Sugar alcohol
Encyclopedia
A sugar alcohol is a hydrogenated
form of carbohydrate
, whose carbonyl group (aldehyde
or ketone
, reducing sugar
) has been reduced to a primary or secondary hydroxyl group (hence the alcohol). Sugar alcohols have the general formula H(HCHO)n+1H, whereas sugars have H(HCHO)nHCO. In commercial foodstuffs sugar alcohols are commonly used in place of table sugar (sucrose
), often in combination with high intensity artificial sweeteners to counter the low sweetness. Of these, xylitol
is perhaps the most popular due to its similarity to sucrose in visual appearance and sweetness. Sugar alcohols do not contribute to tooth decay.
Some common sugar alcohols:
Both disaccharide
s and monosaccharide
s can form sugar alcohols; however, sugar alcohols derived from disaccharide
s (e.g. maltitol and lactitol) are not entirely hydrogenated because only one aldehyde group is available for reduction.
The simplest sugar alcohol, ethylene glycol
, is the sweet, but notoriously toxic, chemical used in antifreeze
. The higher sugar alcohols are for the most part nontoxic.
As a group, sugar alcohols are not as sweet as sucrose
, and they have less food energy
than sucrose. Their flavor is like sucrose, and they can be used to mask the unpleasant aftertaste
s of some high intensity sweeteners
. Sugar alcohols are not metabolized by oral bacteria, and so they do not contribute to tooth decay. They do not brown or caramelize when heated.
In addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy
or chewing gum
. This happens, for example, with the crystalline phase of sorbitol
, erythritol
, xylitol
, mannitol
, lactitol
and maltitol
. The cooling sensation is due to the dissolving of the sugar alcohol being an endothermic (heat-absorbing) reaction, one with a strong heat of solution
.
Sugar alcohols are usually incompletely absorbed into the blood stream from the small intestine
s which generally results in a smaller change in blood glucose than "regular" sugar (sucrose
). This property makes them popular sweeteners among diabetic
s and people on low-carbohydrate diet
s. However, like many other incompletely digestible substances, overconsumption of sugar alcohols can lead to bloating
, diarrhea
and flatulence
because they are not absorbed in the small intestine. Some individuals experience such symptoms even in a single-serving quantity. With continued use, most people develop a degree of tolerance to sugar alcohols and no longer experience these symptoms. As an exception, erythritol
is actually absorbed in the small intestine and excreted unchanged through urine, so it has no side effects at typical levels of consumption.
The table above presents the relative sweetness and food energy
of the most widely-used sugar alcohols. Despite the variance in food energy content of sugar alcohols, EU
labeling requirements assign a blanket value of 2.4 kcal/g to all sugar alcohols.
People who have undergone gastric bypass surgery
, specifically Roux-en-Y (RGB), should be careful not to eat too many sugar alcohols as doing so, with the exception of erythritol, can lead to "dumping"
.
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
form of carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
, whose carbonyl group (aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
or ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...
, reducing sugar
Reducing sugar
A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerisation. This functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's test.-Chemistry:...
) has been reduced to a primary or secondary hydroxyl group (hence the alcohol). Sugar alcohols have the general formula H(HCHO)n+1H, whereas sugars have H(HCHO)nHCO. In commercial foodstuffs sugar alcohols are commonly used in place of table sugar (sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
), often in combination with high intensity artificial sweeteners to counter the low sweetness. Of these, xylitol
Xylitol
Xylitol is a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibers of many fruits and vegetables, and can be extracted from various berries, oats, and mushrooms, as well as fibrous material such as corn husks and sugar cane bagasse, and birch...
is perhaps the most popular due to its similarity to sucrose in visual appearance and sweetness. Sugar alcohols do not contribute to tooth decay.
Some common sugar alcohols:
- GlycolEthylene glycolEthylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
(2-carbon) - GlycerolGlycerolGlycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
(3-carbon) - ErythritolErythritolErythritol is a sugar alcohol that has been approved for use as a food additive in the United States and throughout much of the world. It was discovered in 1848 by British chemist John Stenhouse. It occurs naturally in some fruits and fermented foods...
(4-carbon) - ThreitolThreitolThreitol is a four-carbon sugar alcohol with the molecular formula C4H10O4. It is primarily used as an intermediate in the chemical synthesis of other compounds. It is the diastereomer of Erythritol.-See also:* Erythritol, the diastereomer of threitol...
(4-carbon)
- ArabitolArabitolArabitol or arabinitol is a sugar alcohol. It can be formed by the reduction of either arabinose or lyxose. Some organic acid tests check for the presence of D-arabinitol, which may indicate overgrowth of intestinal parasites such as Candida albicans or other yeast/fungus species....
(5-carbon) - XylitolXylitolXylitol is a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibers of many fruits and vegetables, and can be extracted from various berries, oats, and mushrooms, as well as fibrous material such as corn husks and sugar cane bagasse, and birch...
(5-carbon) - RibitolRibitolRibitol or adonitol is a crystalline pentose alcohol formed by the reduction of ribose. It occurs naturally in the plant Adonis vernalis, as well as in the cell walls of Gram positive bacteria . It also contributes to the chemical structure of riboflavin.-External links:**...
(5-carbon)
- MannitolMannitolMannitol is a white, crystalline organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator...
(6-carbon) - SorbitolSorbitolSorbitol, also known as glucitol, Sorbogem® and Sorbo®, is a sugar alcohol that the human body metabolizes slowly. It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group. Sorbitol is found in apples, pears, peaches, and prunes...
(6-carbon) - DulcitolDulcitolGalactitol is a sugar alcohol, the reduction product of galactose. In people with galactokinase deficiency, a form of galactosemia, excess dulcitol forms in the lens of the eye leading to cataracts....
(6-carbon) - IditolIditolIditol is a sugar alcohol which accumulates in galactokinase deficiency....
(6-carbon)
- IsomaltIsomaltIsomalt is a sugar substitute, a type of sugar alcohol, used primarily for its sugar-like physical properties. It has only a small impact on blood sugar levels and does not promote tooth decay. It has 2 kilocalories/g, half the calories of sugars...
(12-carbon) - MaltitolMaltitolMaltitol is a sugar alcohol used as a sugar substitute. It has 75-90% of the sweetness of sucrose and nearly identical properties, except for browning. It is used to replace table sugar because it has fewer calories, does not promote tooth decay, and has a somewhat lesser effect on blood glucose...
(12-carbon) - LactitolLactitolLactitol is a sugar alcohol used as a replacement bulk sweetener for low calorie foods with approximately 40% of the sweetness of sugar. Lactitol is produced by two manufacturers, Danisco and Purac Biochem.-Applications:...
(12-carbon) - Polyglycitol
Both disaccharide
Disaccharide
A disaccharide or biose is the carbohydrate formed when two monosaccharides undergo a condensation reaction which involves the elimination of a small molecule, such as water, from the functional groups only. Like monosaccharides, disaccharides form an aqueous solution when dissolved in water...
s and monosaccharide
Monosaccharide
Monosaccharides are the most basic units of biologically important carbohydrates. They are the simplest form of sugar and are usually colorless, water-soluble, crystalline solids. Some monosaccharides have a sweet taste. Examples of monosaccharides include glucose , fructose , galactose, xylose...
s can form sugar alcohols; however, sugar alcohols derived from disaccharide
Disaccharide
A disaccharide or biose is the carbohydrate formed when two monosaccharides undergo a condensation reaction which involves the elimination of a small molecule, such as water, from the functional groups only. Like monosaccharides, disaccharides form an aqueous solution when dissolved in water...
s (e.g. maltitol and lactitol) are not entirely hydrogenated because only one aldehyde group is available for reduction.
The simplest sugar alcohol, ethylene glycol
Ethylene glycol
Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
, is the sweet, but notoriously toxic, chemical used in antifreeze
Antifreeze
Antifreeze is a freeze preventive used in internal combustion engines and other heat transfer applications, such as HVAC chillers and solar water heaters....
. The higher sugar alcohols are for the most part nontoxic.
Sugar alcohols as food additives
| Name | Sweetness relative to sucrose | Food energy Food energy Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules... (kcal/g) |
Sweetness per food energy, relative to sucrose |
|---|---|---|---|
| Arabitol Arabitol Arabitol or arabinitol is a sugar alcohol. It can be formed by the reduction of either arabinose or lyxose. Some organic acid tests check for the presence of D-arabinitol, which may indicate overgrowth of intestinal parasites such as Candida albicans or other yeast/fungus species.... |
0.7 | 0.2 | 14 |
| Erythritol Erythritol Erythritol is a sugar alcohol that has been approved for use as a food additive in the United States and throughout much of the world. It was discovered in 1848 by British chemist John Stenhouse. It occurs naturally in some fruits and fermented foods... |
0.812 | 0.213 | 15 |
| Glycerol Glycerol Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids... |
0.6 | 4.3 | 0.56 |
| HSH Hydrogenated starch hydrosylate Hydrogenated starch hydrosylate is a mixture of several sugar alcohols . Hydrogenated starch hydrolysates were developed by a Swedish company in the 1960s. In the United States, hydrogenated starch hydrolysates are provided by three manufacturers. The HSH family of polyols is an approved food... |
0.4–0.9 | 3.0 | 0.52–1.2 |
| Isomalt Isomalt Isomalt is a sugar substitute, a type of sugar alcohol, used primarily for its sugar-like physical properties. It has only a small impact on blood sugar levels and does not promote tooth decay. It has 2 kilocalories/g, half the calories of sugars... |
0.5 | 2.0 | 1.0 |
| Lactitol Lactitol Lactitol is a sugar alcohol used as a replacement bulk sweetener for low calorie foods with approximately 40% of the sweetness of sugar. Lactitol is produced by two manufacturers, Danisco and Purac Biochem.-Applications:... |
0.4 | 2.0 | 0.8 |
| Maltitol Maltitol Maltitol is a sugar alcohol used as a sugar substitute. It has 75-90% of the sweetness of sucrose and nearly identical properties, except for browning. It is used to replace table sugar because it has fewer calories, does not promote tooth decay, and has a somewhat lesser effect on blood glucose... |
0.9 | 2.1 | 1.7 |
| Mannitol Mannitol Mannitol is a white, crystalline organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator... |
0.5 | 1.6 | 1.2 |
| Sorbitol Sorbitol Sorbitol, also known as glucitol, Sorbogem® and Sorbo®, is a sugar alcohol that the human body metabolizes slowly. It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group. Sorbitol is found in apples, pears, peaches, and prunes... |
0.6 | 2.6 | 0.92 |
| Xylitol Xylitol Xylitol is a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibers of many fruits and vegetables, and can be extracted from various berries, oats, and mushrooms, as well as fibrous material such as corn husks and sugar cane bagasse, and birch... |
1.0 | 2.4 | 1.6 |
| Compare with: Sucrose Sucrose Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula... |
1.0 | 4.0 | 1.0 |
As a group, sugar alcohols are not as sweet as sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
, and they have less food energy
Food energy
Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules...
than sucrose. Their flavor is like sucrose, and they can be used to mask the unpleasant aftertaste
Aftertaste
Aftertaste is the taste intensity of a food or beverage that is perceived immediately after that food or beverage is removed from the mouth. The aftertastes of different foods and beverages can vary by intensity and over time, but the unifying feature of aftertaste is that it is perceived after a...
s of some high intensity sweeteners
Sugar substitute
A sugar substitute is a food additive that duplicates the effect of sugar in taste, usually with less food energy. Some sugar substitutes are natural and some are synthetic. Those that are not natural are, in general, called artificial sweeteners....
. Sugar alcohols are not metabolized by oral bacteria, and so they do not contribute to tooth decay. They do not brown or caramelize when heated.
In addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy
Candy
Candy, specifically sugar candy, is a confection made from a concentrated solution of sugar in water, to which flavorings and colorants are added...
or chewing gum
Chewing gum
Chewing gum is a type of gum traditionally made of chicle, a natural latex product, or synthetic rubber known as polyisobutylene. For economical and quality reasons, many modern chewing gums use rubber instead of chicle...
. This happens, for example, with the crystalline phase of sorbitol
Sorbitol
Sorbitol, also known as glucitol, Sorbogem® and Sorbo®, is a sugar alcohol that the human body metabolizes slowly. It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group. Sorbitol is found in apples, pears, peaches, and prunes...
, erythritol
Erythritol
Erythritol is a sugar alcohol that has been approved for use as a food additive in the United States and throughout much of the world. It was discovered in 1848 by British chemist John Stenhouse. It occurs naturally in some fruits and fermented foods...
, xylitol
Xylitol
Xylitol is a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibers of many fruits and vegetables, and can be extracted from various berries, oats, and mushrooms, as well as fibrous material such as corn husks and sugar cane bagasse, and birch...
, mannitol
Mannitol
Mannitol is a white, crystalline organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator...
, lactitol
Lactitol
Lactitol is a sugar alcohol used as a replacement bulk sweetener for low calorie foods with approximately 40% of the sweetness of sugar. Lactitol is produced by two manufacturers, Danisco and Purac Biochem.-Applications:...
and maltitol
Maltitol
Maltitol is a sugar alcohol used as a sugar substitute. It has 75-90% of the sweetness of sucrose and nearly identical properties, except for browning. It is used to replace table sugar because it has fewer calories, does not promote tooth decay, and has a somewhat lesser effect on blood glucose...
. The cooling sensation is due to the dissolving of the sugar alcohol being an endothermic (heat-absorbing) reaction, one with a strong heat of solution
Enthalpy change of solution
The enthalpy of solution, enthalpy of dissolution, or heat of solution is the enthalpy change associated with the dissolution of a substance in a solvent at constant pressure resulting in infinite dilution....
.
Sugar alcohols are usually incompletely absorbed into the blood stream from the small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
s which generally results in a smaller change in blood glucose than "regular" sugar (sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
). This property makes them popular sweeteners among diabetic
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
s and people on low-carbohydrate diet
Low-carbohydrate diet
Low-carbohydrate diets or low-carb diets are dietary programs that restrict carbohydrate consumption usually for weight control or for the treatment of obesity. Foods high in digestible carbohydrates are limited or replaced with foods containing a higher percentage of proteins and fats...
s. However, like many other incompletely digestible substances, overconsumption of sugar alcohols can lead to bloating
Bloating
Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by increased borborygmus or more seriously the total lack of borborygmus.-Symptoms:The most common...
, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
and flatulence
Flatulence
Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestion process of mammals and other animals. The medical term for the mixture of gases is flatus, informally known as a fart, or simply gas...
because they are not absorbed in the small intestine. Some individuals experience such symptoms even in a single-serving quantity. With continued use, most people develop a degree of tolerance to sugar alcohols and no longer experience these symptoms. As an exception, erythritol
Erythritol
Erythritol is a sugar alcohol that has been approved for use as a food additive in the United States and throughout much of the world. It was discovered in 1848 by British chemist John Stenhouse. It occurs naturally in some fruits and fermented foods...
is actually absorbed in the small intestine and excreted unchanged through urine, so it has no side effects at typical levels of consumption.
The table above presents the relative sweetness and food energy
Food energy
Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules...
of the most widely-used sugar alcohols. Despite the variance in food energy content of sugar alcohols, EU
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
labeling requirements assign a blanket value of 2.4 kcal/g to all sugar alcohols.
People who have undergone gastric bypass surgery
Gastric bypass surgery
Gastric bypass procedures are any of a group of similar operations that first divides the stomach into a small upper pouch and a much larger lower "remnant" pouch and then re-arranges the small intestine to allow both pouches to stay connected to it. Surgeons have developed several different ways...
, specifically Roux-en-Y (RGB), should be careful not to eat too many sugar alcohols as doing so, with the exception of erythritol, can lead to "dumping"
Gastric dumping syndrome
Gastric dumping syndrome, or rapid gastric emptying is a condition where ingested foods bypass the stomach too rapidly and enter the small intestine largely undigested. It happens when the upper end of the small intestine, the duodenum, expands too quickly due to the presence of hyperosmolar food...
.
External links
- Alcohol Fact Sheet - An International Food Information CouncilInternational Food Information Council- Background and mission :Founded in 1985, the International Food Information Council is a nonprofit organization whose mission is to effectively communicate science-based information on food safety and nutrition to health and nutrition professionals, educators, government officials, journalists,...
publication