Xylitol

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Xylitol[1]
Xylitol
Xylitol crystals.jpg
Xylitol crystals
Names
Pronunciation /ˈzlɪtɒl/
Systematic 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
3D model (JSmol)
ChEMBL
ECHA InfoCard 100.001.626
E number E967 (glazing agents, ...)
UNII
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
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored 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 ☑Y☒N ?)
Infobox references

Xylitol is a sugar alcohol used as a sugar substitute. The name derives from Ancient Greek: ξύλον, xyl[on], "wood" + suffix -itol, used to denote sugar alcohols. Xylitol is categorized as a polyalcohol or sugar alcohol (specifically an alditol). It has the formula CH2OH(CHOH)3CH2OH. It is a colorless or white solid that is soluble in water. Use of manufactured products containing xylitol may promote better dental health, but evidence is lacking on whether it prevents cavities.[3]

Xylitol has an E number E967 when used as a food additive within EU.[4]

Structure, production, occurrence[edit]

Xylitol is naturally occurring in small amounts in plums, strawberries, cauliflower, and pumpkin; humans and animals make trace amounts during metabolism of carbohydrates.[5] Unlike most sugar alcohols, xylitol is achiral.[6] 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][7]

Uses[edit]

Xylitol is used as a sugar substitute in manufactured products, such as drugs or dietary supplements, confections, toothpaste, and chewing gum, but is not a common household sweetener.[3][8] Xylitol has negligible effects on blood sugar because it is metabolized independently of insulin.[8] Absorbed more slowly than sugar, xylitol supplies 40% fewer calories than table sugar.[8] It is approved as a food additive in the United States.[9]

Food properties[edit]

Xylitol has about the same sweetness as sucrose,[8] but more sweetness than similar compounds like sorbitol and mannitol.[5] It has a glycemic index of 7 (100 for glucose).[10] Because xylitol and other polyols are heat stable, they do not caramelise as sugars do, and they also lower the freezing point of mixtures in which they are used.[11]

No health risk exists for normal levels of consumption, and 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 EU. Similarly due to a 1985 report, by the EU 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".[12] Chewing gum containing xylitol is permitted.[13]

Health effects[edit]

Dental care[edit]

As of 2015, clinical trials examining whether xylitol alone or with other agents can prevent cavities found the evidence was too poor to allow generalizations, although when children with permanent teeth use fluoride toothpaste with xylitol, they may get fewer cavities than when using fluoride toothpaste without it.[3] People apparently get fewer cavities when they chew gum sweetened with xylitol (or similar polyols such as sorbitol) than when they chew gum sweetened with sucrose.[14][15][16]

In 2008, the European Food Safety Authority (EFSA) evaluated the literature on xylitol, concluding, "xylitol chewing gum reduces the risk of cavities in children".[13][17] The claim required rewording because xylitol chewing gum is not a medicine, thus can "not be claimed to reduce the risk of a disease".[13] In 2011, EFSA approved a claim that replacing sugar with xylitol and similar sweeteners "may maintain tooth mineralisation compared with sugar-containing foods."[12][18]

Preventing ear aches[edit]

Based on studies of children in Finland who are in daycare or in school, as of 2016, xylitol, administered in chewing gum or a syrup, may have a moderate effect in preventing ear aches in healthy children; whether it can help prevent ear infections in children who are prone to them or who have a respiratory infection is unclear.[19] The EFSA evaluated the claim in 2011, and "concluded that there was not enough evidence to support" the claim that xylitol-sweetened gum could prevent ear aches.[12][20]

Diabetes management[edit]

In 2011, the 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.[18][21]

Weight management[edit]

Eating processed foods containing xylitol as a non-nutritive sweetener instead of sugar may be useful to help manage body weight.[21]

Adverse effects[edit]

Humans[edit]

Xylitol has no known toxicity in humans.[12] At high doses, xylitol and other polyols cause gastrointestinal discomfort, including flatulence, diarrhea, and irritable bowel syndrome; some people have these adverse effects at lower doses.[12][22] Xylitol has a lower laxation threshold than some sugar alcohols but is more easily tolerated than mannitol and sorbitol.[23]

Dogs[edit]

In dogs, xylitol (in amounts greater than 100 mg/kg of body weight) generates a rapid, dose-dependent insulin release that can result in hypoglycemia, which can be life-threatening.[24][25] Low blood sugar can result in a loss of coordination, depression, collapse, and seizures in dogs as quickly as 30 minutes following ingestion.[26] Intake of doses of xylitol greater than 500 to 1000 mg per kilogram body weight has been implicated in potentially fatal liver failure in dogs.[27]

Xylitol is used in comparatively much smaller doses, in the ingredients of two commercial veterinary drinking-water additives, marketed to prevent plaque and freshen the breath of pets.[28][29]

Metabolism[edit]

Xylitol has 2.4 kcal/g (10 kJ/mol) of food energy according to US and EU food labeling regulations.[30][4] Real value varies a bit from this due to many metabolic factors. About 50% of eaten xylitol is not absorbed by the intestines in humans. Instead, 50–75% of this amount is fermented by gut bacteria to short-chain organic acids and gases, which may cause flatulence. The rest of the unabsorbed xylitol is excreted unchanged mostly in feces and less than 2 g of xylitol out of every 100 g ingested is excreted in urine.[31]

About 50% of xylitol is absorbed via intestines. Primarily, the liver metabolizes it. The main metabolic route in humans is: in cytoplasm, nonspecific NAD-dependent dehydrogenase (polyol dehydrogenase) transforms xylitol to D-xylulose. Specific xylulokinase phosphorylates it to D-xylulose-5-phosphate. This then goes to pentose phosphate pathway for further processing.[31]

History[edit]

Sugar rationing during World War II led to an interest in sugar substitutes when interest in xylitol and other polyols became intense, leading to their characterization and manufacturing methods.[5][32]

See also[edit]

References[edit]

  1. ^ Safety data sheet for xylitol from Fisher Scientific. Retrieved 2014-11-02.
  2. ^ "Xylitol". Chemspider. Retrieved 2015-05-13.
  3. ^ a b c Riley, P; Moore, D; Ahmed, F; Sharif, MO; Worthington, HV (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. Lay summary. open access
  4. ^ a b "Food – EPA – European Association of Polyol Producers". polyols-eu.org. Retrieved 2019-02-07.
  5. ^ a b c d e Ur-Rehman, S; Mushtaq, Z; Zahoor, T; Jamil, A; Murtaza, MA (2015). "Xylitol: a review on bioproduction, application, health benefits, and related safety issues". Critical Reviews in Food Science and Nutrition. 55 (11): 1514–28. doi:10.1080/10408398.2012.702288. PMID 24915309.
  6. ^ Wrolstad, Ronald E. (2012). Food Carbohydrate Chemistry. John Wiley & Sons. p. 176. ISBN 9780813826653. Retrieved 2012-10-20.
  7. ^ Jain, H; Mulay, S (March 2014). "A review on different modes and methods for yielding a pentose sugar: xylitol". International Journal of Food Sciences and Nutrition. 65 (2): 135–43. doi:10.3109/09637486.2013.845651. PMID 24160912.
  8. ^ a b c d "Xylitol". Drugs.com. 2018. Retrieved 12 October 2018.
  9. ^ "Xylitol; from Part 172, Food Additives Permitted for Direct Addition to Food for Human Consumption, Special Dietary and Nutritional Additives; Sec. 172.395". Code of Federal Regulations Title 21. United States Food and Drug Administration. 2012-04-01.
  10. ^ Foster-Powell, K; Holt, SH; Brand-Miller, JC (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.
  11. ^ 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.
  12. ^ a b c d e "Is xylitol good for your teeth?". NHS Eat well. 13 April 2016. Retrieved 28 October 2018.
  13. ^ a b c "Xylitol chewing gum/pastilles and reduction of the risk of tooth decay – Scientific substantiation of a health claim related to xylitol chewing gum/pastilles and reduction the risk of tooth decay". EFSA Journal. 6 (11): 852. November 2008. doi:10.2903/j.efsa.2008.852. open access
  14. ^ "Policy on the use of xylitol in caries prevention" (PDF). Reference Manual. 33 (6): 42–44. 2010. Retrieved 2012-03-14.
  15. ^ Mickenautsch, Steffen; Yengopal, Veerasamy (2012). "Effect of xylitol versus sorbitol: A quantitative systematic review of clinical trials". International Dental Journal. 62 (4): 175–188. doi:10.1111/j.1875-595X.2011.00113.x. PMID 23016999.
  16. ^ 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.
  17. ^ Söderling, E (April 2009). "Controversies around Xylitol". European Journal of Dentistry. 3 (2): 81–2. PMC 2676064. PMID 19421385.
  18. ^ a b "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. April 2011. doi:10.2903/j.efsa.2011.2076. open access
  19. ^ Azarpazhooh, A; Lawrence, HP; Shah, PS (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. open access
  20. ^ "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. June 2011. doi:10.2903/j.efsa.2011.2266. open access
  21. ^ a b "Xylitol – Benefits on Plaque and Saliva and Safety". Diabetes.co.uk. Retrieved 28 October 2018.
  22. ^ Mäkinen, Kauko (2016-10-20). "Gastrointestinal Disturbances Associated with the Consumption of Sugar Alcohols with Special Consideration of Xylitol: Scientific Review and Instructions for Dentists and Other Health-Care Professionals". International Journal of Dentistry. 2016: 5967907. doi:10.1155/2016/5967907. PMC 5093271. PMID 27840639.
  23. ^ "Sugar Alcohols" (PDF). Canadian Diabetes Association. 2005-05-01. Archived from the original (PDF) on 2012-04-25. Retrieved 2012-03-14.
  24. ^ Gwaltney-Brant, Sharon M. "Xylitol - Toxicology". Merck Veterinary Manual. Retrieved 28 October 2018.
  25. ^ Dunayer, Eric K.; Gwaltney-Brant, Sharon M. (2006). "Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs". Journal of the American Veterinary Medical Association. 229 (7): 1113–1117. doi:10.2460/javma.229.7.1113. PMID 17014359.
  26. ^ Dunayer, Eric K. (2004). "Hypoglycemia following canine ingestion of xylitol-containing gum". Veterinary and Human Toxicology. 46 (2): 87–88. PMID 15080212.
  27. ^ Dunayer, Eric K. (2006). "New findings on the effects of xylitol ingestion in dogs" (PDF). Veterinary Medicine. 101 (12): 791–797. Archived from the original (PDF) on 2013-06-17. Retrieved 2012-03-14.
  28. ^ C.E.T Aquadent. Drugs.com
  29. ^ BreathaLyser Plus (Canada). Drugs.com
  30. ^ "Chapter 3: Calculation Of The Energy Content Of Foods – Energy Conversion Factors". Food and Agriculture Organization of the United Nations. Retrieved 30 March 2017.
  31. ^ a b Livesey, G. (2003). "Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties". Nutrition Research Reviews. 16 (2): 163–191. doi:10.1079/NRR200371. ISSN 1475-2700.
  32. ^ Hicks, Jesse (Spring 2010). "The Pursuit of Sweet". Science History Institute.

External links[edit]

  • Media related to Xylitol at Wikimedia Commons