Background Various sugar substitutes have been introduced and are widely used in confections and beverages to avoid tooth decay from sugar and other fermentable carbohydrates. One group of sugar substitutes are sugar alcohols or polyols. They have been specifically used in foods for diabetic patients because polyols are not readily absorbed in the intestine and blood stream, preventing post-prandial elevation of glucose level. Additionally they may lower caloric intake.
Methods We searched PubMed, Cochrane Controlled Trials Registry, Cochrane Oral Health Review, Centre for Reviews and Dissemination in the UK, National Library for Public Health and a Centre for Evidence Based Dentistry website up to the end of October 2010, using the search terms 'sugar alcohol' or 'sugar-free' or 'polyols' and combined with a search with terms 'dental caries' or 'dental erosion'.
Results Xylitol, a polyol, has been approved by the US Food and Drug Administration for its non-cariogenic properties that actually reduce the risk of dental decay and recently, the European Union also officially approved a health claim about xylitol as a 'tooth friendly' component in chewing gums. Although the presence of acidic flavourings and preservatives in sugar-free products has received less attention, these additives may have adverse dental health effects, such as dental erosion. Furthermore, the term sugar-free may generate false security because people may automatically believe that sugar-free products are safe on teeth.
Conclusion We concluded that polyol-based sugar-free products may decrease dental caries incidence but they may bring another dental health risk, dental erosion, if they contain acidic flavouring. There is a need for properly conducted clinical studies in this area.
Sugar-free does not mean calorie-free. Some sugar-free products generate nearly 50% of calories produced by table sugar.
In general, sugar-free products may help prevent dental caries. However, if they contain acidic additives, it may increase the probability of demineralising enamel, thus causing dental erosion.
Avoiding acid-containing, usually fruit-flavoured sugar-free products may be beneficial.
H. Nadimi, H. Wesamaa, S. -J. Janket, P. Bollu, and J. H. Meurman British Dental Journal 2011; 211: E15
There is a children's play somewhere buried deep in my memory in which the recurring line is 'the Emperor always means what he says, but doesn't always say what he means'. The same might be applied to 'claims' made for products, especially health-related claims. That is, the claim might well mean what it says and be suitably backed-up by research evidence but does it fully say what it means, or alternatively, what it is not saying?
Sugar-free may seem to indicate that a sweet, or other product, is tooth friendly but this is not automatically the case. As disclosed in this paper, the level of acidity is also crucial in determining whether the confection may induce enamel loss leading to erosion, for example. Similarly, sugar-free might be perceived as meaning reduced calories thereby lulling people on restricted calorie diets into a sense of false security. The result is a minefield of confusion for the patient who is trying his or her very best to comply with healthy choices and a complex labyrinth of communication for the professional in attempting to convey practical advice.
As with a recent research paper on the constituents of chewing gum, it seems that fruit flavouring has a lot to answer for, bringing with it a potential for increased acidity and consequent harmful lowering of pH in the oral cavity. In terms of oral health education messages the answer would seem to be to provide the patient with as much background as possible to allow them to make informed choices while attempting not to confuse or overburden them with apparently conflicting advice. This is not an easy task and to some extent the likelihood is more that practitioners will begin to notice, perhaps erosion, in a patient and then use their own knowledge of the process to forensically track down the cause by careful questioning of that patient and their habits. While somewhat a case of shutting the stable door after the horse has bolted, it does provide a semi-preventive solution to an as yet unsolved problem, the analysis of claims; and that is what I mean to say.
The full paper can be accessed from the BDJ website (www.bdj.co.uk), under 'Research' in the table of contents for Volume 211 issue 7.