Xylitol

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Xylitol[1]

Xylitol crystals
IUPAC name

(2R,4S)-Pentane-1,2,3,4,5-pentol
Other names

1,2,3,4,5-Pentahydroxypentane;
Xylite
Identifiers
CAS number 87-99-0 YesY
PubChem 6912
ChemSpider 6646 N
UNII VCQ006KQ1E YesY
ChEMBL CHEMBL96783 N
Jmol-3D images Image 1
Properties
Molecular formula C5H12O5
Molar mass 152.15 g mol−1
Density 1.52 g/cm³
Melting point

92–96 °C
Boiling point

216 °C
Solubility in water ~ 1.5 g/mL
Hazards
NFPA 704
NFPA 704.svg
0
1
0
Related compounds
Related alkanes Pentane
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Xylitol (pron.: /ˈzaɪlɪtɒl/; Greek: ξύλον, xyl[on], "wood" + suffix -itol, used to denote sugar alcohols), categorized as a polyalcohol (alditol), has interesting applications in hygiene and nutraceutical formulations and products. Xylitol has the formula (CHOH)3(CH2OH)2 and is an achiral[2] isomer of pentane-1,2,3,4,5-pentol. Xylitol could function as a diabetic sweetener which is roughly as sweet as sucrose with 33% fewer calories. Unlike other natural or synthetic sweeteners, xylitol is actively beneficial for dental health by reducing caries to a third in regular use and tooth remineralization, and also has been shown to reduce the incidence of acute middle ear infection.

Xylitol is naturally found in low concentrations 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,[3][4] and birch.[5] However, industrial production starts from xylan (a hemicellulose) extracted from hardwoods or corncobs, which is hydrolyzed into xylose and catalytically hydrogenated into xylitol.

Contents

Production [edit]

Xylitol was discovered almost simultaneously by German and French chemists in the late 19th century,[6] and was first popularized in Europe as a safe sweetener for people with diabetes that would not affect insulin levels. Its dental significance was researched in Finland in the early 1970s, when scientists at Turku University showed it had significant dental benefits.[6] Those became known as the "Turku sugar studies". Today, using hardwood or maize sources, the largest manufacturer globally is the Danish company Danisco, with several other suppliers from China.[7] Xylitol is produced by hydrogenation of xylose, which converts the sugar (an aldehyde) into a primary alcohol.

Properties [edit]

One gram of xylitol contains 2.4 kilocalories (kcal),[8] as compared to one gram of sugar, which has 3.87 kcal.[9] Xylitol has virtually no aftertaste, and is advertised as "safe for diabetics and individuals with hyperglycemia." This tolerance is attributed to the lower effect of xylitol on a person's blood sugar, compared to that of regular sugars as it has a very low glycemic index of 7 (glucose has a GI of 100).[10]

Medical applications [edit]

Dental care [edit]

Xylitol is a “tooth-friendly”, nonfermentable sugar alcohol.[11][12] It appears to have more dental health benefits than other polyalcohols.[13] The structure of xylitol contains a tridentate ligand, (H-C-OH)3 that can rearrange with polyvalent cations like Ca2+. This interaction allows for Ca2+ to be transported through the gut wall barrier and through saliva may remineralize enamel before dental caries form.[14]

Early studies from Finland in the 1970s found compared to chewing sucrose-flavored gum, xylitol resulted in nearly two fewer cavities or missing teeth.[15] Cavity-causing bacteria prefer six-carbon sugars or disaccharides, while xylitol is non-fermentable and can not be used as an energy source, interfering with bacterial growth and reproduction. The harmful micro-organisms are starved in the presence of xylitol, allowing the mouth to remineralize damaged teeth with less interruption. This same property renders it unsuitable for making bread as it interferes with the ability of yeast to digest sugars.[14] At least 6 grams of xylitol per day is thought to be needed for dental efficacy; for most chewing gum or breath mints this would require 12 pieces per day.[14]

Xylitol also inhibits the growth of Streptococcus pneumoniae, as well as the attachment of Haemophilus influenzae on the nasopharyngeal cells.[14]

However, despite these promising conjectures two systematic reviews of clinical trials could not find conclusive evidence that xylitol was indeed superior to other polyols such as sorbitol[16] or equal to that of topical fluoride in its anti-caries effect.[17]

Furthermore, the 33-month Xylitol for Adult Caries Trial in which participants were given either five grams of Xylitol or a placebo, found no statistically or clinically significant reduction in 33-month caries increment among adults at an elevated risk of developing caries. [18]

Xylitol-based products are allowed by the U.S. Food and Drug Administration to make the medical claim that they do not promote dental cavities.[19]

Diabetes [edit]

Possessing approximately 33% fewer calories, xylitol is a lower-calorie alternative to table sugar. Absorbed more slowly than sugar, it does not contribute to high blood sugar levels or the resulting hyperglycemia caused by insufficient insulin response. This characteristic has also proven beneficial for people suffering from metabolic syndrome, a common disorder that includes insulin resistance, hypertension, hypercholesterolemia, and an increased risk for blood clots.[20] Xylitol is used as a sweetener in medicines, chewing gum and pastilles.[21]

Ear and upper respiratory infections [edit]

Studies have shown xylitol chewing gum can help prevent acute otitis media[22] the act of chewing and swallowing assists with the disposal of earwax and clearing the middle ear, while the presence of xylitol prevents the growth of bacteria in the eustachian tubes (auditory or pharyngotympanic tubes) which connect the nose and ear.[23] When bacteria enter the body, they adhere to the tissues using a variety of sugar complexes. The open nature of xylitol and its ability to form many different sugar-like structures appears to interfere with the ability of many bacteria to adhere. In a double-blind, randomized, controlled trial, saline solutions of xylitol significantly reduced the number of nasal coagulase-negative Staphylococcus bacteria. The researchers attributed the benefits to the increased effectiveness of endogenous antimicrobial factors.[24] In a very small case series, nasally administered xylitol reduced ear complaints in children previously having chronic complaints, on the order of almost one a month, by more than 92%. The author also reported beneficial effects on asthma with nasal administration.[25]

Safety [edit]

Xylitol has no known toxicity in humans. In one study, the participants consumed a diet containing a monthly average of 1.5 kg of xylitol with a maximum daily intake of 430 g with no apparent ill effects.[26] Like most sugar alcohols, it has a laxative effect because sugar alcohols are not fully broken down during digestion; albeit one-tenth the strength of sorbitol.[clarification needed] The effect depends upon the individual. In one study of 13 children, four experienced diarrhea when consuming over 65 grams per day.[27] Studies have reported adaptation occurs after several weeks of consumption.[27]

As with other sugar alcohols, with the exception of erythritol, consumption in excess of one's laxation threshold (the amount of sweetener that can be consumed before abdominal discomfort sets in) can result in temporary gastrointestinal side effects, such as bloating, flatulence, and diarrhea. Adaptation, an increase of the laxation threshold, occurs with regular intake. Xylitol has a lower laxation threshold than some sugar alcohols, but is more easily tolerated than others such as mannitol and sorbitol.[27][28]

Dogs [edit]

Dogs that have ingested foods containing xylitol (greater than 100 milligrams of xylitol consumed per kilogram of bodyweight) have presented with low blood sugar (hypoglycemia), which can be life-threatening.[29] Low blood sugar can result in a loss of coordination, depression, collapse and seizures in as little as 30 minutes.[30] Intake of doses of xylitol (greater than 500 – 1000 mg/kg bwt) has been implicated in liver failure in dogs, which can be fatal.[31]

See also [edit]

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Notes and references [edit]

  1. ^ Material safety data sheet for xylitol from Fisher Scientific. Retrieved on 2013-02-23.
  2. ^ Wrolstad, Ronald E. (2012). Food Carbohydrate Chemistry. John Wiley & Sons. p. 176. ISBN 9780813826653. Retrieved October 20, 2012. "Xylitol contains asymmetric carbon atoms, but it is not chiral because the molecule as a whole is symmetrical." 
  3. ^ Gare, Fran (February 1, 2003). The Sweet Miracle of Xylitol. Basic Health Publications, Inc. ISBN 1-59120-038-5. 
  4. ^ Rao, R. Sreenivas; Jyothi, Ch. Pavana; Prakasham, RS; Sharma, PN; Rao, L. Venkateswar (2006). "Xylitol production from corn fiber and sugarcane bagasse hydrolysates by Candida tropicalis". Bioresource Technology 97 (15): 1974–1978. doi:10.1016/j.biortech.2005.08.015. PMID 16242318. Retrieved March 14, 2012. 
  5. ^ "FAQ". Xylitol Canada. Retrieved March 14, 2012. 
  6. ^ a b "Xylitol FAQ's". Xlear. Retrieved March 14, 2012. 
  7. ^ "Danisco ramps up xylitol production in China, new deal". AP Food Technology. March 16, 2005. Archived from the original on July 16, 2011. Retrieved March 14, 2012. 
  8. ^ Walters, D. Eric. "Xylitol". All About Sweeteners. Retrieved March 14, 2012. 
  9. ^ "Sugars, granulated (sucrose)". Self Nutrition Data. Retrieved March 14, 2012.  With a serving size of 100 grams, there are 387 calories.
  10. ^ The American Journal of Clinical Nutrition, January 1, 2002: International table of glycemic index and glycemic load values Retrieved 2012-08-26
  11. ^ Edwardsson, Stig; Birkhed, Dowen; Mejàre, Bertil (1977). "Acid production from Lycasin, maltitol, sorbitol and xylitol by oral streptococci and lactobacilli". Acta Odontologica Scandinavica 35 (5): 257–263. doi:10.3109/00016357709019801. PMID 21508. 
  12. ^ Drucker, D.B.; Verran, J. (1979). "Comparative effects of the substance-sweeteners glucose, sorbitol, sucrose, xylitol and trichlorosucrose on lowering of pH by two oral Streptococcus mutans strains in vitro". Archives of Oral Biology 24 (12): 965–970. doi:10.1016/0003-9969(79)90224-3. PMID 44996. 
  13. ^ Maguire, A; Rugg-Gunn, A J (2003). "Xylitol and caries prevention — is it a magic bullet?". British Dental Journal 194 (8): 429–436. doi:10.1038/sj.bdj.4810022. PMID 12778091. Retrieved March 14, 2012. 
  14. ^ a b c d Remacle, Claude; Reusens, Brigitte, ed. (2004). Functional foods, ageing and degenerative disease. Cambridge, England: Woodhead Publishing. p. 202. ISBN 978-1-85573-725-9. Retrieved March 14, 2012. 
  15. ^ "Policy on the Use of Xylitol in Caries Prevention". Reference Manual (American Academy of Pediatric Dentistry) 33 (6): 42–44. 2010. Retrieved March 14, 2012. 
  16. ^ Mickenautsch, Steffen; Yengopal, Veerasamy (2012). "Effect of xylitol versus sorbitol: A quantitative systematic review of clinical trials". International Dental Journal 62 (4): 175–88. doi:10.1111/j.1875-595X.2011.00113.x. PMID 23016999. 
  17. ^ Mickenautsch, Steffen; Yengopal, Veerasamy (2012). "Anticariogenic effect of xylitol versus fluoride - a quantitative systematic review of clinical trials". International Dental Journal 62 (1): 6–20. doi:10.1111/j.1875-595X.2011.00086.x. PMID 22251032. 
  18. ^ Results from the Xylitol for Adult Caries Trial (X-ACT), The Journal of the American Dental Association January 1, 2013 vol. 144 no. 1 21-30
  19. ^ "§101.80". Code of Federal Regulations Title 21. United States Food and Drug Administration. Retrieved March 14, 2012. 
  20. ^ Martí, N.; Funes, L.L.; Saura, D.; Micol, V. (July 2008). "An update on alternative sweeteners". International sugar journal 110 (1315): 425–429. ISSN 0020-8841. 
  21. ^ Savola, Päivikki. "Xylitol combats cavities". Advanced food development and functional foods from Finland. Finfood - Finnish Food Information. Archived from the original on April 18, 2008. 
  22. ^ Azarpazhooh, A.; Limeback, H.; Lawrence, H. P.; Shah, P. S. (2011). Xylitol for preventing acute otitis media in children up to 12 years of age. In Azarpazhooh, Amir. "Cochrane Database of Systematic Reviews". Cochrane database of systematic reviews (Online) (11): CD007095. doi:10.1002/14651858.CD007095.pub2. PMID 22071833.  edit
  23. ^ Greene, Alan. "Ear Infections and Xylitol". Dr. Greene. Retrieved March 14, 2012. 
  24. ^ Zabner J, Seiler MP, Launspach JL, et al. (October 2000). "The osmolyte xylitol reduces the salt concentration of airway surface liquid and may enhance bacterial killing". Proceedings of the National Academy of Sciences of the United States of America 97 (21): 11614–11619. doi:10.1073/pnas.97.21.11614. PMC 17249. PMID 11027360. Retrieved March 14, 2012. 
  25. ^ Jones, AH (2001). "Intranasal xylitol, recurrent otitis media and asthma: Three case studies". Clinical Practice of Alternative Medicine. 2 (2): 112–17. 
  26. ^ Mäkinen, KK (1976). "Long-term tolerance of healthy human subjects to high amounts of xylitol and fructose: general and biochemical findings". Internationale Zeitschrift fur Vitamin und Ernahrungsforschung Beiheft 15: 92–104. PMID 783060. 
  27. ^ a b c Wang, Yeu-Ming; van Eys, Jan (1981). "Nutritional significance of fructose and sugar alcohols". Annual Review of Nutrition 1: 437–75. doi:10.1146/annurev.nu.01.070181.002253. PMID 6821187. 
  28. ^ "Sugar Alcohols". Canadian Diabetes Association. May 2005. Retrieved March 14, 2012. 
  29. ^ Dunayer, Eric K.; Gwaltney-Brant, Sharon M. (October 2006). "Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs". American Veterinary Medical Association 229 (7): 1113–1117. doi:10.2460/javma.229.7.1113. PMID 17014359. 
  30. ^ Dunayer, Erik K. (April 2004). "Hypoglycemia following canine ingestion of xylitol-containing gum". Veterinary and human toxicology 46 (2): 87–88. PMID 15080212. 
  31. ^ Dunayer, Erik K. (December 2006). "New findings on the effects of xylitol ingestion in dogs". Veterinary Medicine 101 (12): 791–797. Retrieved March 14, 2012. 
E numbers - 950-969
1-carbon
2-carbon
3-carbon
4-carbon
5-carbon
6-carbon
7-carbon
Deoxy sugar alcohols
Cyclic sugar alcohols
Glycylglycitols
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