Omega-9 fatty acids (ω−9 fatty acids or ''n''−9 fatty acids) are a family of
unsaturated fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...
s which have in common a final carbon–carbon
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 ...
in the
omega−9 position; that is, the ninth bond from the
methyl
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...
end of the fatty acid.
Unlike
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 ...
s and
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 ...
, omega−9 fatty acids are not classed as
essential fatty acids
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 ...
(EFA). This is both because they can be created by the human body from
unsaturated fat
An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
...
, and are therefore not essential in the diet, and because the lack of an omega−6 double bond keeps them from participating in the reactions that form the
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.
Background
Some omega−9 fatty acids are common components of
animal fat
Animal fats and oils are lipids derived from animals: oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides. Although many animal parts and secretions may yield oil, in commercial p ...
and
vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fat ...
.
Two omega−9 fatty acids important in industry are:
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Oleic acid
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omega ...
(18:1, ''n''−9), which is a main component of
olive oil
Olive oil is a liquid fat obtained from olives (the fruit of ''Olea europaea''; family Oleaceae), a traditional tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is commonly used in cooking: f ...
,
macadamia oil
Macadamia oil (or macadamia nut oil) is the non-volatile oil collected from the nuts of the macadamia (''Macadamia integrifolia''), a native Australian plant. It is used in food as a frying or salad oil, and in cosmetic formulations as an emollien ...
and other
monounsaturated fat
Monounsaturated fats are fatty acids that have one double bond in the fatty acid chain with all of the remainder carbon atoms being single-bonded. By contrast, polyunsaturated fats have more than one double bond.
Molecular description
Fatty aci ...
s
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Erucic acid
Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1ω9. It has the chemical formula CH3(CH2)7CH=CH(CH2)11COOH. It is prevalent in wallflower seed and other plants in the family Brassicaceae, with a reported content of 20 to 54% i ...
(22:1, ''n''−9), which is found in
rapeseed
Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains a ...
,
wallflower
''Erysimum'', or wallflower, is a genus of flowering plants in the cabbage family, Brassicaceae. It includes more than 150 species, both popular garden plants and many wild forms. The genus ''Cheiranthus'' is sometimes included here in whole o ...
seed, and
mustard seed
Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about in diameter and may be colored from yellowish white to black. They are an important spice in many regional foods and may come from one of three diff ...
. Rapeseed with high erucic acid content is grown for commercial use in paintings and coatings as a
drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (not ...
.
Canola oil
Close-up of canola blooms
Canola flower
Rapeseed oil is one of the oldest known vegetable oils. There are both edible and industrial forms produced from rapeseed, the seed of several cultivars of the plant family Brassicaceae. Historically, i ...
comes from a
cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...
of the rapeseed plant that has been bred, or in some cases genetically modified, to contain very little erucic acid.
Under severe conditions of EFA deprivation, mammals will elongate and desaturate oleic acid to make
Mead acid
Mead acid is an omega-9 fatty acid, first characterized by James F. Mead. As with some other omega-9 polyunsaturated fatty acids, animals can make Mead acid ''de novo''. Its elevated presence in the blood is an indication of essential fatty acid ...
, (20:3, ''n''−9).
This has been documented to a lesser extent in one study following
vegetarians
Vegetarianism is the practice of abstaining from the consumption of meat (red meat, poultry, seafood, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slaughter.
Vegetarianism ma ...
and
semi-vegetarians who followed diets without substantial sources of EFA.
See also
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Polyunsaturated fatty acid
Polyunsaturated fatty acids (PUFAs) 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 proper ...
, lists of fatty acids including omega−3, omega−6, and omega−9 fatty acids
*
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 ...
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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 ...
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Omega-7 fatty acid
Omega-7 fatty acids are a class of unsaturated fatty acids in which the site of unsaturation is seven carbon atoms from the end of the carbon chain. The two most common omega-7 fatty acids in nature are palmitoleic acid and vaccenic acid. They ...
References
External links
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{{DEFAULTSORT:Omega-9 Fatty Acid
Fatty acids
Alkenoic acids
de:Omega-n-Fettsäuren#Omega-9-Fettsäuren