fatty acids(redirected from essential fatty acids EFA)
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fatty acidsA large group of monobasic acids found in animals and plants. They are hydrocarbon chains and are saturated or unsaturated aliphatic compounds with an even number of carbon atoms. Chain lengths range up to nearly 30 carbon atoms. Fatty acids with more than about 8 carbon atoms in the chain occur most commonly as constituents of glycerides, phospholipids and sterols. The most abundant fatty acids are palmitic, stearic and oleic acids. Glucose and fatty acids are the two main fuel substances of the body. FATS are glyceride esters of fatty acids.
fatty acidsa range of molecules with the general formula Cn H2n+ 1COOH that occur naturally in many organisms, often combined with glycerol to form FATS. Fatty acids are of two main types: unsaturated, with at least one carbon-to-carbon double bond, and saturated, with no such bonds. The greater the proportion of unsaturated fatty acids in a fat the lower its melting point, with many unsaturated fats being liquid oils at room temperature. There is evidence that excess consumption of saturated fats can lead to hardening of the arteries (see ARTERIOSCLEROSIS), but the facts are disputed, particularly by butter manufacturers.
fatty acidsthe main components of fat, consisting of straight hydrocarbon chains with the number of carbon atoms ranging from 4 to more than 20, although chains of 16 and 18 are the most prevalent. All fat-containing foods, and all fat or lipid in the human body, consist of a mixture of different proportions of (1) saturated fatty acids (SFA) which have only single bonds between carbon atoms, all the remaining bonds being attached to hydrogen. SFA occur primarily in animal products like beef, lamb, pork, chicken, cream, milk, butter. Coconut and palm oil, hydrogenated margarine, commercially prepared cakes, pies, and biscuits are also rich in SFA; (2) monounsaturated fatty acids (MUFA) which have one double bond along the main carbon chain. They are present in canola oil, olive oil, peanut oil and oil in almonds, pecans and avocados; (3) polyunsaturated fatty acids (PUFA) which have two or more double bonds along the main carbon chain. Safflower, sunflower, soybean and corn oil are rich in PUFA. See also essential fatty acids, free fatty acids, omega-3 fatty acids.
pertaining to or characterized by fat. See also adipose.
organic compounds of carbon, hydrogen and oxygen that are esterified with glycerol to form fat. All fats are esters of fatty acids and glycerol, the fatty acids accounting for 90% of the molecule of most natural fats. A fatty acid consists of a long chain of carbon atoms with a carboxylic acid group at one end. Saturated fatty acids have no double bonds in the carbon chain. The medium and long chain fatty acids are solid at room temperature and are the components of the common animal fats, such as butter and lard. Unsaturated fatty acids contain one or more double bonds. The unsaturated fatty acids are liquid at room temperature and are found in oils such as olive oil and linseed oil. Polyunsaturated fatty acids have two or more double bonds.
Volatile fatty acids (VFAs) including acetic, butyric and propionic acids are produced in large quantities in the rumen by the fermentative digestion of cellulose. Much of the energy consumption of ruminants comes from these VFAs in the situation in which other animals use glucose. See also 3-omega fatty acid (below).
fatty acid nutritional deficiency
a secondary deficiency occurs in pigs on high-calcium diets. This may have a connection with parakeratosis of pigs caused by zinc deficiency and calcium excess in the diet. Requirements for dietary fat in dogs and cats are usually expressed as the essential linoleic acid and arachidonic acid.
fatty acid synthase
in bacteria, a multiprotein complex; in mammals, a single multifunctional protein important in the synthesis of palmitate as a major source of fatty acids.
fatty acyl CoA
generic term for long hydrocarbon chains, generally between C12 and C20, linked via thioester to coenzyme A.
fatty acyl CoA:cholesterol acyltransferase
enzyme (ACAT) catalyzing the transfer of fatty acyl group to cholesterol, irreversible physiologically. Its action regulates the number of LDL receptors by converting excess cholesterol (which inhibits LDL receptors) to cholesterol esters.
branched chain fatty acids
fatty acids usually containing a methyl branch; lowers the melting point compared with the equivalent straight chain fatty acid.
see urinary cast.
deposit of fat globules in a tissue.
essential fatty acids (EFA)
essential fatty acids.
accumulation of fat in a liver beyond the level which is normally encountered may be a result of a normal physiological response to increased peripheral lipolysis, obesity or the action of hepatotoxins.
fatty liver disease
see fat cow syndrome.
fatty liver syndrome
1. a disease of laying birds housed in battery cages. The cause is unknown. Affected birds are significantly heavier, there is a fall in egg production and they die acutely of liver rupture. The liver is greasy, mushy in consistency and yellow in color.
2. a severe fatty accumulation in the liver and hypertriglyceridemia that may develop in obese cats that are anorexic. There is jaundice, weight loss, neurological signs and a high mortality. Called also idiopathic feline hepatic lipidosis.
omega-3 (n-3) fatty acids
include α-linolenic acid, eicosapentanoic acid, docosahexanoic acid. High concentrations found in cold water marine (fish) oils.
omega-6 (n-6) fatty acids
found in terrestrial plants, including safflower oil, corn oil and evening primrose oil, which is a rich source of linoleic and arachidonic acids.
connective tissue made of fat cells in a meshwork of areolar tissue.