Xylitol

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Eva Söderling - One of the best experts on this subject based on the ideXlab platform.

  • Controversies around Xylitol.
    European journal of dentistry, 2009
    Co-Authors: Eva Söderling
    Abstract:

    Xylitol research has been conducted since the early 70’s; at the beginning of 2009 there were almost 500 PubMed- indexed papers on “Xylitol and dental”. Xylitol research was initiated in Finland, but nowadays the majority of papers are published by non-Finnish authors. Xylitol studies have been criticized mainly by European researchers. This criticism is reflected for example in the most recent textbook of cariology, Dental Caries – The Disease and its Clinical Management (2008), used by students in all Nordic countries. It shows a figure with reduction in caries occurrence in the Turku Sugar Studies as an example, not of the effect of total substitution of dietary sugars with Xylitol, but rather “indicating the importance of removal of sugar from the diet, rather than starch, in caries control“. Moreover, a frequently cited review in Caries Research in 2004 came to the conclusion that “there is no evidence for a caries-therapeutic effect of Xylitol”.1 Xylitol studies are easy to criticize especially by authors who have never been involved in field trials. For example, to avoid exchange of test products between children of the same class randomisation has to be done by schools or school classes. This is rarely recognized by the critics of Xylitol studies. In addition, it is hard to find volunteers to comply with 2–3 years chewing of a hard and tasteless gum base, which is the control often suggested for chewing gum trials. Polyols like maltitol and sorbitol are by no means inert and are thus not valid controls for Xylitol. Fortunately, US dental experts have critically, but positively, conducted research and reviewed the literature on Xylitol.2–5 One consequence of practical problems associated with field trials is that in systematic reviews of methods for caries control and prevention the strict exclusion criteria leave only few Xylitol studies for evaluation. For example, the inclusion criteria for a Swedish systematic review on methods of caries prevention (SBU; www.sbu.se) were so strict that hardly any recommendations concerning caries prevention could be made. This also applied to Xylitol: according to the report, the evidence on the clinical efficacy for Xylitol was inconclusive. In a critical evaluation of the SBU report, the following question was asked “where does this leave the confused dental practitioner, who has to offer chairside advice to patients, but cannot wait of further (good-quality) research to be conducted and published, providing a more solid evidence-base?” (Stillman-Lowe, 2005). On the other hand, Xylitol has been recommended for use in caries control and prevention by several dental associations. Also the European Food Safety Authority evaluated the literature on Xylitol in 2008 and came to the conclusion that “Xylitol chewing gum reduces the risk of caries in children”. The claim had to be reformulated since chewing gum is not a medicine and can thus not be claimed to reduce the risk of a disease, caries. In Europe, there is a strong interest not to give Xylitol a better status than for other polyol sweeteners. Xylitol differs from other polyols as is obvious to all experts familiar with microbiology. Xylitol has beneficial effects on the oral flora not shared by other polyols. The evidence so far supports specific Xylitol-effects on oral bacteria, but not on saliva. Xylitol cannot be metabolized by plaque bacteria, contrary to sorbitol and other 6-carbon polyols, and may thus favour mineralization. The accumulated evidence suggests that 1) mutans streptococci are the target organisms of Xylitol in vivo, 2) mutans streptococci are reduced and stay on a lower level even during long-term Xylitol consumption as long as the consumption lasts, 3) Xylitol consumption reduces the accumulation of plaque, 4) Xylitol consumed by mothers reduces the mother-child transmission of mutans streptococci and consequently, caries occurrence in their children,6,7 and 5) Xylitol consumption reduces the risk of caries in children.4 In clinical trials on Xylitol mostly chewing gum with high Xylitol concentrations has been used. Studies with low daily doses of Xylitol are known as a rule to fail to show any caries-preventive effects. To obtain beneficial Xylitol-effects on mutans streptococci, on plaque and caries occurrence Xylitol must be consumed three times or more per day, with a daily dose of 5–6 grams.4,7 When using chewing gums or pastilles, saliva stimulation always occurs due to chewing or sucking. Some authors have claimed that the beneficial effects of Xylitol are solely based on saliva stimulation and that all sugar-free gums are similar in this respect. In fact, in conditions where caries occurrence is high, even sorbitol gum can prevent caries.8 A recent study elegantly shows caries prevention with Xylitol without any saliva stimulation. In this study fifteen-month-old children were given Xylitol or sorbitol syrup with a syringe for 12 months.9 The Xylitol syrup prevented early childhood caries effectively, while sorbitol had no effect. In spite of the abundant literature still more studies are needed on the action of Xylitol. Biofilm models could be very useful in Xylitol research. There is a clear need for properly designed, randomized, controlled, clinical trials to demonstrate 1) the feasibility of Xylitol prevention in different populations with different dietary and oral hygiene habits, 2) suitable vehicles to deliver Xylitol, 3) the extent to which Xylitol can be “diluted” with other polyols without losing the caries preventive effects, and 4) the minimum daily Xylitol dose and frequency of Xylitol are needed to obtain the expected Xylitol-effects on mutans streptococci, plaque and most importantly, on caries occurrence. Clinical trials often aim to improve treatment methods. When several clinical trials give similar results, clinicians can be given treatment guidelines based on findings verified by research. In this way research serves the clinicians in treating patients according to evidence-based solid information. Systematic reviews are currently required to update guidelines for caries prevention. As such, critical evaluation of the existing literature is a positive goal, but if it leads to a situation where no treatment guidelines can be given, something is wrong. This also applies to Xylitol studies. Though strict inclusion criteria prevent conclusions based on systematic reviews of the literature, evidence-based treatment guidelines can still be given for the use of Xylitol. Xylitol is a useful adjunct to traditional methods for caries control and prevention. Caries prevention with Xylitol has been claimed to be expensive, but if true primary prevention is obtained, as demonstrated in the mother-child study,6,7 it may be worth it.

  • Growth Inhibition of Streptococcus mutans with Low Xylitol Concentrations
    Current microbiology, 2008
    Co-Authors: Eva Söderling, Tiina C. Ekman, T Taipale
    Abstract:

    No studies on the concentration dependency of the inhibition of Streptococcus mutans with Xylitol are available. We studied Xylitol-induced growth inhibition of two type strains, S. mutans NCTC 10449 and Ingbritt, and three clinical isolates of S. mutans. The strains were grown in Brain Hearth Infusion Medium in the presence of 0.001% (0.066 mM), 0.005% (0.33 mM), 0.01% (0.66 mM), 0.1% (6.6 mM), and 1% (66 mM) Xylitol. Growth was followed by measuring the absorbance at a wavelength of 660 nm. The highest Xylitol concentration tested in this study, 1%, showed mean inhibition percentages ranging from 61% to 76% when the growth inhibition of the five strains was compared to the control without Xylitol at log-phase. For 0.1% Xylitol, the inhibition percentages ranged from 22% to 59%. A concentration dependency was seen in the growth inhibition, with 0.01% Xylitol being the lowest Xylitol concentration inhibiting all five strains significantly (p < 0.001). The growth inhibition percentages determined for 0.01% Xylitol, however, were low, and the inhibition was significantly weaker as compared to 0.1% and 1% Xylitol. Our results suggest that low Xylitol concentrations of 0.1% (6.6 mM) could inhibit mutans streptococci in vivo but even lower Xylitol concentrations may be inhibitory.

Yue-qin Tang - One of the best experts on this subject based on the ideXlab platform.

  • Improving Xylitol yield by deletion of endogenous Xylitol-assimilating genes: a study of industrial Saccharomyces cerevisiae in fermentation of glucose and xylose
    FEMS yeast research, 2020
    Co-Authors: Bai-xue Yang, Cai-yun Xie, Zi-yuan Xia, Min Gou, Yue-qin Tang
    Abstract:

    Engineered Saccharomyces cerevisiae can reduce xylose to Xylitol. However, in S. cerevisiae, there are several endogenous enzymes including Xylitol dehydrogenase encoded by XYL2, sorbitol dehydrogenases encoded by SOR1/SOR2, and xylulokinase encoded by XKS1 may lead to the assimilation of Xylitol. In this study, to increase Xylitol accumulation, these genes were separately deleted through CRISPR/Cas9 system. Their effects on Xylitol yield of an industrial S. cerevisiae CK17 overexpressing Candida tropicalis XYL1 (encoding xylose reductase) were investigated. Deletion of SOR1/SOR2 or XKS1 increased the Xylitol yield in both batch and fed-batch fermentation with different concentrations of glucose and xylose. The analysis of the transcription level of key genes in the mutants during fed-batch fermentation suggests that SOR1/SOR2 are more crucially responsible for Xylitol oxidation than XYL2 under the genetic background of S. cerevisiae CK17. The deletion of XKS1 gene could also weaken SOR1/SOR2 expression, thereby increasing the Xylitol accumulation. The XKS1-deleted strain CK17ΔXKS1 produced 46.17 g L-1 of Xylitol and reached a Xylitol yield of 0.92 g g-1 during simultaneous saccharification and fermentation (SSF) of pretreated corn stover slurry. Therefore, the deletion of XKS1 gene provides a promising strategy to meet the industrial demands for Xylitol production from lignocellulosic biomass.

Matti Leisola - One of the best experts on this subject based on the ideXlab platform.

  • A rare sugar Xylitol. Part II: biotechnological production and future applications of Xylitol
    Applied Microbiology and Biotechnology, 2007
    Co-Authors: Tom Birger Granström, Ken Izumori, Matti Leisola
    Abstract:

    Xylitol is the first rare sugar that has global markets. It has beneficial health properties and represents an alternative to current conventional sweeteners. Industrially, Xylitol is produced by chemical hydrogenation of d -xylose into Xylitol. The biotechnological method of producing Xylitol by metabolically engineered yeasts, Saccharomyces cerevisiae or Candida , has been studied as an alternative to the chemical method. Due to the industrial scale of production, Xylitol serves as an inexpensive starting material for the production of other rare sugars. The second part of this mini-review on Xylitol will look more closely at the biotechnological production and future applications of the rare sugar, Xylitol.

Arthur C Ouwehand - One of the best experts on this subject based on the ideXlab platform.

  • Xylitol s health benefits beyond dental health a comprehensive review
    Nutrients, 2019
    Co-Authors: Krista Salli, Markus J Lehtinen, Kirsti Tiihonen, Arthur C Ouwehand
    Abstract:

    Xylitol has been widely documented to have dental health benefits, such as reducing the risk for dental caries. Here we report on other health benefits that have been investigated for Xylitol. In skin, Xylitol has been reported to improve barrier function and suppress the growth of potential skin pathogens. As a non-digestible carbohydrate, Xylitol enters the colon where it is fermented by members of the colonic microbiota; species of the genus Anaerostipes have been reported to ferment Xylitol and produce butyrate. The most common Lactobacillus and Bifidobacterium species do not appear to be able to grow on Xylitol. The non-digestible but fermentable nature of Xylitol also contributes to a constipation relieving effect and improved bone mineral density. Xylitol also modulates the immune system, which, together with its antimicrobial activity contribute to a reduced respiratory tract infection, sinusitis, and otitis media risk. As a low caloric sweetener, Xylitol may contribute to weight management. It has been suggested that Xylitol also increases satiety, but these results are not convincing yet. The benefit of Xylitol on metabolic health, in addition to the benefit of the mere replacement of sucrose, remains to be determined in humans. Additional health benefits of Xylitol have thus been reported and indicate further opportunities but need to be confirmed in human studies.

  • Effects of Xylitol and Sucrose Mint Products on Streptococcus mutans Colonization in a Dental Simulator Model
    Current Microbiology, 2017
    Co-Authors: Krista M. Salli, Ulvi K. Gürsoy, Eva M. Söderling, Arthur C Ouwehand
    Abstract:

    Few laboratory methods exist for evaluating the cariogenicity of food ingredients. In this study, a dental simulator was used to determine the effects of commercial sucrose and Xylitol mint products on the adherence and planktonic growth of Streptococcus mutans . Solutions (3% w/v) of sucrose, Xylitol, sucrose mints, Xylitol mints, Xylitol with 0.02% peppermint oil (PO), and 0.02% PO alone were used to test the levels of planktonic and adhered S. mutans . A dental simulator with continuous artificial saliva flow, constant temperature, and mixing was used as a test environment and hydroxyapatite (HA) discs were implemented into the model to simulate the tooth surface. Bacterial content was quantified by qPCR. Compared with the artificial saliva alone, sucrose and sucrose mints increased the numbers of HA-attached S. mutans , whereas Xylitol decreased them. Similarly, planktonic S. mutans quantities rose with sucrose and declined with Xylitol and Xylitol mints. Versus sucrose mints, Xylitol mints significantly reduced the counts of HA-bound and planktonic S. mutans . Similar results were observed with the main ingredients of both types of mints separately. PO-supplemented artificial saliva did not influence the numbers of S. mutans that attached to HA or planktonic S. mutans compared with artificial saliva control. In our dental simulator model, Xylitol reduced the counts of adhering and planktonic S.mutans . The mints behaved similarly as their pure, main ingredients—sucrose or Xylitol, respectively. PO, which has been suggested to have antimicrobial properties, did not influence S. mutans colonization.

Matti Uhari - One of the best experts on this subject based on the ideXlab platform.

  • effect of Xylitol and other carbon sources on streptococcus pneumoniae biofilm formation and gene expression in vitro
    Apmis, 2011
    Co-Authors: Paula Kurola, Matti Uhari, Terhi Tapiainen, Jenny Sevander, Tarja Kaijalainen, Maija Leinonen, Annika Saukkoriipi
    Abstract:

    Xylitol inhibits the growth of Streptococcus pneumoniae. In clinical trials, Xylitol decreased the occurrence of acute otitis media in day-care children, but did not decrease nasopharyngeal carriage of pneumococci. We hypothesized that Xylitol inhibits biofilm formation of pneumococci, and measured biofilm formation and gene expression levels of the capsule gene cpsB and two other genes: autolysin encoding gene lytA and competence gene comA in different growth media in vitro. Twenty pneumococcal isolates were grown on polystyrene plates for 18 h in test media containing 0.5% Xylitol, 0.5% glucose, 0.5% Xylitol and 0.5% glucose, 0.5% fructose, 0.5% Xylitol and 0.5% fructose or brain heart infusion (BHI) medium supplemented with 10% horse serum. Gene expression levels were measured after 5 h of growth using a relative quantification method with calibrator normalization. Exposure to Xylitol lowered OD values, which were used as an indication of biofilm, compared with BHI medium, but when the medium was supplemented with glucose or fructose, biofilm formation was enhanced and the inhibitory effect of Xylitol on biofilm formation was not observed. Xylitol also lowered lytA expression levels. Changes in biofilm formation in response to different sugar compounds may partly explain the efficacy of Xylitol to prevent acute otitis media in previous clinical trials.

  • Xylitol in preventing acute otitis media.
    Vaccine, 2000
    Co-Authors: Matti Uhari, Terhi Tapiainen, Tero Kontiokari
    Abstract:

    Xylitol is a polyol sugar alcohol and is referred to as birch sugar, because it can be produced from birch. Natural sources of Xylitol include plums, strawberries, raspberries and rowan berries. Xylitol inhibits the growth of Streptococcus pneumoniae and it inhibits the attachment of both pneumococci and Haemophilus influenzae on the nasopharyngeal cells. In two clinical trials Xylitol was found efficient to prevent the development of acute otitis media with a daily dose of 8.4-10 g of Xylitol given in five divided doses. The efficacy in these 2-3 months follow-up trials was approximately 40% when chewing gum was used and approximately 30% with Xylitol syrup. The need to use antimicrobials reduced markedly when using Xylitol. In a high-risk group of children with tympanostomy tubes Xylitol was ineffective in preventing otitis. Xylitol appears to be an attractive alternative to prevent acute otitis media. A more practical frequency of doses should be found before its use can be widely recommended.

  • a novel use of Xylitol sugar in preventing acute otitis media
    Pediatrics, 1998
    Co-Authors: Matti Uhari, Tero Kontiokari, Marjo Niemela
    Abstract:

    Background. Xylitol, a commonly used sweetener, is effective in preventing dental caries. As it inhibits the growth of pneumococci, we evaluated whether Xylitol could be effective in preventing acute otitis media (AOM). Design. Altogether, 857 healthy children recruited from day care centers were randomized to one of five treatment groups to receive control syrup (n = 165), Xylitol syrup (n = 159), control chewing gum (n = 178), Xylitol gum (n = 179), or Xylitol lozenge (n = 176). The daily dose of Xylitol varied from 8.4 g (chewing gum) to 10 g (syrup). The design was a 3-month randomized, controlled trial, blinded within the chewing gum and syrup groups. The occurrence of AOM each time the child showed any symptoms of respiratory infection was the main outcome. Results. Although at least one event of AOM was experienced by 68 (41%) of the 165 children who received control syrup, only 46 (29%) of the 159 children receiving Xylitol syrup were affected, for a 30% decrease (95% confidence interval [CI]: 4.6%–55.4%). Likewise, the occurrence of otitis decreased by 40% compared with control subjects in the children who received Xylitol chewing gum (CI: 10.0%–71.1%) and by 20% in the lozenge group (CI: −12.9%–51.4%). Thus, the occurrence of AOM during the follow-up period was significantly lower in those who received Xylitol syrup or gum, and these children required antimicrobials less often than did controls. Xylitol was well tolerated. Conclusions. Xylitol sugar, when given in a syrup or chewing gum, was effective in preventing AOM and decreasing the need for antimicrobials.