The Details on Xylitol

Xylitol was first discovered in 1891 but didn’t became popular as an alternative sweetener until WWII’s sugar shortages. Since then, we’ve learned that it occurs naturally in small amounts in some foods such as strawberry, raspberry, banana, cauliflower, spinach, mushroom, onion, eggplant, and lettuce.¹ Our bodies also produce xylitol, up to 15 grams per day during normal glucose metabolism.²  Xylitol has about half the calories of regular table sugar but is almost equal in sweetness.³ Of the xylitol we ingest, we absorb only about 50%.⁴ Once absorbed, xylitol is metabolized mainly by the liver.  The xylitol that isn’t absorbed moves into the large intestine where it draws water to the bowel.⁵ Xylitol that reaches the large intestine can also be fermented by gut bacteria to produce short chain fatty acids (SCFAs), therefore acting as a prebiotic.^{6 7} In scientific terms, the molecular structure of xylitol makes it a sugar alcohol, but it is neither a sugar nor an alcohol.

Xylitol’s Sweet Benefits

Cavity Prevention:

Xylitol is best researched and well-known for its beneficial effects on oral health. Of course, when it is used to replace sugar, a known cavity-causing agent, this has a beneficial effect, but xylitol goes beyond a mere sugar replacement. Streptococcus mutans (S. mutans) bacteria, which build plaque as well as cause cavities and tooth decay, take up xylitol but cannot metabolize it, which impedes their growth. Compared to other sugars, xylitol also reduces the growth of plaque and decreases the number of S. mutans in both the plaque and saliva.^{8 9 10} Along with creating a less-acidic environment, xylitol makes S.mutans less adhesive and weaker—actually changing the metabolic status of the bacteria in the mouth.¹¹ All this without negatively affecting mouth bacteria known to be beneficial.¹²

Research on xylitol’s dental benefits began in the 1970s and has found that both short- and longterm use of xylitol in children and adults results in fewer cavities, and fewer decayed, missing, or filled tooth surfaces—all measures of dental health. A 2024 review of 15 studies found that xylitol gum prevented cavities in children better than placebo or no gum.¹³ A 2022 meta-analysis of 30 studies, estimates that xylitol use reduces the risk of cavities by 17%.¹⁴

Ear and Sinus Infection Protection:

Similarly to how xylitol helps prevent cavities, it also appears to prevent ear and sinus infections. Xylitol interferes with the adhesion and metabolism of the bacteria that cause ear and sinus infections; in vitro xylitol stimulates macrophages to produce nitric oxide (a broad spectrum antimicrobial molecule) and it inhibits the formation of biofilms in the oronasal cavity.^{15 16} Acute otitis media (middle ear infection) in children is common, but some studies have found that regular xylitol use leads to fewer infections and fewer antibiotic prescriptions.^{17 18 19} A systematic review of 4 trials found that xylitol was generally well accepted as a preventative for otitis media when given five times a day for a total of 10g of xylitol daily.²⁰ In the studies xylitol was administered via gum, lozenge, or syrup, with gum being most consistently effective. 

Xylitol as a nasal rinse appears to improve sinus symptoms in people with chronic rhinosinusitis^{21 22 23} It was also more effective than saline at reducing nasal symptoms when used after sinus surgery in patients with allergic sensitization.²⁴

Blood Sugar Stability:

Xylitol has long been used in products intended for diabetic patients because it doesn’t cause the abrupt blood sugar and insulin rises and falls that occur with sugar. There is some research to suggest xylitol may influence gut hormones related to hunger and satiety in beneficial ways, and it is known to slow stomach emptying.²⁵ This helps prevent sugar and carbohydrate cravings, helps you to feel full longer, and provides a slow and steady energy release.

Bone Health:

Research is suggesting that xylitol may have a role in bone health. Several animal studies have found that xylitol protects against bone loss related to ovariectomy (a model of menopause) and aging.^{26 27 28  29} The scientists speculate that xylitol's bone density-enhancing properties are due to its ability to promote intestinal absorption of calcium; however, further research is needed.^{30 31}

How to Use Xylitol

In its crystalline form, xylitol (which can be found in the sweetener section of many grocery stores) can be substituted, teaspoon-for-teaspoon, for regular sugar in most cooking, baking, and beverage applications. The exception is bread-making, since xylitol will not feed yeast. There are also some food products and drinks on the market that contain xylitol. Gum, mints, and toothpaste sweetened with xylitol are easy, convenient, and breath-freshening ways to utilize its cavity-preventing properties, while xylitol-based nasal sprays can be used for ear- and sinus- infection protection. 

To promote optimal dental health, xylitol should be used three to five times a day after meals for a total dose of 5-10 grams per day. Chewing xylitol-sweetened gum appears to be most consistently beneficial in the research, possibly because chewing also increases salivary secretions.³²

Is Xylitol Safe?

Xylitol has been safely used for the past 80 years. It is recognized as safe by the FDA and the Joint WHO/FAO Expert Committee on Food Additives. Because xylitol, like all sugar alcohols, is not fully absorbed and consequently draws water to the large intestine, it can have a laxative effect. Because of this, the most commonly reported side effect is diarrhea, but gas, bloating, nausea, and tummy rumblings are also reported. These effects are completely reversed once the xylitol is removed and can be mitigated by introducing xylitol slowly, starting with small amounts and working your way up over time, since the bowel is capable of adjusting to the increased xylitol load. Another good practice is to divide your daily xylitol intake up into smaller doses spread throughout the day and to enjoy it with or directly after food.

Xylitol and the other sugar alcohols are polyols, which are the P in the FODMAP acronym. For anyone following a low FODMAP diet, xylitol should be avoided, and it may not be appropriate for people with IBS. 

A 2024 study linking xylitol to adverse cardiovascular effects made headlines, but a closer look reveals that the study doesn’t tell us much about the effects of ingested xylitol on the cardiovascular system. The study, published in the European Heart Journal, reported that higher circulating levels of xylitol are linked with greater cardiovascular risk, including heart attack, stroke, and death.³³ The cohort in this study had a very high burden of cardiovascular risk factors such as obesity, diabetes, and high blood pressure. One of the major flaws of the study was that the researchers did not account for dietary xylitol intake, so we don’t know if the elevated blood xylitol levels were due to xylitol consumption or endogenous production. The researchers themselves state that the high levels are likely due to endogenous production and not food intake. It is known that the pathway through which xylitol is produced in the body is the same pathway that glucose and fructose are metabolized through, which may indicate that elevated xylitol levels are a biomarker of diets high in sugar or conditions that impair blood sugar metabolism—a likely possibility in this cohort.³⁴

The authors of the study went on to test xylitol in vitro, in mice, and in 10 healthy subjects, yet their results still don’t prove any causation of cardiovascular risk by xylitol ingestion. At best this study shows a correlation between endogenously produced xylitol and cardiovascular risk without proving any causality. While it garnered a lot of attention, this study does not change the safety assessment of xylitol.

The human body is not made to take in excessive amounts of any sweet food. Just because something is natural or may offer some health benefits, does not mean balance and moderation should be thrown out the window. Always keep in mind that it is important to keep sweet indulgences to a minimum, no matter the source. And remember that a healthy diet, along with other lifestyle choices, plays a major role in dental health and in the body’s ability to fight infection in the first place.

Xylitol is NOT Safe for Pets!

While xylitol is perfectly safe for humans it should never be given to animals or pets. It can cause a life-threatening drop in blood sugar or liver damage. Dogs, rabbits, and ferrets are pets of particular concern, but goats, pigs, baboons, and cows are also known to be susceptible. It only takes a small amount, 0.1 gram per kilogram of body weight, for dogs to have a severe reaction, so even a single piece of xylitol gum in a small dog can have disastrous effects.³⁵ The effect also happens quickly, anywhere from 10 minutes to 12 hours after ingestion, so if you know or suspect your pet has ingested any product containing xylitol, seek help immediately from a veterinarian.³⁶

References

1. Vmai, D., Kayalvizhi, R., Kumare, V., & Jacob, S. (2022). Xylitol: bioproduction and applications – a review. Frontiers in Sustainability, 3. https://doi.org/10.3389/frsus.2022.826190
2. Patra, F., Patel, A., & Shah, N. (2017). Microbial production of low-calorie sugars. In Holban, A.M. & Grumezescu A.M. (Eds.), Microbial Production of Food Ingredients and Additives (pp. 259-290). Academic Press.https://doi.org/10.1016/B978-0-12-811520-6.00016-7
3. Vmai, D., Kayalvizhi, R., Kumare, V., & Jacob, S. (2022). Xylitol: bioproduction and applications – a review. Frontiers in Sustainability, 3. https://doi.org/10.3389/frsus.2022.826190
4. Bordier, V., Teysseire, F., Senner, F., Schlotterbeck, G., Drewe, J., Beglinger, C., Wölnerhanssen, B. K., & Meyer-Gerspach, A. C. (2022). Absorption and metabolism of the natural sweeteners erythritol and xylitol in humans: a Dose-Ranging study. International Journal of Molecular Sciences, 23(17), 9867. https://doi.org/10.3390/ijms23179867
5. Mäkinen K. K. (2016). 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. https://doi.org/10.1155/2016/5967907
6. Xiang, S., Ye, K., Li, M., Ying, J., Wang, H., Han, J., Shi, L., Xiao, J., Shen, Y., Feng, X., Bao, X., Zheng, Y., Ge, Y., Zhang, Y., Liu, C., Chen, J., Chen, Y., Tian, S., & Zhu, X. (2021). Xylitol enhances synthesis of propionate in the colon via cross-feeding of gut microbiota. Microbiome, 9(1). https://doi.org/10.1186/s40168-021-01029-6
7. Sato, T., Kusuhara, S., Yokoi, W., Ito, M., & Miyazaki, K. (2017). Prebiotic potential of L-sorbose and xylitol in promoting the growth and metabolic activity of specific butyrate-producing bacteria in human fecal culture. FEMS microbiology ecology, 93(1), fiw227. https://doi.org/10.1093/femsec/fiw227
8. Maguire, A. & Rugg-Gunn, A.J. (2003). Xylitol and caries prevention—it is a magic bullet? British Dental Journal, 194(8), 429-436.https://doi.org/10.1038/sj.bdj.4810022
9. Trahan, L., Xylitol: a review of its action on mutans streptococci and dental plaque--its clinical significance. Int Dent J, 1995. 45(1 Suppl 1): p. 77-92.
10. Krupa, N. C., Thippeswamy, H. M., & Chandrashekar, B. R. (2022). Antimicrobial efficacy of Xylitol, Probiotic and Chlorhexidine mouth rinses among children and elderly population at high risk for dental caries - A Randomized Controlled Trial. Journal of preventive medicine and hygiene, 63(2), E282–E287. https://doi.org/10.15167/2421-4248/jpmh2022.63.2.1772
11. Livesey, G. (2003). Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties. Nutrition Research Reviews, 16(2), 163-191. https://doi.org/10.1079/NRR200371 
12. Bahador, A., Lesan, S., & Kashi, N. (2012). Effect of xylitol on cariogenic and beneficial oral streptococci: a randomized, double-blind crossover trial. Iranian journal of microbiology, 4(2), 75–81. 
13. Ramasubbu, D., & Duane, B. (2024). Do chewing gums and sweets containing xylitol prevent caries in children?. Evidence-based dentistry, 25(2), 89–90. https://doi.org/10.1038/s41432-024-01018-2
14. ALHumaid, J., & Bamashmous, M. (2022). Meta-analysis on the Effectiveness of Xylitol in Caries Prevention. Journal of International Society of Preventive & Community Dentistry, 12(2), 133–138. https://doi.org/10.4103/jispcd.JISPCD_164_21
15. Silva, C. F. F. S. D., Silva, F. E. R. D., Pauna, H. F., Hurtado, J. G. G. M., & Dos Santos, M. C. J. (2022). Symptom assessment after nasal irrigation with xylitol in the postoperative period of endonasal endoscopic surgery. Brazilian journal of otorhinolaryngology, 88(2), 243–250. https://doi.org/10.1016/j.bjorl.2020.05.023
16. Ferreira, A. S., de Souza, M. A., Barbosa, N. R., & da Silva, S. S. (2008). Leishmania amazonensis: xylitol as inhibitor of macrophage infection and stimulator of macrophage nitric oxide production. Experimental parasitology, 119(1), 74–79. https://doi.org/10.1016/j.exppara.2007.12.012
17. Margulis, I., Cohen-Kerem, R., Stein, N., Roitman, A., Cohen-Vaizer, M., Fridman, E., & Gordin, A. (2024). Xylitol nasal spray for prevention of recurrent acute otitis media in children: A prospective two-center cohort study. International journal of pediatric otorhinolaryngology, 176, 111818. https://doi.org/10.1016/j.ijporl.2023.111818
18. Uhari, M., T. Tapiainen, and T. Kontiokari, Xylitol in preventing acute otitis media. Vaccine, 2000. 19 Suppl 1: p.  S144-7.
19. Uhari, M., Kontiokari, T., Koskela, M., & Niemelä, M. (1996). Xylitol chewing gum in prevention of acute otitis media: double blind randomised trial. BMJ (Clinical research ed.), 313(7066), 1180–1184. https://doi.org/10.1136/bmj.313.7066.1180
20. Danhauer, J. L., Johnson, C. E., Corbin, N. E., & Bruccheri, K. G. (2010). Xylitol as a prophylaxis for acute otitis media: systematic review. International journal of audiology, 49(10), 754–761. https://doi.org/10.3109/14992027.2010.493897
21. Lin, L., Tang, X., Wei, J., Dai, F., & Sun, G. (2017). Xylitol nasal irrigation in the treatment of chronic rhinosinusitis. American journal of otolaryngology, 38(4), 383–389. https://doi.org/10.1016/j.amjoto.2017.03.006
22. Weissman, J. D., Fernandez, F., & Hwang, P. H. (2011). Xylitol nasal irrigation in the management of chronic rhinosinusitis: a pilot study. The Laryngoscope, 121(11), 2468–2472. https://doi.org/10.1002/lary.22176
23. Caetano, J. V. B., Valera, F. C. P., Anselmo-Lima, W. T., & Tamashiro, E. (2024). Non-antibiotic antimicrobial agents for chronic rhinosinusitis: a narrative review. Brazilian journal of otorhinolaryngology, 90(4), 101436. https://doi.org/10.1016/j.bjorl.2024.101436
24. Kim, D. H., Kim, Y., Lim, I. G., Cho, J. H., Park, Y. J., Kim, S. W., & Kim, S. W. (2019). Effect of Postoperative Xylitol Nasal Irrigation on Patients with Sinonasal Diseases. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 160(3), 550–555. https://doi.org/10.1177/0194599818802815
25. Wölnerhanssen, B. K., Meyer-Gerspach, A. C., Beglinger, C., & Islam, M. S. (2020). Metabolic effects of the natural sweeteners xylitol and erythritol: A comprehensive review. Critical reviews in food science and nutrition, 60(12), 1986–1998. https://doi.org/10.1080/10408398.2019.1623757
26. Mattila, P. T., Svanberg, M. J., Pökkä, P., & Knuuttila, M. L. (1998). Dietary xylitol protects against weakening of bone biomechanical properties in ovariectomized rats. The Journal of nutrition, 128(10), 1811–1814. https://doi.org/10.1093/jn/128.10.1811
27. Mattila, P. T., Svanberg, M. J., Jämsä, T., & Knuuttila, M. L. (2002). Improved bone biomechanical properties in xylitol-fed aged rats. Metabolism: clinical and experimental, 51(1), 92–96. https://doi.org/10.1053/meta.2002.28105
28. Svanberg, M., & Knuuttila, M. (1994). Dietary xylitol prevents ovariectomy induced changes of bone inorganic fraction in rats. Bone and mineral, 26(1), 81–88. https://doi.org/10.1016/s0169-6009(08)80164-x
29. Mattila P, Svanberg, M, Knuttila, M. Increased bone volume and bone mineral content in xylitol-fed aged rats. Gerontology 2001;47:300-305.
30. Tamura, M., Hoshi, C., & Hori, S. (2013). Xylitol affects the intestinal microbiota and metabolism of daidzein in adult male mice. International journal of molecular sciences, 14(12), 23993–24007. https://doi.org/10.3390/ijms141223993
31. Brommage, R., Binacua, C., Antille, S., & Carrié, A. L. (1993). Intestinal calcium absorption in rats is stimulated by dietary lactulose and other resistant sugars. The Journal of nutrition, 123(12), 2186–2194. https://doi.org/10.1093/jn/123.12.2186
32. ALHumaid, J., & Bamashmous, M. (2022). Meta-analysis on the Effectiveness of Xylitol in Caries Prevention. Journal of International Society of Preventive & Community Dentistry, 12(2), 133–138. https://doi.org/10.4103/jispcd.JISPCD_164_21
33. Witkowski, M., Nemet, I., Li, X. S., Wilcox, J., Ferrell, M., Alamri, H., Gupta, N., Wang, Z., Tang, W. H. W., & Hazen, S. L. (2024). Xylitol is prothrombotic and associated with cardiovascular risk. European heart journal, 45(27), 2439–2452. https://doi.org/10.1093/eurheartj/ehae244
34. Attia, P., & Attia, P. (2024b, June 21). Does xylitol increase risk of cardiovascular disease? Peter Attia. https://peterattiamd.com/xylitol-and-cvd/
35. Gunnars, K. (2024, July 17). Xylitol: everything you need to know. Healthline. https://www.healthline.com/nutrition/xylitol-101#toxic-to-dogs
36. Xylitol Pet Safety. (n.d.). NowFoods.com. Retrieved August 20, 2024, from https://www.nowfoods.com/healthy-living/articles/xylitol-pet-safety