A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H)
and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of
2:1 (as in water); in other words, with the empirical formula Cm(H2O)n
(where m may be different from n). This formula holds true for
monosaccharides. Some exceptions exist; for example, deoxyribose, a
sugar component of DNA, has the empirical formula C5H10O4. The
carbohydrates are technically hydrates of carbon; structurally it
is more accurate to view them as aldoses and ketoses .
The term is most common in biochemistry, where it is a synonym of
'saccharide', a group that includes sugars, starch, and cellulose. The
saccharides are divided into four chemical groups: monosaccharides,
disaccharides, oligosaccharides, and polysaccharides. Monosaccharides
and disaccharides, the smallest (lower molecular weight)
carbohydrates, are commonly referred to as sugars. The word
saccharide comes from the Greek word σάκχαρον (sákkharon),
meaning "sugar". While the scientific nomenclature of carbohydrates
is complex, the names of the monosaccharides and disaccharides very
often end in the suffix -ose. For example, grape sugar is the
monosaccharide glucose, cane sugar is the disaccharide sucrose, and
milk sugar is the disaccharide lactose.
Carbohydrates perform numerous roles in living organisms.
Polysaccharides serve for the storage of energy (e.g. starch and
glycogen) and as structural components (e.g. cellulose in plants and
chitin in arthropods). The 5-carbon monosaccharide ribose is an
important component of coenzymes (e.g. ATP, FAD and NAD) and the
backbone of the genetic molecule known as RNA. The related deoxyribose
is a component of DNA. Saccharides and their derivatives include many
other important biomolecules that play key roles in the immune system,
fertilization, preventing pathogenesis, blood clotting, and
Carbohydrates are found in a wide variety of foods. The important
sources are cereals (wheat, maize, rice), potatoes, sugarcane, fruits,
table sugar (sucrose), bread, milk, etc.
Starch and sugar are the
important carbohydrates in our diet.
Starch is abundant in potatoes,
maize, rice and other cereals.
Sugar appears in our diet mainly as
sucrose (table sugar), which is added to drinks and many prepared
foods such as jam, biscuits and cakes, and glucose and fructose which
occur naturally in many fruits and some vegetables.
Glycogen is a carbohydrate found in the liver and muscles (as animal
Cellulose in the cell wall of all plant tissue is a
carbohydrate. It is important in our diet as fibre which helps to
maintain a healthy digestive system.
4.1 Classification of monosaccharides
4.2 Ring-straight chain isomerism
4.3 Use in living organisms
6.2 Effects of dietary carbohydrate restriction
9 See also
12 External links
In scientific literature, the term "carbohydrate" has many synonyms,
like "sugar" (in the broad sense), "saccharide", "ose",
"glucide", "hydrate of carbon" or "polyhydroxy compounds with
aldehyde or ketone". Some of these terms, specially "carbohydrate"
and "sugar", are also used with other meanings.
In food science and in many informal contexts, the term "carbohydrate"
often means any food that is particularly rich in the complex
carbohydrate starch (such as cereals, bread and pasta) or simple
carbohydrates, such as sugar (found in candy, jams, and desserts).
Often in lists of nutritional information, such as the USDA National
Nutrient Database, the term "carbohydrate" (or "carbohydrate by
difference") is used for everything other than water, protein, fat,
ash, and ethanol. This will include chemical compounds such as
acetic or lactic acid, which are not normally considered
carbohydrates. It also includes dietary fiber which is a carbohydrate
but which does not contribute much in the way of food energy
(calories), even though it is often included in the calculation of
total food energy just as though it were a sugar.
In the strict sense, "sugar" is applied for sweet, soluble
carbohydrates, many of which are used in food.
Formerly the name "carbohydrate" was used in chemistry for any
compound with the formula Cm (H2O)n. Following this definition, some
chemists considered formaldehyde (CH2O) to be the simplest
carbohydrate, while others claimed that title for
glycolaldehyde. Today, the term is generally understood in the
biochemistry sense, which excludes compounds with only one or two
carbons and includes many biological carbohydrates which deviate from
this formula. For example, while the above representative formulas
would seem to capture the commonly known carbohydrates, ubiquitous and
abundant carbohydrates often deviate from this. For example,
carbohydrates often display chemical groups such as: N-acetyl (e.g.
chitin), sulphate (e.g. glycosaminoglycans), carboxylic acid (e.g.
sialic acid) and deoxy modifications (e.g. fucose and sialic acid).
Natural saccharides are generally built of simple carbohydrates called
monosaccharides with general formula (CH2O)n where n is three or more.
A typical monosaccharide has the structure
H–(CHOH)x(C=O)–(CHOH)y–H, that is, an aldehyde or ketone with
many hydroxyl groups added, usually one on each carbon atom that is
not part of the aldehyde or ketone functional group. Examples of
monosaccharides are glucose, fructose, and glyceraldehydes. However,
some biological substances commonly called "monosaccharides" do not
conform to this formula (e.g. uronic acids and deoxy-sugars such as
fucose) and there are many chemicals that do conform to this formula
but are not considered to be monosaccharides (e.g. formaldehyde CH2O
and inositol (CH2O)6).
The open-chain form of a monosaccharide often coexists with a closed
ring form where the aldehyde/ketone carbonyl group carbon (C=O) and
hydroxyl group (–OH) react forming a hemiacetal with a new C–O–C
Monosaccharides can be linked together into what are called
polysaccharides (or oligosaccharides) in a large variety of ways. Many
carbohydrates contain one or more modified monosaccharide units that
have had one or more groups replaced or removed. For example,
deoxyribose, a component of DNA, is a modified version of ribose;
chitin is composed of repeating units of N-acetyl glucosamine, a
nitrogen-containing form of glucose.
Carbohydrates are polyhydroxy aldehydes, ketones, alcohols, acids,
their simple derivatives and their polymers having linkages of the
acetal type. They may be classified according to their degree of
polymerization and may be divided initially into three principal
groups, namely sugars, oligosaccharides and polysaccharides
The major dietary carbohydrates
Glucose, galactose, fructose, xylose
Sucrose, lactose, maltose, trehalose
Raffinose, stachyose, fructo-oligosaccharides
Amylose, amylopectin, modified starches
Cellulose, hemicellulose, pectins, hydrocolloids
DP * = Degree of polymerization
Main article: Monosaccharide
D-glucose is an aldohexose with the formula (C·H2O)6. The red atoms
highlight the aldehyde group and the blue atoms highlight the
asymmetric center furthest from the aldehyde; because this -OH is on
the right of the Fischer projection, this is a D sugar.
Monosaccharides are the simplest carbohydrates in that they cannot be
hydrolyzed to smaller carbohydrates. They are aldehydes or ketones
with two or more hydroxyl groups. The general chemical formula of an
unmodified monosaccharide is (C•H2O)n, literally a "carbon hydrate".
Monosaccharides are important fuel molecules as well as building
blocks for nucleic acids. The smallest monosaccharides, for which n=3,
are dihydroxyacetone and D- and L-glyceraldehydes.
Classification of monosaccharides
The α and β anomers of glucose. Note the position of the hydroxyl
group (red or green) on the anomeric carbon relative to the CH2OH
group bound to carbon 5: they either have identical absolute
configurations (R,R or S,S) (α), or opposite absolute configurations
(R,S or S,R) (β).
Monosaccharides are classified according to three different
characteristics: the placement of its carbonyl group, the number of
carbon atoms it contains, and its chiral handedness. If the carbonyl
group is an aldehyde, the monosaccharide is an aldose; if the carbonyl
group is a ketone, the monosaccharide is a ketose. Monosaccharides
with three carbon atoms are called trioses, those with four are called
tetroses, five are called pentoses, six are hexoses, and so on.
These two systems of classification are often combined. For example,
glucose is an aldohexose (a six-carbon aldehyde), ribose is an
aldopentose (a five-carbon aldehyde), and fructose is a ketohexose (a
Each carbon atom bearing a hydroxyl group (-OH), with the exception of
the first and last carbons, are asymmetric, making them stereo centers
with two possible configurations each (R or S). Because of this
asymmetry, a number of isomers may exist for any given monosaccharide
formula. Using Le Bel-van't Hoff rule, the aldohexose D-glucose, for
example, has the formula (C·H2O)6, of which four of its six carbons
atoms are stereogenic, making D-glucose one of 24=16 possible
stereoisomers. In the case of glyceraldehydes, an aldotriose, there is
one pair of possible stereoisomers, which are enantiomers and epimers.
1, 3-dihydroxyacetone, the ketose corresponding to the aldose
glyceraldehydes, is a symmetric molecule with no stereo centers. The
assignment of D or L is made according to the orientation of the
asymmetric carbon furthest from the carbonyl group: in a standard
Fischer projection if the hydroxyl group is on the right the molecule
is a D sugar, otherwise it is an L sugar. The "D-" and "L-" prefixes
should not be confused with "d-" or "l-", which indicate the direction
that the sugar rotates plane polarized light. This usage of "d-" and
"l-" is no longer followed in carbohydrate chemistry.
Ring-straight chain isomerism
Glucose can exist in both a straight-chain and ring form.
The aldehyde or ketone group of a straight-chain monosaccharide will
react reversibly with a hydroxyl group on a different carbon atom to
form a hemiacetal or hemiketal, forming a heterocyclic ring with an
oxygen bridge between two carbon atoms. Rings with five and six atoms
are called furanose and pyranose forms, respectively, and exist in
equilibrium with the straight-chain form.
During the conversion from straight-chain form to the cyclic form, the
carbon atom containing the carbonyl oxygen, called the anomeric
carbon, becomes a stereogenic center with two possible configurations:
The oxygen atom may take a position either above or below the plane of
the ring. The resulting possible pair of stereoisomers is called
anomers. In the α anomer, the -OH substituent on the anomeric carbon
rests on the opposite side (trans) of the ring from the CH2OH side
branch. The alternative form, in which the CH2OH substituent and the
anomeric hydroxyl are on the same side (cis) of the plane of the ring,
is called the β anomer.
Use in living organisms
Monosaccharides are the major source of fuel for metabolism, being
used both as an energy source (glucose being the most important in
nature) and in biosynthesis. When monosaccharides are not immediately
needed by many cells they are often converted to more space-efficient
forms, often polysaccharides. In many animals, including humans, this
storage form is glycogen, especially in liver and muscle cells. In
plants, starch is used for the same purpose. The most abundant
carbohydrate, cellulose, is a structural component of the cell wall of
plants and many forms of algae.
Ribose is a component of RNA.
Deoxyribose is a component of DNA.
Lyxose is a component of lyxoflavin
found in the human heart.
Ribulose and xylulose occur in the
pentose phosphate pathway. Galactose, a component of milk sugar
lactose, is found in galactolipids in plant cell membranes and in
glycoproteins in many tissues.
Mannose occurs in human metabolism,
especially in the glycosylation of certain proteins. Fructose, or
fruit sugar, is found in many plants and in humans, it is metabolized
in the liver, absorbed directly into the intestines during digestion,
and found in semen. Trehalose, a major sugar of insects, is rapidly
hydrolyzed into two glucose molecules to support continuous flight.
Sucrose, also known as table sugar, is a common disaccharide. It is
composed of two monosaccharides: D-glucose (left) and D-fructose
Main article: Disaccharide
Two joined monosaccharides are called a disaccharide and these are the
simplest polysaccharides. Examples include sucrose and lactose. They
are composed of two monosaccharide units bound together by a covalent
bond known as a glycosidic linkage formed via a dehydration reaction,
resulting in the loss of a hydrogen atom from one monosaccharide and a
hydroxyl group from the other. The formula of unmodified disaccharides
is C12H22O11. Although there are numerous kinds of disaccharides, a
handful of disaccharides are particularly notable.
Sucrose, pictured to the right, is the most abundant disaccharide, and
the main form in which carbohydrates are transported in plants. It is
composed of one D-glucose molecule and one D-fructose molecule. The
systematic name for sucrose,
O-α-D-glucopyranosyl-(1→2)-D-fructofuranoside, indicates four
Its monosaccharides: glucose and fructose
Their ring types: glucose is a pyranose and fructose is a furanose
How they are linked together: the oxygen on carbon number 1 (C1) of
α-D-glucose is linked to the C2 of D-fructose.
The -oside suffix indicates that the anomeric carbon of both
monosaccharides participates in the glycosidic bond.
Lactose, a disaccharide composed of one D-galactose molecule and one
D-glucose molecule, occurs naturally in mammalian milk. The systematic
name for lactose is O-β-D-galactopyranosyl-(1→4)-D-glucopyranose.
Other notable disaccharides include maltose (two D-glucoses linked
α-1,4) and cellulobiose (two D-glucoses linked β-1,4). Disaccharides
can be classified into two types: reducing and non-reducing
disaccharides. If the functional group is present in bonding with
another sugar unit, it is called a reducing disaccharide or biose.
This article may lend undue weight to certain ideas, incidents, or
controversies. Please help to create a more neutral presentation, with
details put in their proper context. Discuss and resolve this issue
before removing this message. (June 2015)
Grain products: rich sources of carbohydrates
Carbohydrate consumed in food yields 3.87 calories of energy per gram
for simple sugars, and 3.57 to 4.12 calories per gram for complex
carbohydrate in most other foods. Relatively high levels of
carbohydrate are associated with processed foods or refined foods made
from plants, including sweets, cookies and candy, table sugar, honey,
soft drinks, breads and crackers, jams and fruit products, pastas and
breakfast cereals. Lower amounts of carbohydrate are usually
associated with unrefined foods, including beans, tubers, rice, and
unrefined fruit. Animal-based foods generally have the lowest
carbohydrate levels, although milk does contain a high proportion of
Organisms typically cannot metabolize all types of carbohydrate to
Glucose is a nearly universal and accessible source of
energy. Many organisms also have the ability to metabolize other
monosaccharides and disaccharides but glucose is often metabolized
first. In Escherichia coli, for example, the lac operon will express
enzymes for the digestion of lactose when it is present, but if both
lactose and glucose are present the lac operon is repressed, resulting
in the glucose being used first (see: Diauxie). Polysaccharides are
also common sources of energy. Many organisms can easily break down
starches into glucose; most organisms, however, cannot metabolize
cellulose or other polysaccharides like chitin and arabinoxylans.
These carbohydrate types can be metabolized by some bacteria and
protists. Ruminants and termites, for example, use microorganisms to
process cellulose. Even though these complex carbohydrates are not
very digestible, they represent an important dietary element for
humans, called dietary fiber. Fiber enhances digestion, among other
Based on the effects on risk of heart disease and obesity in otherwise
healthy middle-aged adults, the
Institute of Medicine
Institute of Medicine recommends
that American and Canadian adults get between 45–65% of dietary
energy from whole-grain carbohydrates. The Food and Agriculture
World Health Organization
World Health Organization jointly recommend that
national dietary guidelines set a goal of 55–75% of total energy
from carbohydrates, but only 10% directly from sugars (their term for
Nutritionists often refer to carbohydrates as either simple or
complex. However, the exact distinction between these groups can be
ambiguous. The term complex carbohydrate was first used in the U.S.
Senate Select Committee on
Nutrition and Human Needs publication
Dietary Goals for the United States (1977) where it was intended to
distinguish sugars from other carbohydrates (which were perceived to
be nutritionally superior). However, the report put "fruit,
vegetables and whole-grains" in the complex carbohydrate column,
despite the fact that these may contain sugars as well as
polysaccharides. This confusion persists as today some nutritionists
use the term complex carbohydrate to refer to any sort of digestible
saccharide present in a whole food, where fiber, vitamins and minerals
are also found (as opposed to processed carbohydrates, which provide
energy but few other nutrients). The standard usage, however, is to
classify carbohydrates chemically: simple if they are sugars
(monosaccharides and disaccharides) and complex if they are
polysaccharides (or oligosaccharides).
In any case, the simple vs. complex chemical distinction has little
value for determining the nutritional quality of carbohydrates.
Some simple carbohydrates (e.g. fructose) raise blood glucose slowly,
while some complex carbohydrates (starches), especially if processed,
raise blood sugar rapidly. The speed of digestion is determined by a
variety of factors including which other nutrients are consumed with
the carbohydrate, how the food is prepared, individual differences in
metabolism, and the chemistry of the carbohydrate.
The USDA's Dietary Guidelines for Americans 2010 call for moderate- to
high-carbohydrate consumption from a balanced diet that includes six
one-ounce servings of grain foods each day, at least half from whole
grain sources and the rest from enriched.
The glycemic index (GI) and glycemic load concepts have been developed
to characterize food behavior during human digestion. They rank
carbohydrate-rich foods based on the rapidity and magnitude of their
effect on blood glucose levels.
Glycemic index is a measure of how
quickly food glucose is absorbed, while glycemic load is a measure of
the total absorbable glucose in foods. The insulin index is a similar,
more recent classification method that ranks foods based on their
effects on blood insulin levels, which are caused by glucose (or
starch) and some amino acids in food.
Effects of dietary carbohydrate restriction
See also: Low-carbohydrate diet
Carbohydrates are a common source of energy in living organisms;
however, no single carbohydrate is an essential nutrient in
humans. Humans are able to obtain all of their energy requirement
from protein and fats, though the potential for some negative health
effects of extreme carbohydrate restriction remains, as the issue has
not been studied extensively yet. However, in the case of dietary
fiber – indigestible carbohydrates which are not a source of
energy – inadequate intake can lead to significant increases in
Following a diet consisting of very low amounts of daily carbohydrate
for several days will usually result in higher levels of blood ketone
bodies than an isocaloric diet with similar protein content. This
relatively high level of ketone bodies is commonly known as ketosis
and is very often confused with the potentially fatal condition often
seen in type 1 diabetics known as diabetic ketoacidosis. Somebody
suffering ketoacidosis will have much higher levels of blood ketone
bodies along with high blood sugar, dehydration and electrolyte
Long-chain fatty acids cannot cross the blood–brain barrier, but the
liver can break these down to produce ketones. However, the
medium-chain fatty acids octanoic and heptanoic acids can cross the
barrier and be used by the brain, which normally relies upon glucose
for its energy.
Gluconeogenesis allows humans to
synthesize some glucose from specific amino acids: from the glycerol
backbone in triglycerides and in some cases from fatty acids.
Carbohydrate metabolism denotes the various biochemical processes
responsible for the formation, breakdown and interconversion of
carbohydrates in living organisms.
The most important carbohydrate is glucose, a simple sugar
(monosaccharide) that is metabolized by nearly all known organisms.
Glucose and other carbohydrates are part of a wide variety of
metabolic pathways across species: plants synthesize carbohydrates
from carbon dioxide and water by photosynthesis storing the absorbed
energy internally, often in the form of starch or lipids. Plant
components are consumed by animals and fungi, and used as fuel for
cellular respiration. Oxidation of one gram of carbohydrate yields
approximately 4 kcal of energy, while the oxidation of one gram of
lipids yields about 9 kcal.
Energy obtained from metabolism (e.g.,
oxidation of glucose) is usually stored temporarily within cells in
the form of ATP. Organisms capable of aerobic respiration
metabolize glucose and oxygen to release energy with carbon dioxide
and water as byproducts.
Catabolism is the metabolic reaction which cells undergo to extract
energy. There are two major metabolic pathways of monosaccharide
catabolism: glycolysis and the citric acid cycle.
In glycolysis, oligo/polysaccharides are cleaved first to smaller
monosaccharides by enzymes called glycoside hydrolases. The
monosaccharide units can then enter into monosaccharide catabolism. In
some cases, as with humans, not all carbohydrate types are usable as
the digestive and metabolic enzymes necessary are not present.
Carbohydrate chemistry is a large and economically important branch of
organic chemistry. Some of the main organic reactions that involve
Lobry de Bruyn–van Ekenstein transformation
Pentose phosphate pathway
Western Kentucky University
Western Kentucky University (May 29, 2013). "WKU BIO 113
^ Solomon EP, Berg LR, Martin DW (2004). Biology. Cengage Learning.
p. 52. ISBN 978-0534278281 – via google.books.com.
National Institute of Standards and Technology
National Institute of Standards and Technology (2011). "Material
Measurement Library D-erythro-Pentose, 2-deoxy-". nist.gov.
^ a b
Long Island University
Long Island University (May 29, 2013). "The
Carbohydrates" (PDF). brooklyn.liu.edu.
Purdue University (May 29, 2013). "Carbohydrates: The
^ Flitsch SL, Ulijn RV (January 2003). "Sugars tied to the spot".
Nature. 421 (6920): 219–20. Bibcode:2003Natur.421..219F.
doi:10.1038/421219a. PMID 12529622.
^ a b Avenas P (2012). "Etymology of main polysaccharide names". In
Navard P. The European
Polysaccharide Network of Excellence (EPNOE)
(PDF). Wien: Springer-Verlag.
^ Maton A, Hopkins J, McLaughlin CW, Johnson S, Warner MQ, LaHart D,
Wright JD (1993). Human Biology and Health. Englewood Cliffs, New
Jersey: Prentice Hall. pp. 52–59.
^ USDA National Nutrient Database, 2015, p. 14
^ Fearon WF (1949). Introduction to
Biochemistry (2nd ed.). London:
^ USDA National Nutrient Database, 2015, p. 13
^ Coulter JM, Barnes CR, Cowles HC (1930). A Textbook of Botany for
Colleges and Universities.
^ Burtis CA, Ashwood ER, Tietz NW (2000). Tietz fundamentals of
^ Matthews CE, Van Holde KE, Ahern KG (1999).
Biochemistry (3rd ed.).
Benjamin Cummings. ISBN 0-8053-3066-6. [page needed]
^ "Chapter 1 – The role of carbohydrates in nutrition".
Carbohydrates in human nutrition. FAO Food and
Nutrition Paper - 66.
Food and Agriculture Organization
Food and Agriculture Organization of the United Nations.
^ Bertozzi CR, Rabuka D. "Structural Basis of Glycan Diversity".
Glycobiology (3rd ed.). Cold Spring Harbor (NY): Cold
Spring Harbor Laboratory Press. ISBN 978-1-621821-32-8.
^ Campbell NA, Williamson B, Heyden RJ (2006). Biology: Exploring
Life. Boston, Massachusetts: Pearson Prentice Hall.
^ Pigman W, Horton D (1972). "Chapter 1: Stereochemistry of the
Monosaccharides". In Pigman and Horton. The Carbohydrates: Chemistry
Biochemistry Vol 1A (2nd ed.). San Diego: Academic Press.
^ Pigman W, Anet E (1972). "Chapter 4: Mutarotations and Actions of
Acids and Bases". In Pigman and Horton. The Carbohydrates: Chemistry
Biochemistry Vol 1A (2nd ed.). San Diego: Academic Press.
^ "lyxoflavin". Merriam-Webster.
^ "Show Foods". usda.gov.
^ "Calculation of the
Energy Content of Foods –
Carbohydrate reference list" (PDF). www.diabetes.org.uk. Retrieved
October 30, 2016.
^ Pichon L, Huneau JF, Fromentin G, Tomé D (May 2006). "A
high-protein, high-fat, carbohydrate-free diet reduces energy intake,
hepatic lipogenesis, and adiposity in rats". The Journal of Nutrition.
136 (5): 1256–60. doi:10.1093/jn/136.5.1256.
^ Tighe P, Duthie G, Vaughan N, Brittenden J, Simpson WG, Duthie S,
Mutch W, Wahle K, Horgan G, Thies F (October 2010). "Effect of
increased consumption of whole-grain foods on blood pressure and other
cardiovascular risk markers in healthy middle-aged persons: a
randomized controlled trial". The American Journal of Clinical
Nutrition. 92 (4): 733–40. doi:10.3945/ajcn.2010.29417.
^ Food and
Nutrition Board (2002/2005). Dietary Reference Intakes for
Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein
and Amino Acids. Washington, D.C.: The National Academies Press. Page
769. ISBN 0-309-08537-3.
^ Joint WHO/FAO expert consultation (2003).  (PDF). Geneva: World
Health Organization. pp. 55–56. ISBN 92-4-120916-X.
^ Joint WHO/FAO expert consultation (1998), Carbohydrates in human
nutrition, chapter 1. ISBN 92-5-104114-8.
^ a b "Carbohydrates". The
Nutrition Source. Harvard School of Public
Health. Retrieved April 3, 2013.
^ Jenkins DJ, Jenkins AL, Wolever TM, Thompson LH, Rao AV (February
1986). "Simple and complex carbohydrates".
Nutrition Reviews. 44 (2):
^ DHHS and USDA, Dietary Guidelines for Americans 2010.
^ a b Westman EC (May 2002). "Is dietary carbohydrate essential for
human nutrition?". The American Journal of Clinical Nutrition. 75 (5):
951–3; author reply 953–4. doi:10.1093/ajcn/75.5.951a.
^ Park Y, Subar AF, Hollenbeck A, Schatzkin A (June 2011). "Dietary
fiber intake and mortality in the NIH-AARP diet and health study".
Archives of Internal Medicine. 171 (12): 1061–8.
doi:10.1001/archinternmed.2011.18. PMC 3513325 .
^ Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, Sears B (2006).
"Ketogenic low-carbohydrate diets have no metabolic advantage over
nonketogenic low-carbohydrate diets". The American Journal of Clinical
Nutrition. 83 (5): 1055–61. doi:10.1093/ajcn/83.5.1055.
^ Ebert D, Haller RG, Walton ME (2003). "
Energy contribution of
octanoate to intact rat brain metabolism measured by 13C nuclear
magnetic resonance spectroscopy". The Journal of Neuroscience. 23
(13): 5928–35. PMID 12843297.
^ Marin-Valencia I, Good LB, Ma Q, Malloy CR, Pascual JM (February
2013). "Heptanoate as a neural fuel: energetic and neurotransmitter
precursors in normal and glucose transporter I-deficient (G1D) brain".
Journal of Cerebral Blood Flow and Metabolism. 33 (2): 175–82.
doi:10.1038/jcbfm.2012.151. PMID 23072752.
^ Horn RS. "Integration of Metabolism". medbio.info.
^ Mehta S (9 October 2013). "Energetics of Cellular Respiration
Biochemistry Notes, Notes.
"Compolition of foods raw, processed, prepared" (PDF). United States
Department of Agriculture. September 2015. Retrieved October 30,
Wikimedia Commons has media related to Carbohydrates.
Wikiquote has quotations related to: Carbohydrate
Carbohydrates, including interactive models and animations (Requires
IUPAC-IUBMB Joint Commission on Biochemical Nomenclature (JCBN):
Glycosylation – The Virtual Library of
Biochemistry, Molecular Biology and Cell Biology
Glycomics Gateway, a collaboration between the Consortium
Glycomics and Nature Publishing Group
Metabolism, catabolism, anabolism
Primary nutritional groups
Glycolysis → Pyruvate decarboxylation →
Citric acid cycle
Citric acid cycle →
Oxidative phosphorylation (electron transport chain + ATP synthase)
Electron acceptors are other than oxygen
Glycolysis ⇄ Gluconeogenesis
Glycogenolysis ⇄ Glycogenesis
Pentose phosphate pathway
Fatty acid metabolism
Fatty acid degradation (Beta oxidation)
Fatty acid synthesis
Reverse cholesterol transport
Amino acid synthesis
Essential fatty acids
"Minerals" (Chemical elements)
Types of carbohydrates
Dextrin / Dextran
Fructose / Fructan
Galactose / Galactan
Glucose / Glucan
Levan beta 2→6