Eicosapentaenoic acid
Encyclopedia
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.
EPA is a polyunsaturated fatty acid
(PUFA) that acts as a precursor for prostaglandin-3
(which inhibits platelet
aggregation), thromboxane
-3, and leukotriene
-5 groups (all eicosanoids).
or fish oil
— e.g., cod
liver, herring
, mackerel
, salmon
, menhaden
and sardine
. It is also found in human breast milk
.
However, fish do not naturally produce EPA, but obtain it from the algae
they consume. It is available to humans from some non-animal sources (e.g., commercially, from microalgae). Microalgae are being developed as a commercial source. EPA is not usually found in higher plants, but it has been reported in trace amounts in purslane. Microalgae, and supplements derived from it, are excellent alternative sources of EPA and other fatty acids, since fish often contain toxins due to pollution.
The human body can (and in case of a purely vegetarian diet often must, unless the aforementioned algae
or supplements derived from them are consumed) also convert alpha-linolenic acid
(ALA) to EPA, but this is much less efficient than the resorption of EPA from food containing it, and ALA is itself an essential fatty acid, an appropriate supply of which must be ensured. Because EPA is also a precursor
to docosahexaenoic acid
(DHA), ensuring a sufficient level of EPA on a diet containing neither EPA nor DHA is harder both because of the extra metabolic work required to synthesize EPA and because of the use of EPA to metabolize DHA. Medical conditions like diabetes
or certain allergies may significantly limit the human body's capacity for metabolization of EPA from ALA.
The US National Institute of Health's MedlinePlus lists medical conditions for which EPA (alone or in concert with other ω-3 sources) is known or thought to be an effective treatment. Most of these involve its ability to lower inflammation
.
Among omega-3 fatty acids, it is thought that EPA in particular may possess some beneficial potential in mental conditions, such as schizophrenia
.
Several studies report an additional reduction in scores on symptom scales used to assess the severity of symptoms, when additional EPA is taken.
Recent studies have suggested that EPA may decrease depression and, importantly, suicidal behavior. One such study, took blood samples of 100 suicide attempt patients and compared the blood samples to those of controls and found that levels of eicosapentaenoic acid were significantly lower in the washed red blood cells of the suicide-attempt patients.
EPA has inhibitory effect on CYP2C9
and CYP2C19
hepatic enzymes. At high dose, it may also inhibit the activity of CYP2D6
and CYP3A4
, important enzymes involved in drug metabolism.
Research suggests that EPA improves the response of patients to chemotherapy
, possibly by modulating the production of eicosanoid
.
Omega-3 fatty acid
N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain....
. In physiological literature, it is given the name 20:5(n-3). It also has the trivial name
Trivial name
In chemistry, a trivial name is a common name or vernacular name; it is a non-systematic name or non-scientific name. That is, the name is not recognised according to the rules of any formal system of nomenclature...
timnodonic acid. In chemical structure, EPA is a carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
with a 20-carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
chain and five cis double bonds; the first double bond is located at the third carbon from the omega end.
- EPA and its metabolites act in the body largely by their interactions with the metabolites of arachidonic acidArachidonic acidArachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...
; see Essential fatty acid interactionsEssential fatty acid interactionsThe actions of the ω-3 and ω-6 essential fatty acids are best characterized by their interactions; they cannot be understood separately.Arachidonic acid is a 20-carbon ω-6 conditionally essential fatty acid...
for detail.
EPA is a polyunsaturated fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
(PUFA) that acts as a precursor for prostaglandin-3
Prostaglandin
A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....
(which inhibits platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
aggregation), thromboxane
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....
-3, and leukotriene
Leukotriene
Leukotrienes are fatty signaling molecules. They were first found in leukocytes . One of their roles is to trigger contractions in the smooth muscles lining the trachea; their overproduction is a major cause of inflammation in asthma and allergic rhinitis...
-5 groups (all eicosanoids).
Sources
It is obtained in the human diet by eating oily fishOily fish
Oily fish have oil in their tissues and in the belly cavity around the gut. Their fillets contain up to 30 percent oil, although this figure varies both within and between species...
or fish oil
Fish oil
Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid , and docosahexaenoic acid , precursors of certain eicosanoids that are known to reduce inflammation throughout the body, and are thought to have many health benefits.Fish do not...
— e.g., cod
Cod
Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...
liver, herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
, mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
, salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
, menhaden
Menhaden
Menhaden, also known as mossbunker, bunker and pogy, are forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the family Clupeidae.-Description:...
and sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
. It is also found in human breast milk
Breast milk
Breast milk, more specifically human milk, is the milk produced by the breasts of a human female for her infant offspring...
.
However, fish do not naturally produce EPA, but obtain it from the algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
they consume. It is available to humans from some non-animal sources (e.g., commercially, from microalgae). Microalgae are being developed as a commercial source. EPA is not usually found in higher plants, but it has been reported in trace amounts in purslane. Microalgae, and supplements derived from it, are excellent alternative sources of EPA and other fatty acids, since fish often contain toxins due to pollution.
The human body can (and in case of a purely vegetarian diet often must, unless the aforementioned algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
or supplements derived from them are consumed) also convert alpha-linolenic acid
Alpha-linolenic acid
α-Linolenic acid is an organic compound found in many common vegetable oils. In terms of its structure, it is named all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is given the name 18:3 ....
(ALA) to EPA, but this is much less efficient than the resorption of EPA from food containing it, and ALA is itself an essential fatty acid, an appropriate supply of which must be ensured. Because EPA is also a precursor
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....
to docosahexaenoic acid
Docosahexaenoic acid
Docosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain and retina. 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...
(DHA), ensuring a sufficient level of EPA on a diet containing neither EPA nor DHA is harder both because of the extra metabolic work required to synthesize EPA and because of the use of EPA to metabolize DHA. Medical conditions like diabetes
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
or certain allergies may significantly limit the human body's capacity for metabolization of EPA from ALA.
Clinical significance
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...
.
Among omega-3 fatty acids, it is thought that EPA in particular may possess some beneficial potential in mental conditions, such as schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
.
Several studies report an additional reduction in scores on symptom scales used to assess the severity of symptoms, when additional EPA is taken.
Recent studies have suggested that EPA may decrease depression and, importantly, suicidal behavior. One such study, took blood samples of 100 suicide attempt patients and compared the blood samples to those of controls and found that levels of eicosapentaenoic acid were significantly lower in the washed red blood cells of the suicide-attempt patients.
EPA has inhibitory effect on CYP2C9
CYP2C9
Cytochrome P450 2C9 is a protein that in humans is encoded by the CYP2C9 gene.- Function :CYP2C9 is an important cytochrome P450 enzyme with a major role in the oxidation of both xenobiotic and endogenous compounds. CYP2C9 makes up about 18% of the cytochrome P450 protein in liver microsomes...
and CYP2C19
CYP2C19
Cytochrome P450 2C19 , a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. It is involved in the metabolism of several...
hepatic enzymes. At high dose, it may also inhibit the activity of CYP2D6
CYP2D6
Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Also, many substances are bioactivated by CYP2D6 to form their active compounds...
and CYP3A4
CYP3A4
Cytochrome P450 3A4 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. CYP3A4 is involved in the oxidation of the largest range of substrates of all the CYPs. As a result, CYP3A4 is present in...
, important enzymes involved in drug metabolism.
Research suggests that EPA improves the response of patients to chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
, possibly by modulating the production of eicosanoid
Eicosanoid
In biochemistry, eicosanoids are signaling molecules made by oxidation of twenty-carbon essential fatty acids, ....
.
See also
- ChlorellaChlorellaChlorella is a genus of single-celled green algae, belonging to the phylum Chlorophyta. It is spherical in shape, about 2 to 10 μm in diameter, and is without flagella. Chlorella contains the green photosynthetic pigments chlorophyll-a and -b in its chloroplast...
- Cyanobacteria
- Docosahexaenoic acidDocosahexaenoic acidDocosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain and retina. 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...
(DHA) - List of omega-3 fatty acids
- Polyunsaturated fatty acidPolyunsaturated fatty acidPolyunsaturated fatty acids are fatty acids that contain more than one double bond in their backbone. This class includes many important compounds, such as essential fatty acids and those that give drying oils their characteristic property....
s - WakameWakame, Undaria pinnatifida, or Miyeok in Korean, is a sea vegetable, or edible seaweed. It has a subtly sweet flavour and is most often served in soups and salads....