FACTOID # 13: New York has America's lowest percentage of residents who are veterans.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Cholesterol" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Cholesterol
Cholesterol
IUPAC name (10R,13R)-10,13-dimethyl-17-(6-methylheptan-2-yl)-

2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H- cyclopenta[a]phenanthren-3-ol Image File history File links Cholesterol. ... Image File history File links Size of this preview: 800 × 562 pixelsFull resolution (1422 × 999 pixel, file size: 144 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ...

Identifiers
CAS number 57-88-5
PubChem 5997
SMILES CC(C)CCCC(C)C1CCC2C1 (CCC3C2CC=C4C3(CCC(C4)O)C)C
Properties
Molecular formula C27H46O
Molar mass 386.654
Appearance white crystalline powder [1]
Melting point

148-150 °C [1] CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... PubChem is a database of chemical molecules. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...

Boiling point

360 °C (decomposes) Italic text This article is about the boiling point of liquids. ...

Solubility in water 0.095 mg/l (30 °C)
Hazards
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Cholesterol is a sterol (a combination steroid and alcohol). Cholesterol is a lipid found in the cell membranes of all tissues, and it is transported in the blood plasma of all animals. Because cholesterol is synthesized by all eukaryotes, trace amounts of cholesterol are also found in membranes of plants and fungi. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... Sterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring. ... This article is about the chemical family of steroids. ... This article does not cite any references or sources. ... Some common lipids. ... Look up cell membrane in Wiktionary, the free dictionary. ... Blood plasma is the liquid component of blood, in which the blood cells are suspended. ... For other uses, see Animal (disambiguation). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... For other uses, see Plant (disambiguation). ... Subkingdom/Phyla Chytridiomycota Blastocladiomycota Neocallimastigomycota Glomeromycota Zygomycota Dikarya (inc. ...


The name originates from the Greek chole- (bile) and stereos (solid), and the chemical suffix -ol for an alcohol, as researchers first identified cholesterol in solid form in gallstones by François Poulletier de la Salle in 1769. However, it is only in 1815 that chemist Eugène Chevreul named the compound "cholesterine".[2] Bile (or gall) is a bitter, yellow or green alkaline fluid secreted by hepatocytes from the liver of most vertebrates. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... It has been suggested that Ending (linguistics) be merged into this article or section. ... This article does not cite any references or sources. ... 1769 was a common year starting on Sunday (see link for calendar). ... April 5-12: Mount Tambora explodes, changing climate. ... Michel Eugène Chevreul (August 31, 1786 – April 9, 1889) was an important French chemist whose work with fatty acids led to early applications in the fields of art and science. ...


Most of the cholesterol is synthesized by the body and some has dietary origin. Cholesterol is more abundant in tissues which either synthesize more or have more abundant densely-packed membranes, for example, the liver, spinal cord and brain. It plays a central role in many biochemical processes, such as the composition of cell membranes and the synthesis of steroid hormones. Cholesterol is insoluble in blood, but is transported in the circulatory system bound to one of the varieties of lipoprotein, spherical particles which have an exterior composed mainly of water-soluble proteins. The main types, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) carry cholesterol from and to the liver. For the bird, see Liver bird. ... The Spinal cord nested in the vertebral column. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... Biochemistry is the study of the chemical processes in living organisms. ... Look up cell membrane in Wiktionary, the free dictionary. ... Steroid hormones are steroids which act as hormones. ... A lipoprotein is a biochemical assembly that contains both proteins and lipids. ... Low-density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying somewhat in their size and contents, which carry cholesterol in the blood and around the body, for use by various cells. ... High density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size and contents, that carry cholesterol from the bodys tissues to the liver. ...


According to the lipid hypothesis, abnormally high cholesterol levels (hypercholesterolemia) and abnormal proportions of LDL and HDL are associated with cardiovascular disease by promoting atheroma development in arteries (atherosclerosis). This disease process leads to myocardial infarction (heart attack), stroke and peripheral vascular disease. As high LDL contributes to this process, it is termed "bad cholesterol", while high levels of HDL ("good cholesterol") offer a degree of protection. The balance can be redressed with exercise, a healthy diet, and sometimes medication. The lipid hypothesis was one of two hypotheses developed in the 1850s to explain the pathogenesis of atherosclerosis. ... Hypercholesterolemia (literally: high blood cholesterol) is the presence of high levels of cholesterol in the blood [1]. It is not a disease but a metabolic derangement that can be secondary to many diseases and can contribute to many forms of disease, most notably cardiovascular disease. ... Cardiovascular disease refers to the class of diseases that involve the heart or blood vessels (arteries and veins). ... In pathology, an atheroma (plural: atheromata) is an accumulation and swelling (-oma) in artery walls that is made up of cells, or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. ... Acute myocardial infarction (AMI or MI), more commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... For other uses, see Stroke (disambiguation). ... Peripheral vascular disease (PVD) is a disease in the large blood vessels of the arms, legs, and feet. ...

Contents

Physiology

Function

Cholesterol is required to build and maintain cell membranes; it regulates membrane fluidity over a wide range of temperatures. The hydroxyl group on cholesterol interacts with the phosphate head of the membrane, while the bulky steroid and the hydrocarbon chain is embedded in the membrane. Some research indicates that cholesterol may act as an antioxidant.[3] Cholesterol also aids in the manufacture of bile (which is stored in the gallbladder and helps digest fats), and is also important for the metabolism of fat soluble vitamins, including vitamins A, D, E and K. It is the major precursor for the synthesis of vitamin D and of the various steroid hormones (which include cortisol and aldosterone in the adrenal glands, and the sex hormones progesterone, the various estrogens, testosterone, and derivatives). Look up cell membrane in Wiktionary, the free dictionary. ... For other uses, see Temperature (disambiguation). ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... This article is about the chemical family of steroids. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... Space-filling model of the antioxidant metabolite glutathione. ... Bile (or gall) is a bitter, yellow or green alkaline fluid secreted by hepatocytes from the liver of most vertebrates. ... It has been suggested that this article or section be merged with Vitamin. ... Vitamin A is an essential human nutrient. ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Tocopherol, or Vitamin E, is a fat-soluble vitamin in eight forms that is an important antioxidant. ... Vitamin K1 (phylloquinone). ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Steroid hormones are steroids which act as hormones. ... Cortisol is a corticosteroid hormone produced by the adrenal cortex (in the adrenal gland). ... Aldosterone is a steroid hormone (mineralocorticoid family) produced by the outer-section (zona glomerulosa) of the adrenal cortex in the adrenal gland to regulate sodium and potassium balance in the blood. ... In mammals, the adrenal glands (also known as suprarenal glands) are the triangle-shaped endocrine glands that sit on top of the kidneys; their name indicates that position (ad-, near or at + -renes, kidneys). They are chiefly responsible for regulating the stress response through the synthesis of corticosteroids and catecholamines... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... Estriol. ... Testosterone is a steroid hormone from the androgen group. ...


Recently, cholesterol has also been implicated in cell signalling processes, where it has been suggested that it forms lipid rafts in the plasma membrane. It also reduces the permeability of the plasma membrane to hydrogen ions (protons) and sodium ions.[4] Lipid rafts are cholesterol-rich microdomains in cell membranes. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... For other uses, see Proton (disambiguation). ... General Name, symbol, number sodium, Na, 11 Chemical series alkali metals Group, period, block 1, 3, s Appearance silvery white Standard atomic weight 22. ...


Cholesterol is essential for the structure and function of invaginated caveolae and clathrin-coated pits, including the caveolae-dependent endocytosis and clathrin-dependent endocytosis. The role of cholesterol in caveolae-dependent and clathrin-dependent endocytosis can be investigated by using methyl beta cyclodextrin (MβCD) to remove cholesterol from the plasma membrane. In biology, caveolae (Latin for little caves) are small invaginations of the plasma membrane in many cell types, especially in endothelial cells. ... Endocytosis (IPA: ) is a process whereby cells absorb material (molecules such as proteins) from the outside by engulfing it with their cell membrane. ... Methyl-β-cyclodextrin Molecular Structure Methyl-β-cyclodextrin Structure Cyclodextrins make up a family of cyclic oligosaccharides. ...


Synthesis and intake

The HMG-CoA reductase pathway

Cholesterol is required in the membrane of mammalian cells for normal cellular function, and is either synthesized in the endoplasmic reticulum, or derived from the diet, in which case it is delivered by the bloodstream in low-density lipoproteins. These are taken into the cell by LDL receptor-mediated endocytosis in clathrin-coated pits, and then hydrolysed in lysosomes. Download high resolution version (534x695, 17 KB) HMG-CoA reductase pathway ( cholesterol) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (534x695, 17 KB) HMG-CoA reductase pathway ( cholesterol) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ... Low-density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying somewhat in their size and contents, which carry cholesterol in the blood and around the body, for use by various cells. ... Brown and Goldstein won a Nobel Prize for their identification of the Low Density Lipoprotein (LDL) receptor 30 years ago whilst they were studying the disease familiar hypercholesterolaemia. ... Endocytosis (IPA: ) is a process whereby cells absorb material (molecules such as proteins) from the outside by engulfing it with their cell membrane. ...


Cholesterol is primarily synthesized from acetyl CoA through the HMG-CoA reductase pathway in many cells and tissues. About 20 – 25% of total daily production (~1 g/day) occurs in the liver; other sites of higher synthesis rates include the intestines, adrenal glands and reproductive organs. For a person of about 150 pounds (68 kg), typical total body content is about 35 g, typical daily internal production is about 1 g and typical daily dietary intake is 200 to 300 mg in the United States and societies adopting its dietary patterns. Of the cholesterol input to the intestines via bile production, 92-97% is reabsorbed in the intestines and recycled via enterohepatic circulation. Acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. ... The HMG-CoA reductase pathway, also known as MVA pathway or mevalonate-dependent (MAD) route, is an important cellular metabolic pathway present in virtually all organisms. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... BIC pen cap, about 1 gram. ... Look up day in Wiktionary, the free dictionary. ... For the bird, see Liver bird. ... The intestine is the portion of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... In mammals, the adrenal glands (also known as suprarenal glands) are the triangle-shaped endocrine glands that sit on top of the kidneys; their name indicates that position (ad-, near or at + -renes, kidneys). They are chiefly responsible for regulating the stress response through the synthesis of corticosteroids and catecholamines... A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis... BIC pen cap, about 1 gram. ... Enterohepatic circulation, is the excretion of a drug (or a metabolite of it) through the bile to be re-absorbed in the gut and sent again to the liver along the portal vein, so the excretion-reabsortion cycle can start again. ...


Konrad Bloch and Feodor Lynen shared the Nobel Prize in Physiology or Medicine in 1964 for their discoveries concerning the mechanism and regulation of the cholesterol and fatty acid metabolism. Konrad Emil Bloch (January 21, 1912 - October 15, 2000) was a German-American biochemist. ... Feodor Felix Konrad Lynen (6. ... Emil Adolf von Behring was the first person to receive the Nobel Prize in physiology or Medicine, for his work on the treatment of diphtheria. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ...


Regulation

Biosynthesis of cholesterol is directly regulated by the cholesterol levels present, though the homeostatic mechanisms involved are only partly understood. A higher intake from food leads to a net decrease in endogenous production, while lower intake from food has the opposite effect. The main regulatory mechanism is the sensing of intracellular cholesterol in the endoplasmic reticulum by the protein SREBP (Sterol Regulatory Element Binding Protein 1 and 2). In the presence of cholesterol, SREBP is bound to two other proteins: SCAP (SREBP-cleavage activating protein) and Insig1. When cholesterol levels fall, Insig-1 dissociates from the SREBP-SCAP complex, allowing the complex to migrate to the Golgi apparatus, where SREBP is cleaved by S1P and S2P (site 1/2 protease), two enzymes that are activated by SCAP when cholesterol levels are low. The cleaved SREBP then migrates to the nucleus and acts as a transcription factor to bind to the SRE (sterol regulatory element) of a number of genes to stimulate their transcription. Among the genes transcribed are the LDL receptor and HMG-CoA reductase. The former scavenges circulating LDL from the bloodstream, whereas HMG-CoA reductase leads to an increase of endogenous production of cholesterol.[5] Homeostasis is the property of either an open system or a closed system,[1] especially a living organism, to regulate its internal environment to maintain a stable, constant condition. ... In cell biology, molecular biology and related fields, the word intracellular means inside the cell. It is used in contrast to extracellular (outside the cell). ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... SREBP Beginning with the discovery of the sterol regulatory element binding proteins (SREBPs) in 1993, a productive combination of biochemistry, molecular biology and genetics, has brought to light the complex mechanisms by which animal cells maintain the proper levels of intracellular lipid (fats and oils) in the face of widely... INSIG1 is short for insulin-induced gene 1; it is located on chromosome 7 (7q36). ... Micrograph of Golgi apparatus, visible as a stack of semicircular black rings near the bottom. ... In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... Brown and Goldstein won a Nobel Prize for their identification of the Low Density Lipoprotein (LDL) receptor 30 years ago whilst they were studying the disease familiar hypercholesterolaemia. ... The HMG-CoA reductase pathway, also known as MVA pathway or mevalonate-dependent (MAD) route, is an important cellular metabolic pathway present in virtually all organisms. ...


A large part of this mechanism was clarified by Dr Michael S. Brown and Dr Joseph L. Goldstein in the 1970s. They received the Nobel Prize in Physiology or Medicine for their work in 1985.[5] Dr. Michael S. Brown (b. ... Joseph L. Goldstein (b. ... Emil Adolf von Behring was the first person to receive the Nobel Prize in physiology or Medicine, for his work on the treatment of diphtheria. ...


The average amount of blood cholesterol varies with age, typically rising gradually until one is about 60 years old. There appear to be seasonal variations in cholesterol levels in humans, more, on average, in winter.[6]


Excretion

Cholesterol is excreted from the liver in bile and reabsorbed from the intestines. Under certain circumstances, when more concentrated, as in the gallbladder, it crystallises and is the major constituent of most gallstones, although lecithin and bilirubin gallstones also occur less frequently. For the bird, see Liver bird. ... Bile (or gall) is a bitter, yellow or green alkaline fluid secreted by hepatocytes from the liver of most vertebrates. ... The gallbladder (or cholecyst, sometimes gall bladder) is a pear-shaped organ that stores about 50 ml of bile (or gall) until the body needs it for digestion. ... This article does not cite any references or sources. ... Lecithin is mostly a mixture of glycolipids, triglycerides, and phospholipids (e. ... Bilirubin is a yellow breakdown product of normal heme catabolism. ...


Body fluids

Cholesterol is minimally soluble in water; it cannot dissolve and travel in the water-based bloodstream. Instead, it is transported in the bloodstream by lipoproteins - protein "molecular-suitcases" that are water-soluble and carry cholesterol and triglycerides internally. The apolipoproteins forming the surface of the given lipoprotein particle determine from what cells cholesterol will be removed and to where it will be supplied. Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... A lipoprotein is a biochemical assembly that contains both proteins and lipids. ... Example of an unsaturated fat triglyceride. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


The largest lipoproteins, which primarily transport fats from the intestinal mucosa to the liver, are called chylomicrons. They carry mostly fats in the form of triglycerides and cholesterol. In the liver, chylomicron particles release triglycerides and some cholesterol. The liver converts unburned food metabolites into very low density lipoproteins (VLDL) and secretes them into plasma where they are converted to low-density lipoprotein (LDL) particles and non-esterified fatty acids, which can affect other body cells. In healthy individuals, the relatively few LDL particles are large. In contrast, large numbers of small dense LDL (sdLDL) particles are strongly associated with the presence of atheromatous disease within the arteries. For this reason, LDL is referred to as "bad cholesterol". In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... The mucous membranes (or mucosa) are linings of ectodermic origin, covered in epithelium, that line various body cavities and internal organs. ... Chylomicrons are large lipoprotein particles (having a diameter of 75 to 1,200nm) that are created by the absorptive cells of the small intestine. ... Example of an unsaturated fat triglyceride. ... For the bird, see Liver bird. ... Low-density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying somewhat in their size and contents, which carry cholesterol in the blood and around the body, for use by various cells. ... In pathology, an atheroma (plural: atheromata) is an accumulation and swelling (-oma) in artery walls that is made up of cells, or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. ...


The 1987 report of National Cholesterol Education Program, Adult Treatment Panels suggest the total blood cholesterol level should be: <200 mg/dl normal blood cholesterol, 200-239 mg/dl borderline-high, >240 mg/dl high cholesterol.[7] The National Cholesterol Education Program is a program managed by the National Heart, Lung and Blood Institute, a division of the National Institutes of Health. ...


High-density lipoprotein (HDL) particles transport cholesterol back to the liver for excretion, but vary considerably in their effectiveness for doing this. Having large numbers of large HDL particles correlates with better health outcomes, and hence it is commonly called "good cholesterol". In contrast, having small amounts of large HDL particles is independently associated with atheromatous disease progression within the arteries. High density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size and contents, that carry cholesterol from the bodys tissues to the liver. ... In pathology, an atheroma (plural: atheromata) is an accumulation and swelling (-oma) in artery walls that is made up of cells, or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. ...


Clinical significance

Hypercholesterolemia

Conditions with elevated concentrations of oxidized LDL particles, especially "small dense LDL" (sdLDL) particles, are associated with atheroma formation in the walls of arteries, a condition known as atherosclerosis, which is the principal cause of coronary heart disease and other forms of cardiovascular disease. In contrast, HDL particles (especially large HDL) have been identified as a mechanism by which cholesterol and inflammatory mediators can be removed from atheroma. Increased concentrations of HDL correlate with lower rates of atheroma progressions and even regression. The relation of cholesterol to CHD, termed the "lipid hypothesis," is still hotly debated. Hypercholesterolemia (literally: high blood cholesterol) is the presence of high levels of cholesterol in the blood [1]. It is not a disease but a metabolic derangement that can be secondary to many diseases and can contribute to many forms of disease, most notably cardiovascular disease. ... The lipid hypothesis was one of two hypotheses developed in the 1850s to explain the pathogenesis of atherosclerosis. ... In pathology, an atheroma (plural: atheromata) is an accumulation and swelling (-oma) in artery walls that is made up of cells, or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. ... Section of an artery For other uses, see Artery (disambiguation). ... This article does not cite any references or sources. ... Cardiovascular disease refers to the class of diseases that involve the heart or blood vessels (arteries and veins). ... This article does not cite any references or sources. ... The lipid hypothesis was one of two hypotheses developed in the 1850s to explain the pathogenesis of atherosclerosis. ...


Elevated levels of the lipoprotein fractions, LDL, IDL and VLDL are regarded as atherogenic (prone to cause atherosclerosis).[citation needed] Levels of these fractions, rather than the total cholesterol level, correlate with the extent and progress of atherosclerosis. Conversely, the total cholesterol can be within normal limits, yet be made up primarily of small LDL and small HDL particles, under which conditions atheroma growth rates would still be high. In contrast, however, if LDL particle number is low (mostly large particles) and a large percentage of the HDL particles are large, then atheroma growth rates are usually low, even negative, for any given total cholesterol concentration.[citation needed]


Multiple human trials utilizing HMG-CoA reductase inhibitors, known as statins, have repeatedly confirmed that changing lipoprotein transport patterns from unhealthy to healthier patterns significantly lowers cardiovascular disease event rates, even for people with cholesterol values currently considered low for adults. As a result, people with a history of cardiovascular disease may derive benefit from statins irrespective of their cholesterol levels,[8] and in men without cardiovascular disease there is benefit from lowering abnormally high cholesterol levels ("primary prevention").[9] Primary prevention in women is practiced only by extension of the findings in studies on men,[10] since in women, none of the large statin trials has shown a reduction in overall mortality or in cardiovascular end points.[11] Lovastatin, the first statin to be marketed The statins form a class of hypolipidemic agents. ...


The American Heart Association provides a set of guidelines for total (fasting) blood cholesterol levels and risk for heart disease:[12] The American Heart Association (AHA) is a non-profit organization in the United States that fosters appropriate cardiac care in an effort to reduce disability and deaths caused by cardiovascular disease and stroke American Stroke Association Web site. ...

Level mg/dL Level mmol/L Interpretation
<200 <5.2 Desirable level corresponding to lower risk for heart disease
200-239 5.2-6.2 Borderline high risk
>240 >6.2 High risk

However, as today's testing methods determine LDL ("bad") and HDL ("good") cholesterol separately, this simplistic view has become somewhat outdated. The desirable LDL level is considered to be less than 100 mg/dL (2.6 mmol/L)[citation needed] , although a newer target of <70 mg/dL can be considered in higher risk individuals based on some of the above-mentioned trials. A ratio of total cholesterol to HDL — another useful measure — of far less than 5:1 is thought to be healthier. Of note, typical LDL values for children before fatty streaks begin to develop is 35 mg/dL. The milligram (symbol mg) is an SI unit of mass. ... A decilitre (or deciliter), abbreviated dL or dl, is one tenth of a litre, or 1×10&#8722;4 m3, or 100 millilitre. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... The litre or liter (see spelling differences) is a unit of volume. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... The litre or liter (see spelling differences) is a unit of volume. ... Fatty streak is the term generally given to the earliest stages of atheroma, as viewed at autopsy, looking at the inner surface of arteries, without magnification. ...


Most testing methods for LDL do not actually measure LDL in their blood, much less particle size. For cost reasons, LDL values have long been estimated using the Friedewald formula: [total cholesterol] − [total HDL] − 20% of the triglyceride value = estimated LDL. The basis of this is that Total cholesterol is defined as the sum of HDL, LDL, and VLDL. Ordinarily just the total, HDL, and triglycerides are actually measured. The VLDL is estimated as one-fifth of the triglycerides. It is important to fast for at least 8-12 hours before the blood test because the triglyceride level varies significantly with food intake. Example of an unsaturated fat triglyceride. ...


Given the well-recognized role of cholesterol in cardiovascular disease, it is surprising that some studies have shown an inverse correlation between cholesterol levels and mortality in subjects over 50 years of age — an 11% increase overall and 14% increase in CVD mortality per 1 mg/dL per year drop in cholesterol levels. In the Framingham Heart Study, the researchers attributed this phenomenon to the fact that people with severe chronic diseases or cancer tend to have below-normal cholesterol levels.[13] This explanation is not supported by the Vorarlberg Health Monitoring and Promotion Programme, in which men of all ages and women over 50 lower cholesterol levels with very low cholesterol were increasingly likely to die of cancer, liver diseases, and mental diseases. This result indicates that the low cholesterol effect occurs even among younger respondents, contradicting the previous assessment among cohorts of older people that this is a proxy or marker for frailty occurring with age.[14] The Framingham Heart Study is a cardiovascular study based in Framingham, Massachusetts. ...


A small group of scientists, united in The International Network of Cholesterol Skeptics, continues to question the link between cholesterol and atherosclerosis.[15] However, the vast majority of doctors and medical scientists accepts the link as fact.[16] The International Network of Cholesterol Skeptics (or THINCS) is a group of scientists, physicians, and other academicians from around the world who oppose regarding the lipid hypothesis as proven fact. ...


Hypocholesterolemia

Abnormally low levels of cholesterol are termed hypocholesterolemia. Research into the causes of this state is relatively limited, and while some studies suggest a link with depression, cancer and cerebral hemorrhage it is unclear whether the low cholesterol levels are a cause for these conditions or an epiphenomenon[1]. Hypocholesterolemia is the presence of abnormally low (hypo-) levels of cholesterol in the blood (-emia). ... In everyday language depression refers to any downturn in mood, which may be relatively transitory and perhaps due to something trivial. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... A cerebral hemorrhage is a bleed into the substance of the cerebrum. ... An epiphenomenon is a secondary phenomenon that occurs alongside a primary phenomenon. ...


Food sources

Cholesterol is found in animal fats: all food containing animal fats contains cholesterol; food not containing animal fats either contains no cholesterol or negligible amounts. Major dietary sources of cholesterol include eggs, beef and poultry.[17]


Plants have trace amounts of cholesterol, so even a vegan diet, which includes no animal foods, has traces of cholesterol. However, the amounts are very small. For example, to ingest the amount of cholesterol in one egg, one would need to drink about 9.6 litres (19.57 pounds) of pure peanut oil.[12] [18] Hens kept in cramped conditions — the avoidance of animal suffering is the primary motivation of people who become vegans A vegan is a person who avoids the ingestion or use of animal products. ...


Plant products (e.g. flax seed, peanut), also contain cholesterol-like compounds, phytosterols, which are suggested to help lower serum cholesterol.[19] Binomial name Linum usitatissimum L. Linnaeus, 17?? Common flax (also known as linseed) is a member of the Linaceae family, which includes about 150 plant species widely distributed around the world. ... Binomial name L. This article is about the legume. ... β-sitosterol Phytosterols (also called plant sterols) are a group of steroid alcohol, phytochemicals naturally occurring in plants. ... Look up Serum in Wiktionary, the free dictionary. ...


Cholesteric liquid crystals

Some cholesterol derivatives, (among other simple cholesteric lipids) are known to generate the liquid crystalline cholesteric phase. The cholesteric phase is in fact a chiral nematic phase, and changes colour when its temperature changes. Therefore, cholesterol derivatives are commonly used in liquid crystal thermometers and temperature-sensitive paints. Schlieren texture of Liquid Crystal nematic phase Liquid crystals are substances that exhibit a phase of matter that has properties between those of a conventional liquid, and those of a solid crystal. ... The term chiral (pronounced ) is used to describe an object which is non-superimposable on its mirror image. ... Schlieren texture of Liquid Crystal nematic phase Liquid crystals are substances that exhibit a phase of matter that has properties between those of a conventional liquid, and those of a solid crystal. ... A common mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ...


See also

Example of an unsaturated fat triglyceride. ... Diet may play an important role in causing or preventing heart disease. ...

Additional images

References

  1. ^ a b Safety (MSDS) data for cholesterol. Retrieved on 2007-10-20.
  2. ^ Olson RE (1998). "Discovery of the lipoproteins, their role in fat transport and their significance as risk factors". J. Nutr. 128 (2 Suppl): 439S-443S. PMID 9478044. 
  3. ^ Smith LL (1991). "Another cholesterol hypothesis: cholesterol as antioxidant". Free Radic. Biol. Med. 11 (1): 47–61. PMID 1937129. 
  4. ^ Haines TH (2001). "Do sterols reduce proton and sodium leaks through lipid bilayers?". Prog. Lipid Res. 40 (4): 299–324. PMID 11412894. 
  5. ^ a b Anderson RG. (2003). "Joe Goldstein and Mike Brown: from cholesterol homeostasis to new paradigms in membrane biology.". Trends Cell Biol 13: 534 – 9. PMID 14507481. 
  6. ^ Ockene IS, Chiriboga DE, Stanek EJ 3rd, Harmatz MG, Nicolosi R, Saperia G, Well AD, Freedson P, Merriam PA, Reed G, Ma Y, Matthews CE, Hebert JR. (2004). "Seasonal variation in serum cholesterol levels: treatment implications and possible mechanisms.". Arch Intern Med 164: 863 – 70. PMID 15111372. 
  7. ^ (1988) "Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. The Expert Panel". Arch. Intern. Med. 148 (1): 36–69. PMID 3422148. 
  8. ^ (2002) "MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial". Lancet 360 (9326): 7-22. PMID 12114036. 
  9. ^ Shepherd J, Cobbe SM, Ford I, et al (1995). "Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia. West of Scotland Coronary Prevention Study Group". N. Engl. J. Med. 333 (20): 1301-7. PMID 7566020. 
  10. ^ Grundy SM (2007). "Should women be offered cholesterol lowering drugs to prevent cardiovascular disease? Yes". BMJ 334 (7601): 982. doi:10.1136/bmj.39202.399942.AD. PMID 17494017. 
  11. ^ Kendrick M (2007). "Should women be offered cholesterol lowering drugs to prevent cardiovascular disease? No". BMJ 334 (7601): 983. doi:10.1136/bmj.39202.397488.AD. PMID 17494018. 
  12. ^ a b "About cholesterol" - American Heart Association
  13. ^ Anderson KM., Castelli WP, Levy D. (1987). "Cholesterol and mortality. 30 years of follow-up from the Framingham study.". JAMA 257: 2176 – 80. PMID 3560398. 
  14. ^ Ulmer H., Kelleher C., Diem G., Concin H. (2004). "Why Eve is not Adam: prospective follow-up in 149650 women and men of cholesterol and other risk factors related to cardiovascular and all-cause mortality.". J Women's Health (Larchmt) 13: 41 – 53. PMID 15006277. 
  15. ^ Uffe Ravnskov. The Cholesterol Myths : Exposing the Fallacy that Saturated Fat and Cholesterol Cause Heart Disease. New Trends Publishing, Incorporated. ISBN 0-96708-970-0. 
  16. ^ Daniel Steinberg. The Cholesterol Wars: The Cholesterol Skeptics vs the Preponderance of Evidence. Boston: Academic Press. ISBN 0-12-373979-9. 
  17. ^ Nutrition and Your Health: Dietary Guidelines for Americans. Table E-18. Dietary Sources of Cholesterol Listed in Decreasing Order.
  18. ^ Behrman EJ, Gopalan V. Cholesterol and plants. J Chem Educ 2005;82:1791-1793. PDF
  19. ^ Ostlund RE, Racette, SB, and Stenson WF (2003). "Inhibition of cholesterol absorption by phytosterol-replete wheat germ compared with phytosterol-depleted wheat germ". Am J Clin Nutr 77 (6): 1385-1589. PMID 12791614. 

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 293rd day of the year (294th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

Cholesterol. ... The major membrane lipids PtdCho - Phosphatidylcholine; PtdEtn - Phosphatidylethanolamine; PtdIns - Phosphatidylinositol; PtdSer - Phosphatidylserine. ... Sterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring. ... Adosterol is an iodine-containing sterol. ... Chemical structure of cholecalciferol Cholecalciferol is a form of Vitamin D, also called vitamin D3. ... Ergocalciferol (Deltalin®, Eli Lilly and Company) is a form of Vitamin D, also called vitamin D2. ... Vitamin D is a fat-soluble steroid hormone precursor that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Fusidic acid is an antibacterial antibiotic used particularly for eye and skin infections. ... Lanosterol is a tetracyclic triterpenoid which is the compound from which all steroids are derived. ... β-sitosterol Ergosterol. ... Solanine is a glycoalkaloid poison found in species of the nightshade family. ...


  Results from FactBites:
 
Cholesterol and Bile Metabolism (2843 words)
Cholesterol is an extremely important biological molecule that has roles in membrane structure as well as being a precursor for the synthesis of the steroid hormones and bile acids.
Cholesterol is transported in the plasma predominantly as cholesteryl esters associated with lipoproteins.
However, the excretion of cholesterol in the form of bile acids is insufficient to compensate for an excess dietary intake of cholesterol.
Lower Your Cholesterol - High Cholesterol Information (304 words)
Cholesterol, a fatty substance (a lipid) that resides in the bloodstream, has two sources; it is either produced by the body or consumed from food products.
The goal of cholesterol management in the body, is to have a high level of HDL and a low level of LDL cholesterol.
Cholesterol lowering medications may be prescribed by your doctor if your cholesterol levels do not reach healthy levels thru diet and exercise alone.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m