What is xylitol? Xylitol is one of a group of sugar substitutes known as polyols. Others in the same group include sorbitol and maltitol, which have 6 carbon structures (and can be metabolised by harmful bacteria). However, xylitol has a unique 5 carbon structure which is metabolised only by friendly bacteria. Xylitol is a sweetener that occurs naturally. It can be found in berries and other fruits, some vegetables and in the woody fibres of birch tree bark and corn cobs. It is even produced by the human body as a part of normal metabolism.

Where was xylitol discovered? Xylitol was discovered almost simultaneously by German and French chemists in the late 19th century. In the Soviet Union it has been used for decades as a sweetener for diabetics, and in Germany in solutions for intravenous feeding. In China, xylitol has been used for various medical purposes. It is now used in over 40 countries as a safe, natural and healthy alternative sweetener. It has been approved by FDA in the USA for over 25 years.

How is xylitol manufactured? Xylitol derives its name from xylan, meaning wood, and is manufactured from natural xylan-rich sources (biomass) such as birch tree bark, and corn fibre. Wood sugar (xylose) is extracted from the biomass, and the liquid wood sugar is then converted to pure crystalline xylitol.

How is xylitol metabolised in the body? Dietary xylitol is easily metabolised by the body. A small portion is slowly absorbed through the small intestine and carried in the portal blood supply to the liver, where it is converted to glucose. Because of the slowness of absorption, the majority of xylitol (approximately ¾ of that consumed) moves down to the lower intestine, There it is metabolised by friendly bacteria to short-chain fatty acids, which are mostly returned to the liver for oxidation, providing energy (2).

Is xylitol suitable for diabetics? Xyltiol has a very low glycemic index of 7. Consumption of xylitol has a negligible to nil effect on blood glucose levels and insulin. It has been used for many years in the USA, former USSR, and Europe in the diabetic diet (2-4).

How does xylitol differ from other sweeteners? Xylitol is the only natural sugar substitute that has the same sweetening power and delicious taste of sucrose. It differs from other natural sweeteners such as sorbitol, fructose and glucose because the xylitol molecule has five, instead of six, carbon atoms. This means that it cannot be fermented by harmful mouth bacteria that cause tooth decay (1). Xylitol differs from intense artificial sweeteners including aspartame, acesulfame-K and sucralose in that it has no adverse effects or bitter aftertaste.

Does xylitol have any aftertaste? Xylitol has no aftertaste at all. It has a nearly identical taste to sugar.

How much xylitol do I use in my tea or coffee? Xylitol is spoon for spoon as sweet as sugar in tea or coffee but many of our customers say they use a little less in their hot drinks.

Is xylitol good to use in cooking and baking? Xylitol behaves the same as table sugar in cooking and baking, however sometimes the sweetness has to be adjusted depending on the recipe.

What quantity of xylitol do I use compared to sugar in my recipes? The quantity of xylitol used in recipes depends on each individual’s taste. However, when using xylitol in recipes with white flour use a half cup xylitol to one cup of white sugar. Taste the batter and adjust if not sweet enough. A banana cake is going to need less xylitol than a lemon cake.

What else can I use xylitol in? Xylitol can also be used in custards, sauces, salad dressings, marinades, lemon butter, meringues; in fact it replaces sugar in most recipes. Xylitol will not caramelise. Xylitol is great over porridge and mixed in natural yoghurt for added sweetness.

How does xylitol offer weight loss benefits? Sugar in the diet can cause insulin fluctuations which often creates sugar cravings as insulin levels drop. Xylitol is 7 on the glycemic index (table sugar is 65). The glycemic index or GI measures the ability of a food to raise insulin levels. Xylitol does not increase blood sugar or insulin levels, therefore reducing cravings for sugary foods while allowing a sweet tooth to be satisfied.

Is xylitol suitable for use in low carbohydrate diets? As only about one quarter of consumed xylitol becomes glucose, it is stated to have 75% less carbohydrate than table sugar. Therefore it is suitable for use in a low carbohydrate diet.

What are the differences between xylitol and fructose? They are both nutritive sweeteners, however xylitol is not classed as a sugar like fructose because of its 5-carbon structure (fructose has a 6-carbon structure). The metabolism of xylitol is mostly insulin-independent, whereas that of fructose is not (the GI of xylitol is 7, compared to 23 for fructose). Fructose can be metabolised by harmful bacteria and is as cariogenic as sugar, whereas xylitol cannot be metabolised by harmful bacteria in the mouth and gut because of its 5-carbon structure. Xylitol protects the mouth against plaque and tooth decay, and helps keep the natural flora balance in the gut by allowing friendly bacteria to flourish.

What is the caloric value of xylitol? Xylitol has been analysed in the United States and Europe as having 2.4 kcal per gram, which is 40% less than table sugar.

Is xylitol a good sweetener in sports drinks for active people and athletes? Sports nutrition is going to be a huge new area for xylitol research. Because of xylitol’s low glycemic index and mostly insulin-independent metabolism it is ideal for maintaining steady blood sugar and insulin levels. This may help promote muscle building (anabolism).

What health benefits does xylitol have? Xylitol consumption has a number of health benefits, both dental and medical. Teeth are protected not only because plaque accumulation and tooth decay are diminished (6-10), but because xylitol remineralises and strengthens tooth enamel (11-13). In addition, xylitol helps keep the intestines healthy because friendly bacteria which metabolise xylitol can flourish. In Europe in the 1970’s, xylitol was referred to as “glucose with delay” because of its slow and steady conversion to glucose, without impacting on insulin, and hence its use in parenteral nutrition.

Are there any side effects of xylitol consumption? Clinical studies have demonstrated that xylitol consumption of up to 70 grams per day can be tolerated in diabetic patients, and up to 200 grams per day in adapted normal subjects without side effects. Some sensitive individuals may experience a slight laxative effect with the higher doses. As the enzymes that metabolise xylitol adapt to consumption over time, if this effect occurs it is usually transient (5). In practice, xylitol consumption would be not expected to exceed 30-50 grams per day.

How does xylitol protect women against thrush (Candida)? Thrush is caused by an overgrowth of the yeast-like fungus, Candida albicans. Yeast thrives on sugar. Substituting xylitol for sugar helps lessen the incidence and severity of thrush by depriving yeast of its food source. Xylitol also helps reduce thrush through its fermentation in the gut by friendly bacteria, which proliferate and whose increased numbers then crowd out growth by pathogenic micro-organisms like C. albicans.

What research has been done on xylitol chewing gum? A large number of studies examining the positive role of xylitol in dental health have been done from the 1970’s until the present. Xylitol has recently received support from the Journal of the American Dental Association: "Xylitol is an effective preventive agent against dental caries. Consumption of xylitol-containing chewing gum has been demonstrated to reduce caries in Finnish teenagers by 30-60 percent. Studies conducted in Canada, Thailand, Polynesia and Belize have shown similar results..." A review of the literature conducted by Catherine Hayes at the Harvard School of Dental Medicine concluded that "xylitol can significantly decrease the incidence of dental caries” (16).

Why is xylitol an important aid in caries prevention? Xylitol is not fermented by oral bacteria like Streptacoccus mutans due to its unique 5-carbon backbone, and therefore cannot be converted to harmful acids. These bacteria are therefore stopped from producing plaque on the tooth surfaces, where the acid formed can attack the enamel leading to caries (9,14,15).

How does xylitol help tooth mineralisation? Studies have shown that decalcified sites on tooth enamel can remineralise after habitual xylitol use, and there is also an inhibitory effect on the demineralisation of sound enamel (11-13).

Does xylitol have a mineralising effect on bones as well as teeth? Several animal studies have shown increased bone strength, density and mineral content after dietary xylitol consumption (20,21,22).

How can mothers help protect their children’s teeth? Studies have demonstrated that mothers who chew xylitol gum while their children are infants reduce the levels of cariogenic bacteria in their children’s mouths. The children subsequently experience significantly less tooth decay (18), with the benefit extending years beyond the end of the study period (19).

Does xylitol in chewing gum protect teeth better than sorbitol which is so commonly used? Xylitol offers a much higher level of mouth protection than sorbitol (6,12,14). Sorbitol is another polyol but it has a 6 carbon structure and because of this, sorbitol can support the growth of cariogenic mutans streptococci and other oral bacteria after adaptation, which cause plaque and tooth decay. Xylitol is not fermented by mouth bacteria and has been shown in many clinical studies to reduce plaque and tooth decay.

How much xylitol gum should be chewed each day for maximal dental protection? Research shows that 6-7 grams of xylitol per day gives optimal protection. This means chewing 2 pieces of gum at least 4-5 times daily. The gum should be chewed immediately after a meal or a snack (5).

How does xylitol take care of a mouth dryness problem? In terms of dental health, it is good to increase the salivary flow rate as often as possible. This keeps the pH of the mouth more alkaline and resistant to tooth decay. Xylitol in chewing gum stimulates salivary flow and is therefore also useful for the protecting the teeth of people who suffer from dry mouth.

How does xylitol aid in preventing middle ear infections? During 1990, an estimated 24.5 million visits were made to office-based physicians in the United States at which the principal diagnosis was a middle ear infection, or otitis media. Xylitol acts by suppressing the growth of the nasopharyngeal bacteria responsible. Well-controlled studies in children demonstrate that using xylitol sweetened chewing gum reduces or prevents the recurrence of Acute Otitis Media or AOM (17).

Is xylitol safe? Yes it is. The oral and metabolic safety of xylitol has been exhaustively assessed by various international and national regulatory authorities. It was approved for use in the United Sates by the FDA in 1963, and in 1983 the Joint Expert Committee on Food Additives (JECFA). A collaboration between the World Health Organisation (WHO) and the Food and Agricultural Organisation (FAO) recommended that no daily limit be placed on xylitol consumption (the safest category for a food additive), It was further approved in 1994 by the UK Ministry of Agriculture, Fisheries and Foods (MAFF), and also the EU (although prior to this date xylitol was approved at national level in more than 40 countries). In 1997, approval was given by the Japanese Ministry of Health and Welfare.

If I am counting carbohydrates in my diet, how much do I calculate for xylitol? Xylitol has 75% of its content classed as “unavailable carbohydrate”. This is because most of the xylitol eaten passes through to the lower intestine and is not converted to glucose. Therefore only one quarter of the weight of xylitol can be counted as carbohydrate. (Note: nutrition information panels often subtract polyols like xylitol completely from the carbohydrate count.)

REFERENCES Makinen KK (2000) Can the pentitol-hexitol theory explain the clinical observations made with xylitol? Medical Hypotheses 54(4): 603-613 Makinen KK (1978) Biochemical principles of the use of xylitol in medicine and nutrition with special consideration of dental aspects. Birkhauser Verlag, Basel. Brunzell,JD (1978) Use of fructose, xylitol, or sorbitol as a sweetener in diabetes mellitus. Diabetes Care 1:223-230 Talbot, JM and Fisher KD (1978) The need for special foods and sugar substitutes by individuals with diabetes mellitus. Diabetes Care 1: 231-240 Makinen KK (1997) History, Safety and Dental Properties of Xylitol. In “Xylitol from A-Z”, ed. KK Makinen, A Suzuki and M. Fukudu, TP Japan press, Tokyo (in Japanese). Translated on website Xylitol.org Cronin M, Gordon J, Reardon R and Balbo F (1994) Three clinical trials comparing xylitol- and sorbitol-containing chewing gums for their effect on supragingival plaque accumulation. J Clin Dent 5: 106-109 Makinen KK, Bennett CA, Hujoel PP, Isokangas PJ, Isotupa KP and Pape PR (1995) Xylitol chewing gums and caries rates: a 40-month cohort study. J Dent Res 74: 1904-1913 Isokangas P (1987) Xylitol chewing gum in caries protection. A longitudinal study in Finnish schoolchildren. Proc Finn Dent Soc 83(suppl 1): 1-117 Makinen, KK (1992) Dietary prevention of dental caries by xylitol-clinical effectiveness and safety. J. App Nut 44: 16-28 Kandelman D and Gagnoni G (1987) Effect of xylitol chewing gum on dental caries. J Dent Res 66(8): 1407-1411. Arends J, Christoffersen J and Schuthoff J (1984) Influence of xylitol on demineralisation of enamel. Caries Res 18: 296-301 Steinberg LM, Odusola F and Mandel ID (1992) Remineralising potential, antiplaque and antigingivitis effects of xylitol and sorbitol sweetened gum. Clin Prev Dent 14: 31-34 Smits MT and Arends J (1988) Influence of xylitol- and fluoride-containing toothpaste on the remineralisation of surface softened enamel defects in vivo. Caries Res 19: 528-535 Soderling E, Alaraisanen L, Scheinen A and Makinen K K (1987) Effect of xylitol and sorbitol on polysaccharide production by and adhesive properties of Streptacoccus mutans. Caries Res 21: 109-116 Knuttila M L and Makinen K (1975) Effect of xylitol on the growth and metabolism of Streptacoccus mutans. Caries Res 59: 177-189 Hayes, C (2001) The effect of non-cariogenic sweeteners on the prevention of dental caries: A review of the evidence. J Dent Educ 65: 1106-1109 Uhari M, Kontiokari T, Koskela M and Niemela M (1996) Xylitol chewing gum in prevention of acute otitis media: double blind randomised trial. Br Med J 313: 1180-1184 Soderling E, Isokangas P, Pienihakkinen K and Tenovuo J (2000) Influence of maternal xylitol consumption on acquisition of mutans streptococci by infants. J Dent Res 79(3): 882-887 Isokangas P, Soderling E, Pienihakkinen K and Alanen P (2000) Occurrence of dental decay in children after maternal consumption of xylitol chewing gum, a follow up from 0 to 5 years of age J. Dent Res 79(11): 1885-1889 Mattila PT,Svanberg MJ, Jamsa T and Knuuttila ML (2002) Improved bone biomechanical properties in xylitol-fed aged rats. Metabolism 51(1): 92-6 Mattila PT, Svanberg MJ and Knuuttila ML (2001) Increased bone volume and bone mineral content in xylitol-fed aged rats. Gerontol 47(6): 300-5. Pauli, T, M Mattila, J Svanberg, P Pokka, et al. (1998) Dietary xylitol protects against weakening of bone biomechanical properties in ovariectomized rats. J.Nutr 128: 1811-1814.