPETE to leukotrienes. * The enzyme 12-lipoxygenase ( ALOX12) catalyzes oxidation of arachidonic acid to 12-hydroperoxyeicosatetraenoic acid (12-HPETE), which may then be metabolized to 12-hydroxyeicosatetraenoic acid (12-HETE) and to

hepoxilins Hepoxilins (Hx) are a set of epoxyalcohol metabolites of polyunsaturated fatty acids (PUFA), i.e. they possess both an epoxide and an alcohol (i.e. hydroxyl) residue. HxA3, HxB3, and their non-enzymatically formed isomers are nonclassic eicosanoi ...

. * Arachidonic acid is also a precursor to

anandamide Anandamide (ANA), also known as ''N''-arachidonoylethanolamine (AEA), is a fatty acid neurotransmitter. Anandamide was the first endocannabinoid to be discovered: it participates in the body's endocannabinoid system by binding to cannabinoid rec ...

. * Some arachidonic acid is converted into hydroxyeicosatetraenoic acids (HETEs) and

epoxyeicosatrienoic acid The epoxyeicosatrienoic acids or EETs are signaling molecules formed within various types of cells by the metabolism of arachidonic acid by a specific subset of Cytochrome P450 enzymes termed cytochrome P450 epoxygenases. These nonclassic eicosa ...

s (EETs) by

epoxygenase Epoxygenases are a set of membrane-bound, heme-containing cytochrome P450 (CYP P450 or just CYP) enzymes that metabolize polyunsaturated fatty acids to epoxide products that have a range of biological activities. The most thoroughly studied substr ...

. The production of these derivatives and their actions in the body are collectively known as the "arachidonic acid cascade"; see essential fatty acid interactions and the enzyme and metabolite linkages given in the previous paragraph for more details.

PLA₂ activation

PLA₂, in turn, is activated by ligand binding to receptors, including: *

5-HT2 receptor The 5-HT2 receptors are a subfamily of 5-HT receptors that bind the endogenous neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). The 5-HT2 subfamily consists of three G protein-coupled receptors (GPCRs) which are coupled to Gq/G11 and m ...

s *

mGLUR1 The glutamate receptor, metabotropic 1, also known as GRM1, is a human gene which encodes the metabotropic glutamate receptor 1 (mGluR1) protein. Function L-glutamate is the major excitatory neurotransmitter in the central nervous system and ...

bFGF Fibroblast growth factor 2, also known as basic fibroblast growth factor (bFGF) and FGF-β, is a growth factor and signaling protein encoded by the ''FGF2'' gene. It binds to and exerts effects via specific fibroblast growth factor receptor ''(FG ...

receptor * IFN-α receptor * IFN-γ receptor Furthermore, any agent increasing intracellular

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

may cause activation of some forms of PLA₂.

PLC activation

Alternatively, arachidonic acid may be cleaved from phospholipids after

phospholipase C Phospholipase C (PLC) is a class of membrane-associated enzymes that cleave phospholipids just before the phosphate group (see figure). It is most commonly taken to be synonymous with the human forms of this enzyme, which play an important role ...

(PLC) cleaves off the

inositol trisphosphate Inositol trisphosphate or inositol 1,4,5-trisphosphate abbreviated InsP3 or Ins3P or IP3 is an inositol phosphate signaling molecule. It is made by hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), a phospholipid that is located in the p ...

group, yielding

diacylglycerol A diglyceride, or diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. DAGs can act as sur ...

(DAG), which subsequently is cleaved by DAG lipase to yield arachidonic acid. Receptors that activate this pathway include: * A1 receptor *

D2 receptor Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the ''DRD2'' gene. After work from Paul Greengard's lab had suggested that dopamine receptors were the site of action of antipsychotic drugs, several groups, in ...

* α-2 adrenergic receptor * 5-HT1 receptor PLC may also be activated by

MAP kinase A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of protein kinase that is specific to the amino acids serine and threonine (i.e., a serine/threonine-specific protein kinase). MAPKs are involved in directing cellular responses ...

. Activators of this pathway include

PDGF Platelet-derived growth factor (PDGF) is one among numerous growth factors that regulate cell growth and division. In particular, PDGF plays a significant role in blood vessel formation, the growth of blood vessels from already-existing blood v ...

and FGF.

In the body

Muscle growth

Arachidonic acid promotes the repair and growth of skeletal muscle tissue via conversion to prostaglandin

PGF2alpha Prostaglandin F2α (PGF2α in prostanoid nomenclature), pharmaceutically termed carboprost is a naturally occurring prostaglandin used in medicine to induce labor and as an abortifacient. Prostaglandins are lipids throughout the entire body that ...

during and following

physical exercise Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic ...

. PGF2alpha promotes muscle protein synthesis by signaling through the

Akt Protein kinase B (PKB), also known as Akt, is the collective name of a set of three serine/threonine-specific protein kinases that play key roles in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transc ...

mTOR The mammalian target of sirolimus, rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding protein 12-rapamycin-associated protein 1 (FRAP1), is a kinase that in humans is encoded by the ''MT ...

pathway, similar to

leucine Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α- ca ...

β-hydroxy β-methylbutyric acid β-Hydroxy β-methylbutyric acid (HMB), otherwise known as its conjugate base, , is a naturally produced substance in humans that is used as a dietary supplement and as an ingredient in certain medical foods that are intended to promote wou ...

(HMB), and

phosphatidic acid Phosphatidic acids are anionic phospholipids important to cell signaling and direct activation of lipid-gated ion channels. Hydrolysis of phosphatidic acid gives rise to one molecule each of glycerol and phosphoric acid and two molecules of fatty ac ...

Brain

Arachidonic acid is one of the most abundant fatty acids in the brain, and is present in similar quantities to

docosahexaenoic acid Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, and retina. In physiological literature, it is given the name 22:6(n-3). It can be synthesized from alpha-lino ...

(DHA). The two account for about 20% of its fatty-acid content. Like DHA, neurological health is reliant upon sufficient levels of arachidonic acid. Among other things, arachidonic acid helps to maintain

hippocampal The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, an ...

cell membrane fluidity. It also helps protect the brain from oxidative stress by activating

peroxisome proliferator-activated receptor gamma Peroxisome proliferator- activated receptor gamma (PPAR-γ or PPARG), also known as the glitazone reverse insulin resistance receptor, or NR1C3 (nuclear receptor subfamily 1, group C, member 3) is a type II nuclear receptor functioning as a tran ...

. AA also activates

syntaxin Syntaxins are a family of membrane integrated Q-SNARE proteins participating in exocytosis. Domains Syntaxins possess a single C-terminal transmembrane domain, a SNARE domain (known as H3), and an N-terminal regulatory domain (Habc). Syntaxin ...

-3 (STX-3), a protein involved in the growth and repair of neurons. Arachidonic acid is also involved in early neurological development. In one study, infants (18 months) given supplemental arachidonic acid for 17 weeks demonstrated significant improvements in intelligence, as measured by the Mental Development Index. This effect is further enhanced by the simultaneous supplementation of AA with DHA. In adults, the disturbed metabolism of AA may contribute to neuropsychiatric disorders such as

Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...

and

bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...

. There is evidence of significant alterations in the conversion of arachidonic acid to other bioactive molecules (overexpression or disturbances in the AA enzyme cascade) in these conditions.

Alzheimer's disease

The biological roles of arachidonic acid and its metabolites have been explored in the context of various

neurodegenerative disorders A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...

, including Alzheimer's disease.

Dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...

ation of arachidonic acid during the early stages of Alzheimer's disease has been suggested, but the potential for benefit remains unclear.

Bodybuilding supplement

Arachidonic acid is marketed as an

anabolic Anabolism () is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-do ...

bodybuilding supplement Bodybuilding supplements are dietary supplements commonly used by those involved in bodybuilding, weightlifting, mixed martial arts, and Athletics (physical culture), athletics for the purpose of facilitating an increase in lean body mass. Bodybui ...

in a variety of products.

Dietary arachidonic acid and inflammation

Increased consumption of arachidonic acid will not cause inflammation during normal metabolic conditions unless

lipid peroxidation Lipid peroxidation is the chain of reactions of oxidative degradation of lipids. It is the process in which radical (chemistry), free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by ...

products are mixed in. Arachidonic acid is metabolized to both proinflammatory and anti-inflammatory eicosanoids during and after the inflammatory response, respectively. Arachidonic acid is also metabolized to inflammatory and anti-inflammatory eicosanoids during and after physical activity to promote growth. Chronic inflammation from exogenous toxins and excessive exercise should not be confused with acute inflammation from exercise and sufficient rest that is required by the inflammatory response to promote the repair and growth of the micro tears of tissues. However, the evidence is mixed. Some studies giving between 840 mg and 2,000 mg per day to healthy individuals for up to 50 days have shown no increases in inflammation or related metabolic activities.Changes in whole blood and clinical safety markers over 50 days of concomitant arachidonic acid supplementation and resistance training
. Wilborn, C, M Roberts, C Kerksick, M Iosia, L Taylor, B Campbell, T Harvey, R Wilson, M. Greenwood, D Willoughby and R Kreider. Proceedings of the International Society of Sports Nutrition (ISSN) Conference June 15–17, 2006. Others show that increased arachidonic acid levels are actually associated with reduced pro-inflammatory IL-6 and IL-1 levels and increased anti-inflammatory tumor necrosis factor-beta. This may result in a reduction in systemic inflammation. Arachidonic acid does still play a central role in inflammation related to injury and many diseased states. How it is metabolized in the body dictates its inflammatory or anti-inflammatory activity. Individuals with joint pains or active inflammatory disease may find that increased arachidonic acid consumption exacerbates symptoms, presumably because it is being more readily converted to inflammatory compounds. Likewise, high arachidonic acid consumption is not advised for individuals with a history of inflammatory disease, or who are in compromised health. Of note, while AA supplementation does not appear to have proinflammatory effects in healthy individuals, it may counter the anti-inflammatory effects of

omega-3 fatty acid Omega−3 fatty acids, also called Omega-3 oils, ω−3 fatty acids or ''n''−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond, three atoms away from the terminal methyl group in their chem ...

supplementation.

Health effects of arachidonic acid supplementation

Arachidonic acid supplementation in daily doses of 1,000–1,500 mg for 50 days has been well tolerated during several clinical studies, with no significant side effects reported. All common markers of health, including kidney and liver function, serum lipids, immunity, and platelet aggregation appear to be unaffected with this level and duration of use. Furthermore, higher concentrations of AA in muscle tissue may be correlated with improved insulin sensitivity. Arachidonic acid supplementation of the diets of healthy adults appears to offer no toxicity or significant safety risk. While studies looking at arachidonic acid supplementation in sedentary subjects have failed to find changes in resting inflammatory markers in doses up to 1,500 mg daily, strength-trained subjects may respond differently. One study reported a significant reduction in resting inflammation (via marker IL-6) in young men supplementing 1,000 mg/day of arachidonic acid for 50 days in combination with resistance training. This suggests that rather being pro-inflammatory, supplementation of AA while undergoing resistance training may actually improve the regulation of systemic inflammation. A meta-analysis looking for associations between heart disease risk and individual fatty acids reported a significantly reduced risk of heart disease with higher levels of EPA and DHA (omega-3 fats), as well as the omega-6 arachidonic acid. A scientific advisory from the American Heart Association has also favorably evaluated the health impact of dietary omega-6 fats, including arachidonic acid. The group does not recommend limiting this essential fatty acid. In fact, the paper recommends individuals follow a diet that consists of at least 5–10% of calories coming from omega-6 fats, including arachidonic acid. It suggests dietary AA is not a risk factor for heart disease, and may play a role in maintaining optimal metabolism and reduced heart disease risk. Maintaining sufficient intake levels of both omega-3 and omega-6 fatty acids, therefore, is recommended for optimal health. Arachidonic acid is not

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substan ...

ic, and studies show dietary level is not associated (positively or negatively) with risk of cancers. AA remains integral to the inflammatory and cell growth process, however, which is disturbed in many types of disease including cancer. Therefore, the safety of arachidonic acid supplementation in patients with cancer, inflammatory, or other diseased states is unknown, and supplementation is not recommended.

References

External links

Arachidonic Acid
at acnp.org * {{DEFAULTSORT:Arachidonic Acid Fatty acids Alkenoic acids Arachidonyl compounds

Chemistry

Biology

Conditionally essential fatty acid

Biosynthesis and cascade in humans

PLA2 activation

PLC activation

In the body

Muscle growth

Brain

Alzheimer's disease

Bodybuilding supplement

Dietary arachidonic acid and inflammation

Health effects of arachidonic acid supplementation

See also

References

External links

PLA₂ activation