Xylitol

Xylitol is a chemical compound with the formula C
5
H
12
O
5
, or HO(CH2)(CHOH)3(CH2)OH; specifically, one particular stereoisomer with that structural formula. It is a colorless or white crystalline solid that is soluble in water. It can be classified as a polyalcohol and a sugar alcohol, specifically an alditol. The name derives from Ancient Greek: ξύλον, xyl[on], "wood", with the suffix -itol used to denote sugar alcohols.

Xylitol[1]
Xylitol
Xylitol crystals.jpg
Xylitol crystals
Names
Pronunciation /ˈzlɪtɒl/
IUPAC name
meso-Xylitol
Preferred IUPAC name
(2R,3R,4S)-Pentane-1,2,3,4,5-pentol
Other names
(2R,3R,4S)-Pentane-1,2,3,4,5-pentaol (not recommended)
1,2,3,4,5-Pentahydroxypentane
Xylite
Identifiers
  • 87-99-0 checkY
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.001.626 Edit this at Wikidata
E number E967 (glazing agents, ...)
UNII
  • InChI=1S/C5H12O5/c6-1-3(8)5(10)4(9)2-7/h3-10H,1-2H2/t3-,4+,5+ checkY
    Key: HEBKCHPVOIAQTA-SCDXWVJYSA-N checkY
  • OC[C@@H](O)[C@H](O)[C@@H](O)CO
Properties
C5H12O5
Molar mass 152.146 g·mol−1
Density 1.52 g/cm3
Melting point 92 to 96 °C (198 to 205 °F; 365 to 369 K)
Boiling point 345.39 °C (653.70 °F; 618.54 K) Predicted value using Adapted Stein & Brown method[2]
~100 g/L
Hazards
NFPA 704 (fire diamond)
1
1
0
Related compounds
Related alkanes
Pentane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references

Xylitol is used as a food additive and sugar substitute. Its European Union code number is E967.[3] Replacing sugar with xylitol in food products may promote better dental health, but evidence is lacking on whether xylitol itself prevents dental cavities.[4]

HistoryEdit

Sugar rationing during World War II led to an interest in sugar substitutes. Interest in xylitol and other polyols became intense, leading to their characterization and manufacturing methods.[5][6]

Structure, production, commerceEdit

Xylitol occurs naturally in small amounts in plums, strawberries, cauliflower, and pumpkin; humans and many other animals make trace amounts during metabolism of carbohydrates.[5] Unlike most sugar alcohols, xylitol is achiral.[7] Most other isomers of pentane-1,2,3,4,5-pentol are chiral, but xylitol has a plane of symmetry.

Industrial production starts with lignocellulosic biomass from which xylan is extracted; raw biomass materials include hardwoods, softwoods, and agricultural waste from processing maize, wheat, or rice. The xylan polymers can be hydrolyzed into xylose, which is catalytically hydrogenated into xylitol. The conversion changes the sugar (xylose, an aldehyde) into the primary alcohol, xylitol. Impurities are then removed.[5]

The processing is often done using standard industrial methods; industrial fermentation involving bacteria, fungi, or yeast, especially Candida tropicalis, are common, but are not as efficient.[5][8]

According to the US Department of Energy, xylitol production by fermentation from discarded biomass is one of the most valuable renewable chemicals for commerce, forecast to be a US$1.4 billion industry by 2025.[9]

UsesEdit

Xylitol is used as a sugar substitute in such manufactured products as drugs, dietary supplements, confections, toothpaste, and chewing gum, but is not a common household sweetener.[4][10] Xylitol has negligible effects on blood sugar because it is metabolized independently of insulin.[10] It is approved as a food additive in the United States.[11]

Xylitol is also found as an additive to saline solution for nasal irrigation and has been reported to be effective in improving symptoms of chronic sinusitis.[12]

Food propertiesEdit

Nutrition, taste, and cookingEdit

Humans absorb xylitol more slowly than sucrose, and xylitol supplies 40% fewer calories than an equal mass of sucrose.[10]

Xylitol has about the same sweetness as sucrose,[10] but is sweeter than similar compounds like sorbitol and mannitol.[5]

Xylitol is stable enough to be used in baking,[13] but because xylitol and other polyols are heat stable, they do not caramelise as sugars do. When used in foods, they lower the freezing point of the mixture.[14]

Food risksEdit

No serious health risk exists in most humans for normal levels of consumption; The European Food Safety Authority has not set a limit on daily intake of xylitol. Due to the adverse laxative effect that all polyols have on the digestive system in high doses, xylitol is banned from soft drinks in the European Union. Similarly due to a 1985 report, by the E.U. Scientific Committee on Food, stating that "ingesting 50 g a day of xylitol can cause diarrhea", tabletop sweeteners containing xylitol are required to display the warning: "Excessive consumption may induce laxative effects".[15]

MetabolismEdit

Xylitol has 2.4 kilocalories of food energy per gram of xylitol (10 kilojoules per gram) according to U.S. and E.U. food-labeling regulations.[16][3] The real value can vary, depending on metabolic factors.[17]

Primarily, the liver metabolizes absorbed xylitol. The main metabolic route in humans occurs in cytoplasm, via nonspecific NAD-dependent dehydrogenase (polyol dehydrogenase), which transforms xylitol to D-xylulose. Specific xylulokinase phosphorylates it to D-xylulose-5-phosphate. This then goes to pentose phosphate pathway for further processing.[17]

About 50% of eaten xylitol is absorbed via the intestines. Of the remaining 50% that is not absorbed by the intestines, in humans, 50–75% of the xylitol remaining in the gut is fermented by gut bacteria into short-chain organic acids and gases, which may produce flatulence. The remnant unabsorbed xylitol that escapes fermentation is excreted unchanged, mostly in feces; less than 2 g of xylitol out of every 100 g ingested is excreted via urine.[17]

Xylitol ingestion also increases motilin secretion, which may be related to xylitol's ability to cause diarrhea.[18] The non-digestible but fermentable nature of xylitol also contributes to constipation relieving effects.[19]

Health effectsEdit

Dental careEdit

Research has identified carbohydrates, oral bacteria, tooth anatomy, along with their time of interaction as the main pathobiological etiology for dental caries. Sucrose is deemed to be the most cariogenic carbohydrate consumed by humans, as it is a substrate to various oral bacteria to produce insoluble polysaccharides and acid.[20] Streptococcus mutans is a major pathological bacteria. It uses carbohydrates via glycolysis to adhere to tooth surfaces with an extracellular matrix, and produces an acidic environment; that acid dissolves the outer tooth enamel layer of the teeth it adheres to.[21]

Xylitol, a sugar alcohol containing 5 carbon-polyol is metabolized via the phospho-enolpyruvate-phospho-transferase pathway (PEP-PTS) in S. mutans, which produces xylitol-5-phosphate as a product.[22] Xylitol-5-phosphate competes with phosphofructokinase and therefore, results in inhibition of glycolysis via accumulation of glucose-6-phosphate.[22] Over long periods of time of xylitol use, S. mutans are observed to alter their enzymatic activity.[23]

Burt (2006) conducted a systematic review looking at the effect of sugar alcohols on caries activity.[24] His systematic review included randomized controlled trials (RCT) as well as observational studies.[24] Burt concluded that Xylitol displayed non-cariogenic properties in all protocols tested.[24] Interestingly, he also concluded that mothers chewing xylitol-containing gums effectively inhibited the transmission of S. mutans to their offspring.[24] Nayak et al. (2014) also conducted a review where they showed the positive effects of Xylitol in gummy bears, syrups, mouthrinse, dentifrice on inhibiting dental caries.[25] Lastly, Chan et al. (2020) concluded that xylitol has inhibitory effects on S. mutans and Candida albicans.[26] However, other studies, such as one by Muhlemann et al. (1977) seem to call for more research in this area as the results were inconclusive.[27] A Cochrane review conducted in 2015 included 10 studies which displayed a low quality evidence on the effectiveness of xylitol containing fluoride toothpastes when compared to fluoride only toothpaste.[28]

Ear achesEdit

In 2011, EFSA "concluded that there was not enough evidence to support" the claim that xylitol-sweetened gum could prevent middle-ear infections with a fast onset, which is also known as acute otitis media (AOM).[15][29] A 2016 review indicated that xylitol in chewing gum or a syrup may have a moderate effect in preventing AOM in healthy children.[30] It may be an alternative to conventional therapies (such as antibiotics) to lower risk of ear aches in healthy children – reducing risk of occurrence by 25%[31] – although there is no definitive proof that it could be used as a therapy for ear aches.[30]

DiabetesEdit

In 2011, EFSA approved a marketing claim that foods or beverages containing xylitol or similar sugar replacers cause lower blood glucose and lower insulin responses compared to sugar-containing foods or drinks.[13][32] Xylitol products are used as sucrose substitutes for weight control,[13][19] as xylitol has 40 percent fewer calories than sucrose (2.4 kcal/g compared to 4.0 kcal/g for sucrose).[13][33] The glycemic index (GI) of xylitol is only 7% of the GI for glucose.[34]

Adverse effectsEdit

HumansEdit

When ingested at high doses, xylitol and other polyols may cause gastrointestinal discomfort, including flatulence, diarrhea, and irritable bowel syndrome (see Metabolism above); some people experience the adverse effects at lower doses.[15][35] Xylitol has a lower laxation threshold than some sugar alcohols but is more easily tolerated than mannitol and sorbitol.[36]

Increased xylitol consumption can increase oxalate, calcium, and phosphate excretion to urine (termed oxaluria, calciuria, and phosphaturia, respectively). These are known risk factors for kidney stone disease, but despite that, xylitol has not been linked to kidney disease in humans.[37]

Dogs and other animalsEdit

Xylitol poisons dogs.[38] Ingesting 100 milligrams of xylitol per kilogram of body weight (mg/kg bw) causes dogs to experience a dose-dependent insulin release; depending on the dose it can result in life-threatening hypoglycemia. Hypoglycemic symptoms of xylitol toxicity may arise as quickly as 30 to 60 minutes after ingestion. Vomiting is a common first symptom, which can be followed by tiredness and ataxia. At doses above 500 mg/kg bw, liver failure is likely and may result in coagulopathies like disseminated intravascular coagulation.[39]

Xylitol is safe for cats,[40] rhesus macaques, horses, and rats.[39] Cats can tolerate ingesting xylitol doses of 1000 mg/kg bw.[40]

See alsoEdit

ReferencesEdit

  1. ^ Safety data sheet for xylitol from Fisher Scientific. Retrieved 2014-11-02.
  2. ^ "Xylitol". Chemspider.com. Chemical Structure. Retrieved 13 May 2015.
  3. ^ a b "Food legislation". polyols-eu.org. European Association of Polyol Producers. Retrieved 7 February 2019.
  4. ^ a b Riley, P.; Moore, D.; Ahmed, F.; Sharif, M.O.; Worthington, H.V. (26 March 2015). "Xylitol-containing products for preventing dental caries in children and adults". The Cochrane Database of Systematic Reviews (3): CD010743. doi:10.1002/14651858.CD010743.pub2. PMID 25809586.
    Riley, P.; Moore, D.; Ahmed, F.; Sharif, M. O.; Worthington, H. V. (2015). "Can xylitol – used in products like sweets, candy, chewing gum, and toothpaste – help prevent tooth decay in children and adults?". The Cochrane Database of Systematic Reviews. Lay summary (3): CD010743. doi:10.1002/14651858.CD010743.pub2. PMID 25809586.  
  5. ^ a b c d e Ur-Rehman, S.; Mushtaq, Z.; Zahoor, T.; Jamil, A.; Murtaza, M.A. (2015). "Xylitol: A review on bio-production, application, health benefits, and related safety issues". Critical Reviews in Food Science and Nutrition. 55 (11): 1514–1528. doi:10.1080/10408398.2012.702288. PMID 24915309. S2CID 20359589.
  6. ^ Hicks, Jesse (Spring 2010). "The pursuit of sweet". Science History. Science History Institute.
  7. ^ Wrolstad, Ronald E. (2012). Food Carbohydrate Chemistry. John Wiley & Sons. p. 176. ISBN 9780813826653. Retrieved 20 October 2012 – via Google Books.
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  9. ^ Felipe Hernández-Pérez, Andrés; de Arruda, Priscila Vaz; Sene, Luciane; da Silva, Silvio Silvério; Kumar Chandel, Anuj; de Almeida Felipe, Maria das Graças (16 July 2019). "Xylitol bioproduction: State-of-the-art, industrial paradigm shift, and opportunities for integrated biorefineries". Critical Reviews in Biotechnology. 39 (7): 924–943. doi:10.1080/07388551.2019.1640658. ISSN 0738-8551. PMID 31311338. S2CID 197421362.
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  11. ^ "Xylitol". United States Code of Federal Regulations. Food Additives Permitted for Direct Addition to Food for Human Consumption, Special Dietary and Nutritional Additives. U.S. Food and Drug Administration. 1 April 2012. CFR Title 21, Part 172, Section 172.395.
  12. ^ Weissman, Joshua D.; Fernandez, Francisca; Hwang, Peter H. (November 2011). "Xylitol nasal irrigation in the management of chronic rhinosinusitis: A pilot study". The Laryngoscope. 121 (11): 2468–2472. doi:10.1002/lary.22176. ISSN 1531-4995. PMID 21994147. S2CID 36572019.
  13. ^ a b c d "Xylitol". Diabetes.co.uk. Retrieved 28 October 2018.
  14. ^ Burgos, Karen; Subramaniam, Persis; Arthur, Jennifer (21 November 2016). "Reformulation guide for small to medium sized companies" (PDF). Leatherhead Food Research – via The Food and Drink Federation.
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  16. ^ "Chapter 3: Energy Conversion Factors". Calculation of the Energy Content of Foods. Food and Agriculture Organization (Report). The United Nations. Retrieved 30 March 2017.
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  18. ^ Wölnerhanssen, B.K.; Meyer-Gerspach, A.C.; Beglinger, C.; Islam, M.S. (June 2019). "Metabolic effects of the natural sweeteners xylitol and erythritol: A comprehensive review". Critical Reviews in Food Science and Nutrition. 60 (12): 1986–1998. doi:10.1080/10408398.2019.1623757. PMID 31204494. S2CID 189944738.
  19. ^ a b Salli, Krista; Lehtinen, Markus J.; Tiihonen, Kirsti; Ouwehand, Arthur C. (6 August 2019). "Xylitol's health benefits beyond dental health: A comprehensive review". Nutrients. 11 (8): 1813. doi:10.3390/nu11081813. ISSN 2072-6643. PMC 6723878. PMID 31390800.
  20. ^ Forssten, Sofia D.; Björklund, Marika; Ouwehand, Arthur C. (2 March 2010). "Streptococcus mutans, caries, and simulation models". Nutrients. 2 (3): 290–298. doi:10.3390/nu2030290. ISSN 2072-6643. PMC 3257652. PMID 22254021.
  21. ^ Berkowitz, R.J.; Turner, J.; Hughes, C. (1984). "Microbial characteristics of the human dental caries associated with prolonged bottle-feeding". Archives of Oral Biology. 29 (11): 949–951. doi:10.1016/0003-9969(84)90097-9. ISSN 0003-9969. PMID 6596042.
  22. ^ a b Assev, Synnöve; Rölla, Gunnar (15 August 2009). "Further Studies on the Growth Inhibition of Streptococcus Mutans OMZ 176 by Xylitol". Acta Pathologica et Microbiologica Scandinavica, Section B. 94B (1–6): 97–102. doi:10.1111/j.1699-0463.1986.tb03026.x. PMID 3728029.
  23. ^ Lee, Young-Eun; Choi, Youn-Hee; Jeong, Seong-Hwa; Kim, Hee-Sook; Lee, Sung-Hee; Song, Keun-Bae (16 December 2008). "Morphological changes in Streptococcus mutans after chewing gum containing xylitol for twelve months". Current Microbiology. 58 (4): 332–337. doi:10.1007/s00284-008-9332-4. ISSN 0343-8651. PMID 19085034. S2CID 6520956.
  24. ^ a b c d Burt, Brian A. (February 2006). "The use of sorbitol- and xylitol-sweetened chewing gum in caries control". The Journal of the American Dental Association. 137 (2): 190–196. doi:10.14219/jada.archive.2006.0144. ISSN 0002-8177. PMID 16521385.
  25. ^ Nayak, Prathibha Anand; Nayak, Ullal Anand; Khandelwal, Vishal (10 November 2014). "The effect of xylitol on dental caries and oral flora". Clinical, Cosmetic and Investigational Dentistry. 2014 (6): 89–94. doi:10.2147/ccide.s55761. ISSN 1179-1357. PMC 4232036. PMID 25422590.
  26. ^ Chan, Ally; Ellepola, Kassapa; Truong, Thuyen; Balan, Preethi; Koo, Hyun; Seneviratne, Chaminda Jayampath (November 2020). "Inhibitory effects of xylitol and sorbitol on Streptococcus mutans and Candida albicans biofilms are repressed by the presence of sucrose". Archives of Oral Biology. 119: 104886. doi:10.1016/j.archoralbio.2020.104886. ISSN 0003-9969. PMID 32932149. S2CID 221746172.
  27. ^ Mühlemann, H.R.; Schmid, R.; Noguchi, T.; Imfeld, T.; Hirsch, R.S. (1977). "Some dental effects of xylitol under laboratory and in vivo conditions". Caries Research. 11 (5): 263–276. doi:10.1159/000260278. ISSN 1421-976X. PMID 18284.
  28. ^ Riley, Philip; Moore, Deborah; Ahmed, Farooq; Sharif, Mohammad O.; Worthington, Helen V. (26 March 2015). "Xylitol-containing products for preventing dental caries in children and adults". Cochrane Database of Systematic Reviews (3): CD010743. doi:10.1002/14651858.cd010743.pub2. ISSN 1465-1858. PMID 25809586.
  29. ^ EFSA pannel (June 2011). "Scientific opinion on the substantiation of health claims related to sugar-free chewing gum sweetened with xylitol and plaque acid neutralisation (ID 485), maintenance of tooth mineralisation (ID 486, 562, 1181), reduction of dental plaque (ID 485, 3085)". EFSA Journal. 9 (6): 2266. doi:10.2903/j.efsa.2011.2266.
  30. ^ a b Azarpazhooh, A.; Lawrence, H.P.; Shah, P.S. (3 August 2016). "Xylitol for preventing acute otitis media in children up to 12 years of age". The Cochrane Database of Systematic Reviews (8): CD007095. doi:10.1002/14651858.CD007095.pub3. PMID 27486835.
  31. ^ Marom, Tal; Marchisio, Paola; Tamir, Sharon Ovnat; Torretta, Sara; Gavriel, Haim; Esposito, Susanna (12 February 2016). "Complementary and alternative medicine treatment options for otitis media". Medicine. 95 (6): e2695. doi:10.1097/MD.0000000000002695. ISSN 0025-7974. PMC 4753897. PMID 26871802.
  32. ^ EFSA panel (April 2011). "Scientific opinion on the substantiation of health claims related to the sugar replacers xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt, erythritol, D-tagatose, isomaltulose, sucralose and polydextrose and maintenance of tooth mineralisation by decreasing tooth demineralisation, and reduction of post-prandial glycaemic responses". EFSA Journal. 9 (4): 2076. doi:10.2903/j.efsa.2011.2076.
  33. ^ Tiefenbacher, Karl F. (2017). "Technology of Main Ingredients – Sweeteners and Lipids". Wafer and Waffle. Elsevier. pp. 123–225. doi:10.1016/b978-0-12-809438-9.00003-x. ISBN 978-0-12-809438-9.
  34. ^ Foster-Powell, K.; Holt, S.H.; Brand-Miller, J.C. (July 2002). "International table of glycemic index and glycemic load values: 2002". The American Journal of Clinical Nutrition. 76 (1): 5–56. doi:10.1093/ajcn/76.1.5. PMID 12081815.
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  36. ^ Sugar Alcohols (PDF) (Report). Canadian Diabetes Association. 1 May 2005. Archived from the original (PDF) on 25 April 2012. Retrieved 14 March 2012.
  37. ^ Janket, S.; Benwait, J.; Isaac, P.; Ackerson, L.K.; Meurman, J.H. (2019). "Oral and systemic effects of xylitol consumption". Caries Research. 53 (5): 491–501. doi:10.1159/000499194. hdl:10138/305074. PMID 31060040. S2CID 146811298.
  38. ^ "Paws off xylitol; It's dangerous for dogs". US Food and Drug Administration. 7 July 2021. Retrieved 9 September 2021.
  39. ^ a b Schmid, R.D.; Hovda, L.R. (2016). "Acute hepatic failure in a dog after xylitol ingestion". Journal of Medical Toxicology. 12 (2): 201–205. doi:10.1007/s13181-015-0531-7. PMC 4880608. PMID 26691320.
  40. ^ a b Jerzsele, A.; et al. (2018). "Effects of p.o. administered xylitol in cats". Journal of Veterinary Pharmacology and Therapeutics. 41 (3): 409–414. doi:10.1111/jvp.12479. PMID 29430681.

External linksEdit