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Related to Fructose intolerance: lactose intolerance, Hereditary fructose intolerance




(lĕv`yəlōs'), or

fruit sugar,

simple sugar found in honey and in the fruit and other parts of plants. It is much sweeter than sucrosesucrose
, commonest of the sugars, a white, crystalline solid disaccharide (see carbohydrate) with a sweet taste, melting and decomposing at 186°C; to form caramel. It is known commonly as cane sugar, beet sugar, or maple sugar, depending upon its natural source.
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 (cane sugar). It is best obtained by hydrolysis of inulin, a polysaccharide found in dahlia bulbs and the Jerusalem artichoke. Chemically it is a monosaccharide (see carbohydratecarbohydrate,
any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds. These compounds are produced naturally by green plants from carbon dioxide and water (see photosynthesis).
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) with the empirical formula C6H12O6. It has the same formula as glucose but differs from it in structure (see isomerisomer
, in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of such compounds. Isomerism was first recognized by J. J. Berzelius in 1827.
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). It is often found with glucose in nature. Glucose and fructose are formed in equal amounts when sucrose is hydrolyzed by the enzyme invertase or by heating with dilute acid; the resulting equimolar mixture of fructose and glucose, called invert sugar, is the major component of honey. Fructose reacts with Fehling's solutionFehling's solution
, deep-blue, alkaline solution used to test for the presence of aldehydes (e.g., formaldehyde, HCHO) or other compounds that contain the aldehyde functional group, -CHO.
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 and can be differentiated from glucose by its reaction with lime water to form a water-insoluble precipitate, calcium fructosate. In solution, fructose exists as a ring compound in equilibrium with a straight-chain form.


A sugar that is the commonest of ketoses and the sweetest of the sugars. It is also known as d -fructose, d -fructopyranose, and levulose fruit sugar. It is found in free state, usually accompanied by d -glucose and sucrose in fruit juices, honey, and nectar of plant glands. d -Fructose is the principal sugar in seminal fluid. See Carbohydrate

Fructose is readily utilized by diabetic animals. In persons with diabetes mellitus or parenchymal hepatic disease, the impairment of fructose tolerance is relatively small and not at all comparable to the diminution in their tolerance to glucose. See Monosaccharide



(fruit sugar, levulose, (β-D-fructose), a colorless crystalline substance, with a sweet taste (1.5 times sweeter than saccharose and three times sweeter than glucose) and a melting point of 102°–104°C.

Fructose is soluble in water. A monosaccharide, it occurs naturally in many fruits and vegetables, such as apples and tomatoes, and in honey (approximately 50 percent) and is a constituent of oligosaccharides and polysaccharides. The phosphates of fructose, such as fructose-l,6-diphosphate and fructose-6-phosphate, are intermediate compounds in the dark phase of photosynthesis (Calvin cycle), in major metabolic processes (glycolysis, alcoholic fermentation), and in the biosynthesis of carbohydrates.

Fructose is a valuable food product and is easily assimilated by the organism. It is obtained from fruits by the hydrolysis of saccharose and inulin, as well as by the action of alkalies on D-glucose. In addition to the furanose (natural) form, the open ketone form and other tautomeric forms of fructose are known. Fructose is used in the food-processing industry and in medicine. Fructose-1,6-diphosphate is a drug administered to persons suffering from shock or various heart conditions.


C6H12O5 The commonest of ketoses and the sweetest of sugars, found in the free state in fruit juices, honey, and nectar of plant glands. Also known asD-fructopyranose.


a white crystalline water-soluble sugar occurring in honey and many fruits. Formula: C6H12O6
References in periodicals archive ?
Molecular analysis of the aldolase B gene in patients with hereditary fructose intolerance from Spain.
The spectrum of aldolase B (ALDOB) mutations and the prevalence of hereditary fructose intolerance in Central Europe.
1A are the IEF transferrin profiles for alcohol abuse (lane 6, double bands attributable to a polymorphism in the protein part of transferrin), for galactosemia (lane 5), and for fructose intolerance (lane 4).
Inhibition of phosphomannose isomerase by fructose-l-phosphate: an explanation for defective N-glycosylation in hereditary fructose intolerance.
Our diagnostic strategy for hereditary fructose intolerance is specific to our population but can be transposed and adapted to other populations in which different mutant alleles of aldolase B contribute to the burden of disease.
Corn sugar has been known to be an allowed ingredient for individuals with hereditary fructose intolerance or fructose malabsorption, who have been advised to avoid ingredients that contain fructose," Michael M.
Fructose intolerance in IBS and utility of fructose-restricted diet.

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