xylose

Xylitol[1]
IUPAC name	(2R,3R,4S)-Pentane-1,2,3,4,5-pentol
Other names	1,2,3,4,5-Pentahydroxypentane; Xylite
Identifiers
CAS number	87-99-0 Y
Properties
Molecular formula	C5H12O5
Molar mass	152.15 g/mol
Density	1.52 g/cm³
Melting point	92-96 °C
Boiling point	216 °C
Related compounds
Related alkanes	Pentane
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Xylitol crystals

Xylitol (from Greek ξύλον - xyl[on], "wood" + suffix -itol, used to denote sugar alcohols) is a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibres of many fruits and vegetables, including various berries, corn husks, oats, and mushrooms.^[2] It can be extracted from corn fibre,^[3] birch, raspberries, plums, and corn. Xylitol is roughly as sweet as sucrose with only two-thirds the food energy. As with most sugar alcohols, initial consumption can result in bloating, diarrhea, and flatulence, although generally rather less so than other sugar alcohols like sorbitol.

Xylitol is an organic compound with the formula (CHOH)₃(CH₂OH)₂. This achiral species is one of four isomers of 1,2,3,4,5-pentapentanol.

Production of xylitol

Xylitol (Finnish ksylitoli) was first derived from birch trees in Finland in the 20th century and was first popularised in Europe as a safe sweetener for people with diabetes that would not impact insulin levels. Today, using hardwood or maize sources, the largest manufacturer globally is the Danish company Danisco, with several other suppliers from China.^[4][5] Xylitol is produced by hydrogenation of xylose, which converts the sugar (an aldehyde) into a primary alcohol.

Properties

One teaspoon (5 gm) of xylitol contains 9.6 calories, as compared to one teaspoon of sugar, which has 15 calories. Xylitol has virtually no aftertaste, and is advertised as "safe for diabetics and individuals with hyperglycemia." This tolerance is attributed to the lower impact of xylitol on a person's blood sugar, compared to that of regular sugars.^[6]

Dietary use worldwide

Xylitol is widely used in Finland, its "home country." Many Finnish confectioneries employ xylitol, or have a xylitol version available. Virtually all chewing gum sold in Finland is sweetened with xylitol.^[7]

Medical applications

Dental care

Xylitol is a "tooth friendly" non-fermentable sugar alcohol.^[8][9] A systematic review study^[10] on the efficacy of xylitol has indicated dental health benefits in caries prevention, showing superior performance to other polyols (poly-alcohols). Early studies from Finland in the 1970s found that a group chewing sucrose gum had 2.92 decayed, missing, or filled (dmf) teeth compared to 1.04 in the group chewing xylitol gums.^[11] In another study, researchers had mothers chew xylitol gum 3 months after delivery until their children were 2 years old. The researchers found that children in the xylitol group had "a 70% reduction in cavities (dmf)."^[11] Recent research^[12] confirms a plaque-reducing effect and suggests that the compound, having some chemical properties similar to sucrose, attracts and then "starves" harmful micro-organisms, allowing the mouth to remineralise damaged teeth with less interruption. (However, this same effect also interferes with yeast micro-organisms and others, so xylitol is inappropriate for making yeast-based bread, for instance.)

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.^[13]

A recent study demonstrated that as a water additive for animals, xylitol was effective in reducing plaque and calculus accumulation in cats.^[14]

Diabetes

Possessing approximately 40% less food energy,^[15] xylitol is a low-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.

Osteoporosis

Xylitol also has potential as a treatment for osteoporosis. A group of Finnish researchers has found that dietary xylitol prevents weakening of bones in laboratory rats, and actually improves bone density.^[16][17]

Ear and upper respiratory infections

Studies have shown that xylitol chewing gum can help prevent ear infections^[18] (acute otitis media); the act of chewing and swallowing assists with the disposal of earwax and clearing the middle ear, whilst the presence of xylitol prevents the growth of bacteria in the eustachian tubes (auditory tubes or pharyngotympanic tubes) which connect the nose and ear.^[19] When bacteria enter the body they hold on to the tissues by hanging on to 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.^[20] 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 (naturally present in the body) antimicrobial factors.^[21]

Infection

In rats, xylitol has been found to increase the activity of neutrophils, the white blood cells involved in fighting many bacteria. This effect seems to be quite broad, acting even in cases such as general sepsis.^[22]

Candida yeast

A recent report suggests that consumption of xylitol may help control oral infections of Candida yeast; in contrast, galactose, glucose, and sucrose may increase proliferation.^[23]

Benefits for pregnant or nursing women

Xylitol is not only safe for pregnant and nursing women, but studies show that regular use significantly reduces the probability of transmitting the Streptococcus mutans bacteria, which is responsible for tooth decay, from mother to child during the first two years of life by as much as 80%.^[24]

Safety

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.^[25] Like most sugar alcohols, it has a laxative effect because sugar alcohols are not fully broken down during digestion; albeit ten times weaker than sorbitol. The effect depends upon the individual. In one study of 13 children, 4 experienced diarrhea when consuming over 65 grams per day.^[26] Studies have reported that adaptation occurs after several weeks of consumption.^[26]

Dogs that have ingested foods containing high levels of xylitol (greater than 100 milligram of xylitol consumed per kilogram of bodyweight) have presented with low blood sugar (hypoglycemia) which can be life-threatening.^[27] Low blood sugar can result in a loss of coordination, depression, collapse and seizures in as soon as 30 minutes.^[28][29] Intake of very high doses of xylitol (greater than 500 – 1000 mg/kg bwt) has also been implicated in liver failure in dogs, which can be fatal.^[30] These are points of controversy, however, as earlier World Health Organization studies using much higher doses on dogs for long periods showed no ill effect.^[31]

See also

• Other sugar alcohols: mannitol, sorbitol, erythritol, maltitol, lactitol
• Herbal sweetener: stevia
• Artificial sweeteners: aspartame, sucralose
• L-xylulose reductase
• Mouthwash
• Xylonic acid

Notes & References

1. ^ MSDS for xylitol
2. ^ Gare, Fran (February 1, 2003). The Sweet Miracle of Xylitol. Basic Health Publications, Inc.. ISBN 1-59120-038-5. http://books.google.com/books?id=5tgZG6Sb2aAC. 
3. ^ R Sreenivas Rao, Ch. Pavanajyothi, RS Prakasham, PN Sharma, L Venkateswar Rao (2006) Xylitol production from corn fibre and sugarcane bagasse hydrolysates by Candida tropicalis Bioresource Technology 97:1974-1978.
4. ^ http://www.whatsnewiningredients.com/Food-Ingredients/Articles.aspx/18767
5. ^ http://www.ap-foodtechnology.com/Formulation/Danisco-ramps-up-xylitol-production-in-China-new-deal
6. ^ Sugar Substitutes: Are They Safe? - HealtHints Newsletter
7. ^ Advanced food development and functional foods from Finland
8. ^ Edwardsson S, Birkhed D, Mejare B., "Acid production from Lycasin, maltitol, sorbitol and xylitol by oral streptococci and lactobacilli", Acta Odontol Scand 1977; 35: 257–263 
9. ^ Drucker D, Verran J., "Comparative effects of the substance-sweeteners glucose, sorbitol, sucrose, xylitol and trichlorosucrose on lowering of pH by two oral Streptococcus mutans strains in vitro.", Arch Oral Biol 1980; 24: 965–970 
10. ^ A Maguire & A J Rugg-Gunn, "Xylitol and caries prevention--is it a magic bullet?", British Dental Journal (2003) Apr 26;194(8):429-36, http://www.nature.com/bdj/journal/v194/n8/abs/4810022a.html 
11. ^ ^{a b} American Academy of Pediatric Dentistry. (2006) Policy on the Use of Xylitol in Caries Prevention.
12. ^ Tanzer, JM (1995). Xylitol chewing gum and dental caries. International dental journal 45 (1 Suppl 1):65-76. (online abstract)
13. ^ U.S. FDA 21 CFR §101.80
14. ^ Clarke, D.E. (2006) Drinking Water Additive Decreases Plaque and Calculus Accumulation in Cats. J Vet Dent(23)2:79-82
15. ^ www.diabetes.org.nz/food/artificialsweeteners.html
16. ^ Mattila PT, Svanberg MJ, Jämsä T, Knuuttila ML (2002). Improved bone biomechanical properties in xylitol-fed aged rats.Metabolism 51(1):92-6. (online abstract)
17. ^ Mattila, PT (1999). Dietary xylitol in the prevention of experimental osteoporosis: Beneficial effects on bone resorption, structure and biomechanics. Dissertation, Institute of Dentistry, University of Oulu. (online)
18. ^ Uhari M, et al. (1998). A novel use of xylitol sugar in preventing acute otitis media. Pediatrics, 102(4): 879–974.
19. ^ Drgreene.com commercial site
20. ^ British Medical Journal
21. ^ 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): 11614–9. doi:10.1073/pnas.97.21.11614. PMID 11027360. 
22. ^ Renko, Marjo; Valkonen P, Tapiainen T, Kontiokari T, Mattila P, Knuuttila M, Svanberg M, Leinonen M, Karttunen R, Uhari M (2008 March 11;8:45.). "Xylitol-supplemented nutrition enhances bacterial killing and prolongs survival of rats in experimental pneumococcal sepsis". BMC Microbiology 8: 45. doi:10.1186/1471-2180-8-45. PMID 18334022. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18334022. Retrieved 2008-08-23. 
23. ^ Abu-Elteen, Khaled H. The influence of dietary carbohydrates on in vitro adherence of four Candida species to human buccal epithelial cells. Microbial Ecology in Health and Disease (2005), 17(3), 156-162
24. ^ Maternal Xylitol Consumption to Prevent Mother-Child Transmission of Mutans Streptococci
25. ^ Mäkinen KK (1976). "Long-term tolerance of healthy human subjects to high amounts of xylitol and fructose: general and biochemical findings". Int Z Vitam Ernahrungsforsch Beih 15: 92–104. PMID 783060. 
26. ^ ^{a b} Wang YM, van Eys J (1981). "Nutritional significance of fructose and sugar alcohols". Annu. Rev. Nutr. 1: 437–75. doi:10.1146/annurev.nu.01.070181.002253. PMID 6821187. 
27. ^ Dunayer, E.K., Gwaltney-Brant, S.M. (2006) Acute hepatic failure and coagulopathy associated with xylitol ingestion in dogs, Journal of the American Veterinary Medical Association (229)7:1113-1117
28. ^ ASPCA article
29. ^ Dunayer, E.K (2004) Hypoglycemia following canine ingestion of xylitol-containing gum, Veterinary and Human Toxicology 46(2):87-88
30. ^ Dunayer, E.K (2006) New findings on the effects of xylitol ingestion in dogs Veterinary Medicine 101(12):791-797
31. ^ [1] Xlear, Inc. Issues Response to JAVMA Report on Dogs and Xylitol