Sugar-free gum, sweets and soft drinks, marketed as healthy alternatives to sugary products, can damage teeth, cause gastric problems and are unlikely to promote weight loss, research claims.
A study review in the British Dental Journal (BDJ) found that sugar-free foods and drinks contain acidic additives that may cause dental problems by eroding the enamel on consumers' teeth.
Disclosure of what the authors call a "hidden risk" could affect sales of sugar-free products, especially given what the paper describes as consumers' blind confidence in such products as a good thing.
The paper, Are sugar-free confections really beneficial for dental health?, examined the role of sugar substitutes used in products to reduce the risk of tooth decay. While one commonly used group of substitutes, called sugar alcohols, or polyols, do lessen the risk of cavities, they can cause acidity in the mouth that then leads to erosion of teeth enamel, says the paper.
These substitutes include xylitol, which the European commission has allowed to market itself as a "tooth friendly" ingredient in chewing gum. Xylitol is widely-used in sugar-free products sold in the UK, but not in soft drinks [see footnote].
The literature review, by academics from the universities of Boston, Helsinki and Southern Nevada, concludes: "As the use of sorbitol and xylitol containing products increases, the public should be educated on the hidden risk of dental erosion due to acidic additives, as well as the adverse effects of gastric disturbance and osmotic diarrhoea. Especially in sugar-free products, these adverse effects may be more insidious because the public has blind confidence that they are oral health friendly."
It adds: "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."
The review raises the wider question of what health-related claims made on behalf of products can be trusted, said Stephen Hancocks, the BDJ's editor-in-chief. "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 is it not saying? Sugar-free may seem to indicate that a sweet or other product is tooth friendly, but this is not automatically the case," he wrote in a commentary on the findings.
Given sugar-free products' role in erosion of dental enamel, and doubts over perceptions of them as helping users to consume fewer calories, he continued, "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."
Professor Damien Walmsley, scientific adviser to the British Dental Association, which represents dentists, said excess use of sugar-free products containing fruit flavourings could rot the enamel covering the dentine in teeth and ultimately cause teeth to dissolve.
• This footnote was added on 24 November 2011. The sweeteners xylitol and sorbitol, which the study looked at, are used in sugar-free gum, sweets and soft drinks in the US, but are not permitted in soft drinks in the European Union.
